Thieaudio Legacy 4 Universal IEM


Reviewer at Sound Perfection Reviews
Formerly affiliated with HiFi Headphones
Crisp and clean
Pros: Clean and detail sound
Great value
Cons: Slightly thin at times
Could be borderline bright to some
Firstly I would like to thank Linsoul for sending me this sample to review.

*disclaimer: This sample was provided for the purpose of writing a review, no incentive was given to write a favourable review. All opinions expressed are my own subjective findings

Gear Used:
iBasso DX200 > Legacy 4
Topping D90 / A90 > Legacy 4


Tech Specs:
Frequency range: 20Hz-20KHz
Monitor Plug: 3.5mm
Connecto: 0.78mm 2PIN
Sensitivity: 108±0.5db
Impedance: 9.4Ω
Noise isolation: 26dB
Detachable cable: 120cm

Packaging, Build Quality and Accessories:

The Legacy 4 come in quite an impressive box, it is quite big with the brand name and model number in large font on the front. Once you open the large cardboard outer box you will find a case inside, this is where you will find the IEM’s nearly tucked into place with the accessories also neatly placed around them. It’s a really good unboxing experience, as you are greeted with a high quality box along with a great looking larger case that holds everything neatly inside.

The Legacy 4 look incredibly well built to me, the handmade housings are perfectly finished and the DIP switches and 2-pin sockets feel solid too. The included cable is really good, it’s silver plated copper and nice and pliable, which means it’s super comfortable in use too. The strain relief is great all round and I can’t fault these at all. I have got to point out how good these look in person too, the faceplate is gorgeous and has a slight sparkle to it, they really stand out and look more expensive than they really are.

Accessory wise you get the standard S/M/L silicone tips but in two different varieties, a small tool for changing the DIP switch settings and also a small carry case which fits the IEM’s in it perfectly. I quite like how Thieaudio included a smaller case within the bigger presentation case, a nice touch in my opinion. A few more tips and maybe a balanced cable would have been nice, but overall a good set of accessories.


Comfort and Isolation:

The fit of the Legacy 4 is excellent, I sometimes have trouble with certain universal IEM’s but these fit perfectly once I had found the right tips. The housing has smooth edges and the nozzle is at the correct angle to fit most peoples ears. The soft and pliable cable, along with well fitting pre-moulded ear-hooks definitely helps here and I found no problem with them over long listening sessions.

Isolation is really good, they work well for all sorts of use including noisy commuting and travelling.



The Legacy 4 come with 2 switches on each earphone, these change the sound signature slightly to fine tune the sound to your taste. Please note these switches don’t bring about drastic changes to the sound signature.

With both switches down you get the original tuning of the L4, with the left switch turned up you get ever so slightly enhanced bass but this is a very minor adjustment. Turning the right switch up will bring the midrange forward a little, they also benefit from a little added body but at the same time the upper midrange becomes even more forward than stock which won’t be to everyone’s taste.

This review is based on both switches down – the stock configuration.

Lows: The low end on the Legacy 4 can dig really deep when called for, and they have no problem with sub-bass notes when they are needed in the mix, however they are very controlled and tight sounding overall and never miss a beat. Those looking for a more bass oriented signature should definitely look elsewhere, the Legacy 4 have quite a well balanced tuning that has a focus on transparency and resolution rather than boosting any particular part of the frequency response. They are not lacking down low, and kicks are backed up with good body, there is articulation and acoustic has good body to it overall, they are just not overly emphasised down low.

Midrange: The midrange is a real standout point on the Legacy 4, you get a very clean and open presentation. In my personal opinion the midrange is a little too clinical at times, and could use a little more body overall, however if you favour clarity over a more organic tone these should fit the bill. There is a little emphasis in the upper midrange / lower treble that some may be a little sensitive to, but with well recorded material I never found them to be overly harsh. This is where that resolution comes in to play, they really do have the ability to show up flaws in recordings better than quite a few IEM’s in this price range. So apart from the slightly lean presentation the midrange manages to extract an impressive amount of detail, and is far from being recessed or dull and laid back.

Highs: As mentioned in the midrange section, there is a bit of a peak in the upper midrange / lower treble region, that brings out a bit of extra energy but could be problematic to some. Luckily I find this peak to be tolerable and from there upwards the treble is clean and crisp with excellent air and extension but without being too forward in the mix. Tonally the treble is actually very good, with accurate representation for the most part, cymbals sound realistic without ever sounding splashy, snares are snappy and overall the treble is faithful to the recording.

Soundstaging is good, a well focussed centre image with instruments surrounding it creates a good sized stage but without sounding detached. There is excellent separation and layering, and they handle fast and complex mixes without sounding congested. They are very tight and controlled, yet full when called for, this is a great trait to have.



I personally really enjoy the Legacy 4, they have the kind of tuning that I appreciate and enjoy a lot. It is a well balanced sound overall that has good impact and energy without sounding too coloured overall. They are a little on the brighter side due to the upper midrange / lower treble peak, but it is well within my tolerable limits and most shouldn’t find them problematic. The midrange is really insightful and definitely a focus point on these, yet they are also a brilliant all rounder if you are looking for something that is detailed and technical instead of warm and smooth. They are very good value for money, the build and sound are excellent for the price.

Sound Perfection Rating: 9.5/10 (stunning in both looks and sound)
I think the L4 is a very underrated IEM and is a good alternative to the ER2XR/SR given the meme fit.
@WAON303 Why? There is no similarities between the L4 and the ER2XR/SE, I believe. Or you are talking about the sound isolation?


Headphoneus Supremus
Thieaudio Legacy 4: Swirly looks, good sound; what more do you want?
Pros: Gorgeous looks.
Good fit.
Accessories, accessories, accessories
Sound, which while tunable still provides for a pleasant listen
Tuning switches worked for me
Good detail and air of note
Cons: Not quite enough bass
May sound "thin" to some
Some say switches are for show only
Extremely tough price point
Some may not like those gorgeous looks
Thieaudio Legacy 4 ($195): Swirly looks, good sound; what more do you want?

When Lillian contacted me about reviewing the Legacy 4, I accepted her invitation without hesitation. Having read a wee bit about the line, I knew the sound was getting good reviews. Not the hyped flavor-of-the-month type but real respect for everything from the builds to the sound. This is my first Thieaudio model and based upon my initial reactions and the deeper delve of long listening, I hope it is not my last. This is an excellent start.

I thank Lillian and Linsoul for the review sample. An open, honest review will be forthcoming. The unit is understood to be mine, unless asked back for; and may not be sold for a profit as that still remains a really uncool thing to do.

Legacy 4



Thieaudio was launched in 2019 as a creative endeavor of Linsoul Audio. The goal of Thieaudio was to serve as a creative platform for gathering the best teams of engineers to inspire revolutionary audio products for audiophiles and professionals alike. For each project, we hand select the most innovative and renowned engineers in his or her field to oversee the design, engineering, and manufacturing of the products. Gathering the momentum from the success of the Thieaudio Phantom planar magnetic headphones, as well as the Voyager, Legacy, and Signature series In-Ear Monitors (IEM’s), we are committed to the continual expansion on the limits of high-fidelity audio. We welcome you to join us and experience excellence in musical performance.

Legacy 4 innards:

The proprietary 8mm poly-membrane dynamic driver
Knowles TM and THIEAUDIO Customized Balanced Armatures
3-Way Crossover Network is integrated into a 2-switch tuning system
Paired with an OCC 4-core custom cable
Optional Upgrade EST cable is 2.5mm balanced cable comes with 3.5mm and 4.4mm adapter
Hand-crafted, tested for Quality Assurance


More intro information:

Legacy 4:
The Legacy 4 was designed concurrently with the Legacy 5 to provide a unique twist to the lineup. With the beloved budget model, the Legacy 3, and the natural and smooth sound signature of the Legacy 5 in mind, we wanted the Legacy 4 to be a middle ground - both in terms of the tuning and price. Utilizing a completely new in-house 8mm poly-membrane dynamic driver for the low end, the Legacy 4 provides the impactful slam of the Legacy 3 and 5, but with a faster speed and enhanced texture. This new driver matched with the tried and tested American Knowles ED29689 balanced armature (BA) and intuitive low-mid passive crossover design emphasizes a natural mid-frequency presentation. With a less aggressive crossover design than the Legacy 5, the mids of the Legacy 4 presents a more musical experience that ever so slightly adds a dash of warmth to the overall signature. With the partnership of Bellsing, we have developed a custom dual BA tweeter for the Legacy 4 that perfectly fits the mid BA driver. From the relaxed and smooth treble delivery of the Legacy 5, we have tuned the Legacy 4 to bring more upper treble presence, highlighting upper frequency overtones and details. This tuning and the extremely capable treble extension of our new tweeters brings an even greater level of airiness and shimmer to the mix, making the Legacy 4 an excellent IEM for both professional musicians and music enthusiasts alike. You can trust that the Legacy 4 will provide one of the most natural, accurate, and enjoyable musical experiences among any IEM’s of its class.


Model: Legacy 4
Frequency range: 20Hz-20KHz
Monitor Plug: 3.5mm
Connector: 0.78mm 2PIN
Sensitivity: 108±0.5db
Impedance: 9.4Ω
Noise isolation: 26dB
Detachable cable: 120cm

Gear used/compared:

Unique Melody 3DT ($399)
Oriolis Finschi ($179)
BQEYZ Spring 2 ($165)
DDHiFi Janus ($199)
Shozy Form 1.1 ($75)

Shanling M6 Pro
Cayin N6 mk2ii
HiBy R3 Pro Sabre


Dave Matthews
Joey Alexander-Warna album and others
Mark Knopfler-Laughs And Jokes And Drinks And Smokes
Santana w/ Mana- Corazon Espinado
twenty one pilots
Tedeschi Trucks Band
Big Head Todd & The Monsters-Beautiful World
Mark Knopfler-Down The Road Wherever
Elton John-yep, still good, still cool
Tidal MQA



Coming in a fairly small black rectangular box, the front is laden with the “THIEAUDIO LEGACY 4” words, and a graph on the back. Understated, especially after the box is opened. Once unlidded, you are met with a gray tweedish colored case that is almost as big as the box itself. Unzipping the semi-hard case, which has a protected zipper cover, you are met with another smaller case in which the included cable lies. Nestled in shaped semi-hard foam to the left are the gorgeous IEM’s. Below that you have a SOLID 4x credit card thick piece, replete with pegs for the included tips. It is actually held in place with Velcro tightly wrapped around it. I had a really hard time returning the Velcro around the board, so I tucked it under the aluminum. That aluminum also fits in very tightly to its requisite space.

A nice feature of the case is that the foam piece, which holds the IEM’s can be removed and a small to medium-small DAP can fit in there nicely. You could even place a larger DAP in place of the smaller case and have the Legacy 4 & cable to the left. I will admit I was not expecting two cases, let alone one so large. Frankly, the smaller case is what I will use mostly, but the larger case will hold other things such as extra tips, or cables. A nice addition to the kit, regardless.


Tuning Switch:

From the website: The Legacy 4 crossover network is integrated into a 2-switch tuning system that allows the user to define the level of bass and mids. This tuning system means you can find the perfect sound signature no matter your musical preference!

With both switches down, you get the “natural” sound of the IEM. Switching the left one up on both IEM’s, is for an added benefit of bass tuning. Reaching a bit deeper, with a good thump as well, this would be the preference for bass loving people. Switch the right one up only, and you enhance the mids, while the bass response becomes a bit withdrawn. Pushed forward, the vocals sound quite good but to me a bit too far forward. With both in the “on” position, you get enhanced bass and mids much like adding a quick fix of EQ, but to me the mid switch overrode the bass addition. For my testing, I left the left switch up as my preference.

The switches themselves are quite small, and I carefully used a bent paperclip to change. A system much like Dunu has on the SA-6, which can utilize your hand on the fly is a better choice in my mind. Regardless, the switch allows you to somewhat tailor the response of the 8mm dynamic driver and custom Knowles ED29689 balanced armature as well as the two Thieaudio balanced armatures. Stated as having a less aggressive crossover than the Legacy 3 or 5, the 4 sounds quite smooth across the spectrum, regardless of switch position.



One cannot help but be drawn to the IEM first, as it is highlighted in the upper left. Made from medical grade German resin, each pair is unique, since they are hand poured. As stated in another review, the look is stunning as well as unique and becoming more in vogue. I do appreciate this look since most of them are understated in their elegance and not garish in the least. Each earpiece is also matched to provide the closest pairing, tuning-wise possible.

The shell itself looks like a semi-custom shaped shell of semi-transparent greenish gray color. The insides are highlighted nicely as a result. I will admit that upon first look, I immediately thought I may have problems with fit, due to the protruding knob behind the nozzle. I did not. With a vent hole in top, including laden with a bronze colored insert, tuning of the lower end is helped by said vent.

Over the years I have come to appreciate looking inside the shell, when done properly. And the Legacy 4 is done properly. You can see the drivers, and the configuration. With sound tubes coming off of each, the balanced armatures are “herded into on tube, and the dynamic driver into another. As a result, there are two opening on top of the semi-short nozzle. The nozzle does have a slight “lip,” which helps holds tips in place. I tried both silicon and foam tips but stayed with the stock silicon tips throughout the testing.

The faceplate is a swirled cacophony of color, and as stated my pair is of an understated elegance, which appeals to me. A mix of copper, white, gray, blue, and sand-like sparkles surround the cat eye-like look of the middle. With a 3-D presence, the faceplate looks stunning. Under direct light you can imagine the 3-D layers of color as waves on an ocean, as the silver “THIEAUDIO” lettering takes on a subtlety not had when direct light is not on the unit. Under normal circumstances, the lettering is prominent but still understated. Shine a light on the shell, and the character changes. Nicely done.

The only “flaw” I could find is that the 2-pin cable does not lie flush against the shell when inserted. Both are pushed in all the way, but not flush. I also noted that one was considerably harder to push in, but I managed carefully.

The cable is 4-core OCC custom of 120cm length. There is a bit of tackiness to it, but the cable lies well, without tangle nor microphonics. Not wound overly tight, I never had a problem with tangling or snagging. The 3.5mm se jack is silver and straight, of good thickness as well. There is no over-ear guide, but a bend allows the cable to sit without bother even with my glasses on.

Once inserted, I had no problem (not that I had a problem inserting the IEM...) with fit or placement, as the Legacy 4 did not bind or fit at an odd angle. Sitting nearly flush as well, the Legacy 4 is an unobtrusive IEM, too. Using the silicon tips, seal is quite good with only a minor bleed into the ear cavity from outside noises. Once the music starts, all is good and right in the world.

The quality of offerings at this price continue a trend of excellent build quality that until recently was afforded only in the much higher price brackets. I am over the top excited this trend continues to trickle down the price level.



From the beginning, I was impressed with this affordable mid-fi entrant. Providing a fairly rich, and deep bass set the tone for near-silky smooth mids, with vocals that played very well with the warmth provided. Guitar work cut right through any perceived veiled character (there wasn’t any), just to let you know that this plays well. Plus, with a top end that does not offend me, even with both switches set to the “on” position; there was much to appreciate from the Legacy 4. If I had to glamour a prominence, it would be that the mids take the heart of the show, moving a bit forward and a bit up, but not in an offensive manner. Think of the drum major who goes about their business in a well, business-like manner and that would be a good assessment of the mids. This IEM seems to be working its way up the food chain of $200 IEMs as a result.

Again, that bass is present in enough amount (left switch in “on” position) to warrant respect, but not enough to push you into the rumble territory. Using the very good stock cable first (then a 2.5bal Effect Audio Ares II cable), I appreciated how succinct and tight the bass was, with decay on the faster side. There is good speed here as a result, which lends and air of authority and command that a slower decay might turn into a near-muddy mess.

The mids are to me the highlight, though. Clean and with a certain crispness, which accompanies the taut bass, guitar work is as succinct as the lowers, with a precision that works without being too airy or dry. I would not describe the sound as “wet,” as I’m not even sure what that would be other than rich, warm and vibrant; but use those three adjectives before the semi-colon and that would be an apt descriptor of how I hear the mids. The sound is developing into what I would say is akin to what the Finschi does for Oriolus: provide an excellent intro into the world of Thieaudio.

Since I left the left switch on, and the right “off,” I will use that as the baseline for the treble sound. A good feeling of air between the notes is had up top, without becoming disjoined from the other aspects of the sound signature. Clarity of that air is ever present on such songs as Ottmar Liebert’s Snakecharmer. A certain staccato of sound emanates from the uppers, which is both clean and refreshing without being thin or hollow. A certain delicacy of sound comes forth as a result of the treble tuning. If I had one wish regarding the three sections mention here, after a bit more bass thump it would be a slightly higher push of the treble note. Which if you follow my other reviews is a turn the opposite direction since I do not like too much push up top. Let’s simply ask for a bit more sparkle up top and this would be the excellent complement I wish for. Turning the right hand switch up only pushes the mids a bit more forward and up, like a 6dB push might from a good EQ. Therefore, I can happily live with tuning as such laid out.



Taken separately since I have addressed somewhat the airy separation of note above; the soundstage is neither large and expansive, nor narrow and small. I would say that this is about a cubic as any I have had of late, with the center point pushed slightly forward and up. Call it middle of the road if you wish, but I prefer to call it not wanting to intrude upon the other aspects. A common theme is developing: one of which the harmonic balance of all qualities with regard to the sound signature playing well together is coming forth. That is not to call this boring or middle of the road, but balanced and having no need to temper or intrude upon the experience as such.


As I mentioned above, speed and decay are quite good, which may seem a bit antithesis to the balanced signature noted as well. I do not think that would be the case, as the timbre gives that speed quality a decisive yet forgiving tonality that works to provide a reality to the sound, which is the intended result. It is one thing to be decisive and dry/analytical. It is another to be decisive and open/honest. That would be how I hear the Legacy 4. Balanced, decisive and good timbre representing that honesty of presentation.


Thieaudio Legacy 4 ($195) v Unique Melody 3DT ($399):

I start with the most expensive of those listed here for a reason. I made reference to the Legacy 4 in the 3DT thread as the pairs both arrived a day apart. This can be good and bad. Good for comparative purpose. Bad for deadline purposes. The other part of that is I also mentioned in the thread that I may like the “secret IEM” more. The secret one is the Legacy 4. And after thorough listening of both (the good part), I can hopefully pinpoint the differences and similarities.

First and foremost, I like both quite a lot. The fit of the Legacy 4 is easier on my ears as it is a bit smaller. To attain a good seal and sound quality I like from the UM, I had to use a spare pair of my Comply’s. Not bad mind you, but the comfort level is not on par as a result. I will quality that using the included silicon’s I had no trouble for long periods, and the sound was just fine. I wanted a bit more bass push, hence the Comply’s.

Next, and to me the biggest difference is that the UM provides a more mature sound. Richer of note, but also presenting a cleanliness that matches and slightly betters the Legacy 4 separate the two. Warmer tonalities (partly the Comply’s) help separate that maturity, but I am thoroughly impressed by the succinctness of note, which permeates the overall character of the 3DT. Considering this is the “entry level” UM, this is quite the fine bird. I have always appreciated the UM tuning as well. Bass when needed, and a quality of note that just hits me like a fine bowl of oatmeal, with pecans, Craisins and brown sugar on a cold winter’s morn. Steaming hot with my organic local cup of Joe makes for a wonderful setting. That is how I feel about the UM 3DT. It hits the right spot.

Calling it the big brother of the Legacy 4 would not be an insult, but something for the Legacy 4 to look up to, instead.


Thieaudio Legacy 4 ($195) v Oriolis Finschi ($179):

Mentioned often in my reviews, the Finschi is my baseline at this price, although some have come close (see those right below...). From my first listen, this set the tone. That was a bit over two years ago, and you can clearly see how time and tuning has proceeded. The Finschi bass is sublime in its presentation, tying to those slightly uplifted mids quite well. There is a bit of cover presented from the mids, which tames what could have been near-perfect mids, in instrumentation and vocal support, but hearing the newer models, you find that they may well have surpassed the Finschi. But here is where the others may still fall behind, including the Legacy 4: a richness of tone that is such sweet and succulent in representing the emotion of song. For that there is still no peer in this price to me.

For a wonderfully balanced signature, the Legacy 4 has surpassed the Finschi, but if you desire a warm, richness of tone for your pleasure, then there are still few, which can match or surpass the Finschi in this price to me.

Thieaudio Legacy 4 ($195) v BQEYZ Spring 2 ($165):

Like the name (yes, bad punnery coming...) the Spring 2 is a breath. A breath of clean, clear and crisp air. The Spring 2 has a much more open sound than the Legacy 4 and a certain lilt of which I like very much. This is a wide-open fun sounding IEM, without being frivolous or too carefree. What might be lost in detail retrieval is more than made up for in its airy presentation. Yes, usually with clarity and detail comes a certain airy presentation, but here the Spring 2 is slightly behind the Legacy 4 with regard to detail retrieval. But then again oh my, that fun sound!

The spring 2 is the IEM, which you would bring on your commute to lift you up in the morning, or that Friday afternoon commute IEM, knowing you have the weekend at hand. The Legacy 4 is the one to get you through the work week, knowing you can count on its speed and detail for accuracy. I like both, and they complement each other quite nicely.

Thieaudio Legacy 4 ($195) v DDHiFi Janus ($199):

I admit no fault in liking the DDHiFi lineup. None at all. I have yet to find something in their line of wares, which is not only functional but also fills a niche of need nicely. The C2020 case is my daily carrier of DAP’s x2 and enough of what I am testing to keep me happy.

Innovative and at the leading edge of much in which I love, DD did it again with the Janus. I opted to wait for a production model, as I felt my ears were not worthy of tuning such as others are and were at the time. I am glad I waited. The finished product is as fun as the Spring 2, but with an added benefit of a slight touch of warmth and richness of which I value in my listening pleasures. I am still torn between using the Janus up or down, and thankfully have both the Air and Forest, so both are in use often.

As for comparing to the Legacy 4, there is a bit less bass push, but the speed of decay in the single dynamic driver is impressive, nonetheless. Vocals and mids are pushed forward as well but are not as clean as the Legacy 4 (using Comply tips on both). But moving upward, there is a that bit of sparkle in the Janus, that I desired in the Legacy 4. So, this really is a wash. If pure sound is your goal, both are good choices. If you want a bit better air and fit, then the Legacy 4 would be the choice here. A bit more sparkle and a fun-factor? Then the Janus is the choice of these two.


Thieaudio Legacy 4 ($195) v Shozy Form 1.1 ($75):

I included the Shozy because it is my favorite Shozy to date. Even more so than the AAW-Shozy combination. For the price, the Form 1.1 is really quite hard to beat, and as another contributor @B9Scrambler notes; moving up to the Form 1.4, while good may not be needed because the 1.1 is so good. I would agree, hence the inclusion.

With a slightly “pinched” mid, that pushes the vocals and works such as guitar music more forward, the 1.1 is not what I would call shouty or in your face. Rather I would call it the fruition of fun-forward delight. It does not have the push down low of the Legacy 4 either. But no matter, the sound provides a rich, vibrant tonality that accompanies that mid push nicely. Add in some sparkle up top and you get a thoroughly satisfying sound emanating from a sub-$100 IEM. It is still amazing to me how Chinese fidelity has matured in such a short time over the last five years. To me the Shozy form 1.1 rode in on the forefront of that push towards higher quality and a more mature sound, that is balanced (not necessarily all, but many manufacturers thankfully lost that SHOUTY BIT, which annoyed many), providing a tempered treble note, and quality build to match. Good to see, and the 1.1 has the goods to back that up.

If it came down to the two though, the Legacy 4 fits my tonality more, with better speed and a deeper reach down low. Add in that the mids are so sumptuous and it really defines (or redefines to me) the category. The 1.1 is not shoddy in any form, but you see the maturing levels of the Legacy 4 show in the fruition of sound springing forth. Gah, what a fruity, flowering mash of a sentence. Apologies.



The Legacy 4 scaled well across many sources, letting the source be the definitive difference. Using the HiBy R5 Saber, the sound was a bit mellow, and somewhat thin. That is until I realized that the detail was the definitive aspect of what I heard. Concise without any slowness to it, Ottmar Liebert on Snakecharmer was succinct, detailed and crisp. That “thinness” of which I spoke actually came out as clarity. I did have to turn the volume knob up to fully appreciate the pairing, but still enjoyed the sound at near-minimal levels. This is a very good mid-fi pairing.

Switching to the Shanling M6 Pro, I immediately noticed the added verve of the dual DAC set up. Much more energy emanated from the duo, and there was a very nice rich tonality to the pair. Coming across as strong and vibrant, but without being bright or overly sparkly; the pair was probably my favorite. The Shanling is able to quickly alter its personality using the gain feature and single/dual-DAC features. A stunning performer, which added and complimented the Legacy 4 allowing the strengths to come out of both.

Having the iFi Zen CAN in for review as well has its benefits. I have used it for the HiFiMan HE-R10P as well as the UM 3DT along with the Legacy 4. Showing it can compete pretty darn well across the listening devices, it did pair well with the Legacy 4. I did find that when using both the XBass & 3D features, the sound became a bit loose. Bass overrode the overall quality and muddied the mids a bit too much on some songs. I still enjoyed it mind you but compared to the two DAP’s above it was a bit of a letdown. I count this as somewhat of an anomaly since the Zen CAN does sound quite good.



Going into this review, I was faced with another IEM in house at the exact same time. Once that is more expensive as well. I like both quite a lot and they are different enough to warrant a separate look. But, and here it comes, the Legacy 4 competed so well, that I liken this to the entry level IEM from UM or Oriolus. If the entry level IEM’s sound this good, what do the upper, more expensive one’s sound like? Don’t take this wrong. In fact, go the opposite way. If this model, the Legacy 4 sounds so good, do you really need to experience the upper end? This seems to be a facet of manufacturers of late; and that is good.

The Legacy 4 is not without fault (there is no perfect IEM out there, period. Only ones, which could fully satiate your desires...). It could have more bass for my taste. It is amongst the more tip dependent that I have recently had, and this affects placement in your ear and movement. I find with the wrong tip (even if it is my preferred listening poison) you must keep very still, much like Elmer Fudd stated so long ago, “be vewry, vewry qwuiet...we arwe hunting wrabbit.” But I tolerate it because the sound is so good.


Producing a model, which can completely satiate your listening desires at a price that is not that far from “budget Chi-Fi” makes you seriously think that while you could most certainly go further up the food chain, why would you though? And that is the defining decision, which makes me pretty much state that I have a “new king” at the $200 price range, supplanting my old king. To me, the Legacy 4 is so good, that you could define your collection around it and be happy to stay put. You really could. But what is the fun in that?

I again thank Lillian and Linsoul for the support and review sample. The legacy 4 is good and while it could certainly satiate your needs, I for one wonder what the higher ups sound like in the legacy line up. Cheers, and enjoy your listening.

Try different tips, the soundstage may change a little? Though I typically find soundstage to be bigger (than many) and adequate.
Good to know your experiences regarding soundstage. While I like a nice wide (but still fairly cubic and not of the cavernous variety) soundstage; that really isn't the defining characteristic to me anymore. I can live with a narrower stage if I like the tuning. I have heard good things about the Rai Solo, which makes me believe people can look past the soundstage as well. I will also admit that the Legacy 4 is narrower than I would prefer. But the tuning is quite good indeed.

Agreed, the imaging can make up for it maybe?


New Head-Fier
Midsize car with leather seats
Pros: fresh and vivid signature
natural timbre
good technical characteristics
very good allrounder
Cons: needs good mixed music material to shine (not necessarily a disadvantage, as it rather speaks for the resolution of the IEM)

Perhaps a bit too much presence in the lower treble range for some
Rating: 8.8
Sound: 8.7



THIEAUDIO has quickly grown into an established company. Probably the most decisive reason for this is the tuner(s) behind the models, who always has the tonality in mind, but can also technically get a lot out of the chosen drivers. Despite different signatures, the individual models are mostly aimed at the general listening habits without great experiments (I exclude the Voyager 3).
The company (which is run under the patron Linsoul) knows how to convince in almost all price categories from 100$. However, I assume that a budget model (perhaps a single-DD) will be added to the portfolio in the future.

But back to the essentials. The LEGACY 4 is the fourth and currently newest representative of the series, alongside the L3, L5 & L9. Who has been missing with the L3, or L5 some energy in the upper mids and treble, gets this now with the L4. For me, an absolute value and tonal, but also technically a fantastic IEM in its price class.



IEM case in an accessory case (on-ear format), again in a box packaging. Unpacking the LEGACY 4 is a bit reminiscent of a matryoshka. The lush accessory case in particular is very unusual and of limited use when traveling, unless you want to take your portable DAC collection and 10 cables with you. "Unfortunately" the inlay is not removable and so you are somewhat limited in its use (toiletry bag, makeup case, Ü-egg collection...).
Nevertheless, this is of course nice to look at and makes a high-quality impression.

Yes, posh is the way the world goes down. The tip selection (exclusively silicone of one type in 3 different sizes with 2 pairs each) is presented impaled on a metal plate. The silver-plated cable is in the IEM storage case, along with a SIM card remover for dip switch adjustment.
The 8-core cable is quite good, though I found the cables of the L3 and V3 more satisfying to the touch. Likewise, I would have liked a 2.5mm (balanced) cable with a 3.5mm adapter. In this case, it is "only" a standard 3.5mm stereo connector. However, that can be changed with an extra $54, which is a bit high for my taste.

The L4 has a classic custom-style design and is extremely comfortable to wear. In addition to the ergonomics, the low weight and the size are also beneficial. Compared to the Moondrop Blessing 2, for example, it has much narrower sound openings and doesn't seem as bulky, which makes it suitable for smaller ears as well. The faceplate and body can be customized for a surcharge.

The workmanship is without complaint and the isolation is also quite good. However, you can't expect absolute shielding, since outside noise can penetrate better through the air vent for the bass. Nevertheless, the isolation is in a good range, even without music.

The L4 can also be made as a custom (CIEM). For this service, you pay $70 more if you can provide an ear impression.



The Legacy 4 has a warm fundamental tone with warm/neutral mids and slight brightness in the treble, which gives it a fresh but relaxed signature that takes its cues from HARMAN. In other words, a tuning suitable for the masses, which turns out to be a sovereign all-rounder and also invites closer listening due to the good technical characteristics. The description of the sound is based on the switch setting 0|1.

The low frequency is covered by a dynamic driver and scores with an extended bass and punch. However, it doesn't hit dry and too hard, but retains a certain softness that reflects a natural response of the bass and doesn't seem anemic or sterile. On the contrary, the bass adds warmth to the signature, which, however, does not contribute to falsification, but rather creates more of a natural body and solid foundation. The bass can provide fun depending on the genre and mix, but never overdoes it and does not fall apart even in faster passages. Still, I would like to see a bit more texture and precision. The low end is very reminiscent of the L3, though the L4 sounds a My tidier and tighter.

The similarity to the L3 cannot be denied in the mids either. Here, the bass (DD) harmonizes well with the midrange (BA), resulting in a warm/neutral tonality.
Since the L4 has a bit less level in the upper bass in contrast to the L3, the mids seem a bit clearer and not quite as voluminous, but this is also strongly influenced by more level in the upper midrange. This makes them sound a bit fresher and a bit more in-your-face, but without becoming garish or unpleasant. I particularly like the midrange's balancing act between assertiveness and simultaneous relaxation with tonal accuracy. Instruments sound natural and voices have a correct timbre, even if they sound perhaps a tiny bit brighter than neutral.

This is due to the treble, which has a peak just around 5 kHz that gives voices presence, which might be too much for some. However, this falls within an absolutely tolerable range for me. I like the gained effervescence and also the created airiness. Since the treble does not veil very much, the music should be mixed well, otherwise it can quickly become a bit tinny with cymbals, for example, and the treble sounds more unclean than it is. As I said, however, this is then clearly a weakness of the music material, since the L4 is quite uncompromising in the high frequencies. It lacks a bit of extension and level in the overtones, but still the brilliance does not come up short and will leave if only absolute treble fanatics with a disillusioned look. Personally, I even find the treble to be the absolute strength of the L4, which basically also sets it apart from the L3 and gives it more added value.

Technically, the L4 is very solidly positioned and more than commensurate with its price tag. It creates a light out-of-head experience with very good separation and layering. Listening to music with the L4 is fun not only because of the good tonality and punchy foundation, but also because of fine details that are very easy to locate and always keep you entertained and interested. The 4 drivers harmonize with each other and can play to their respective strengths. Yes, you can hear that BA drivers are responsible for the midrange and treble, but not because this area sounds unnatural, but just the advantages of the driver type come to the fore.

Switch - the L4 is equipped with 2 dip switches on the housing. Similar to the L3, however, the first switch is practically useless and a sonic change requires some imagination.
The second switch, however, makes an audible difference and is a nice tool to modify the sound according to one's preferences. I personally favor the 0|1 setting, as it brings more balance to the signature. In the 0|0 setting, the L4 goes more in the "V" direction with more level in the bass and treble. For me, it then becomes slightly unpleasantly spiky and the mids recede a bit more into the background. Nevertheless, this setting can provide added value for rock music, for example.



For me, the Legacy 4 is an IEM that not only plays tonally on a very high level due to its, to say the least, balanced mainstream tuning with a slight brightness, but also doesn't have to be accused of much technically. Whoever decides to buy the L4 will also have a lot of fun with the IEM beyond the new-toy bonus, because in addition to its all-rounder qualities, it also brings the necessary pinch of sensitivity to make audiophile hearts beat faster.
The L4 is for me the symbol of the middle class with features of the upper class. Of course, you won't find absolute resolution, scalpel-sharp separation or excessive extension at both ends in the L4, but that would also be a (wishful) TOTL-IEM, which is much more expensive.
What must be credited to the L4, however, is the authentic, refreshing and natural playing style with fine details and level stability. Tonally without gross blunders, even if certainly not neutrally tuned and in addition an extremely long-term reliable IEM, which delivers an outstanding overall package and brings out the clear advantages of a hybrid IEM.

If you like it a bit more crisp and technical and want to focus more on neutrality instead of musicality, you should take a look at the SEEAUDIO YUME in the same price range, which is also an amazing value.

More reviews: CHI-FIEAR
A New $200 Benchmark
Pros: Great mids tuning
Tight DD bass
Unabashed treble
Great accessories and packaging
Awesome cable
Energetic signature
Cons: Tiny treble peak that some might find harsh

After the release of the Thieaudio Legacy 5 a few months ago, I could've sworn I saw a comment on the Linsoul Discord saying that there weren't any more plans for a new IEM from Thieaudio for a while. Well, here we are with the Legacy 4. At a $200 price point and a 1 DD + 3 BA driver setup, it lands right between the older Legacy 3 (1 DD + 2 BA) and the newer Legacy 5 (1 DD + 4 BA). What makes the L4 interesting is that it takes the concept of tuning switches from the L3 but builds off the design philosophies of the L5. It also introduces a new DD that's supposed to be an upgrade from the one found in the L5 and Monarch/Clairvoyance. Thus, the obvious question that immediately follows is: is the L4 better than the L5 for $50 cheaper? With that in mind, lets take a look at the Thieaudio Legacy 4.

Disclaimer: The Thieaudio Legacy 4 was provided to me by Linsoul in exchange for this honest review. I am not or will be compensated in any other way.

What's in the Box?

I must say, I am extremely impressed with package that the Thieaudio Legacy 4 comes in. You get a massive carrying case that holds the IEMs, tips, and IEM case. This case is made of rather decent material and does NOT feel cheap at all. You get 6 sets of generic S, M, L tips. The smaller rectangular IEM case is very similar to the larger overall case and houses a 2-pin cable. The inside of this IEM case even has a soft furry lining and a pillow-like bed. To be honest, I can't help but think that Thieaudio probably could've saved everyone like $10 with simpler packaging but hey, this unboxing experience was a welcome step up from your standard cardboard box.

The 2-pin stock cable that comes with the L4 has pre-molded ear hooks and is very good. Soft, pliable, light, little cable noise, little cable memory. Every cable should aspire to be at least of this quality. The fit and comfort of the L4 is excellent as well. The shell is small and very light. I get a tight seal that causes a little bit of DD crinkle upon insertion. There is a lack of a nozzle lip on the L4. Combined with the tight seal, sometimes ear tips get stuck in my ear when I try to remove the L4. It's a minor annoyance, but an annoyance nonetheless. Finally, there are two tuning switches on the L4 for a total of four tuning options. You will have to use a SIM ejector tool or similar as these switches aren't accessible otherwise.


My first impressions of the Legacy 4 were positive. As expected from the newer Thieaudio IEMs, the mids tuning is on point. The real difference maker is the new DD. Compared to the L5, the bass is much tighter and responsive. Coupled with a forward treble, the Legacy 4 sounds lively. From this standpoint, I think the L4 is differentiated from the L5 which has a more relaxed and laid-back signature. I find myself more inclined to listen to energetic tracks with the L4 than slower ballads.

Tuning Switches:

There are four total configurations for tuning the Legacy 4. I don't know why Thieaudio insists on using ON and KE as names for the switches. So I'll opt for a standard 00, 01, 10, 11 system.

Interestingly enough, the first (ON) switch ostensibly has no effect on the frequency response. I was pretty surprised by this as I was ABing the switch quite extensively before graphing and thought that it affected the bass by a little bit at the lowest registers. For me, when that switch is up (0 position), I felt that the bass right at the interface between subbass and midbass had a little more of a thump to it. By contrast, in the down position, the bass was cleaner and better defined. But looking at the graphs now and trying to AB it again, I feel like I can hear that difference but it's diminished enough that I'm starting to wonder if it was some sort of placebo effect in the first place. Ah, the wonders of psychoacoustics.

The second (KE) switch has a much more straightforward dip in the mids. Though it looks pretty significant on the graph, it's a lot less drastic in practice. The biggest deviation is about 2.5 dB in the mids at about 500 Hz. I'm a lot less sensitive to changes in this part of the audio spectrum compared to say, the upper mids and treble. Thus, this switch adds a noticeable but subtle mild V-shapedness to the L4. What's also interesting is that if you normalize the curves to the 1 kHz mark, they look extremely similar. But since I didn't change my volume between AB testing, the un-normalized curve is how I interpreted it.

I prefer it in the up position and will move forward with this review using the 10 setting. Just keep in mind these two points on the tuning switches if you want to translate my review to a different setting.


The bass of the L4 is reasonably elevated to provide a consistent bass presence without being overbearing. It extends nicely to give subbass rumble. But really, the L4 is more of a midbass IEM. It opts of a controlled presentation rather than a booming bass response. The bass quality in the L4 is a breath of fresh air from the slower, tired feeling DD of the L5. The driver is fast and punchy. It feels tight and raring to go. Resolution is solid with a nuance that isn't smoothed over like other DDs. Instruments are well defined and the L4 particularly shines with the bass guitar and kick. If I had to nitpick, I'd say I wish the bass had more impact and better texture. But given the price point and overall quality, the L4's bass is plenty enjoyable.


I'm not sure how the 1 DD + 3 BA is exactly configured on the L4, but I can say that I don't notice any oddities in the transition from the bass to the lower mids. It sounds natural and done cleanly without sloppiness. There's not much to say here other than it sounds great on my 10 setting. The mids tuning is comfortable and just feels right. There's a very good balance between instruments and vocal presence. Vocals never fight for space on the L4 and takes a clean center stage. Try as I might, I can't really think of anything to nitpick here.

But if you were on the 01 or 11 setting, the mids do change a little. It becomes thinner and less full. With instruments, I barely hear a difference. But with vocals, the lower harmonies sound a little sucked out. To be honest, it's pretty subtle and if I didn't actively AB test it to see which I preferred, I probably wouldn't have cared if I was just using the L4 casually for commute. At any rate, I strongly suggest that if you do get an L4 to try it for yourself and see which you prefer.


I really like the treble of the L4 but those treble sensitive should be a little wary. It's well elevated and doesn't try to smooth over or hide anything. However, there is a small peak right around the 5 kHz that can occasionally make music sound a little harsh, depending on how well the track is recorded anyway. Thankfully, I don't hear any vocal sibilance despite that peak. This bit of treble elevation does make the lower treble of the L4 sound crisp. As the rest of the region is similarly elevated, decay rings out naturally.

In fact, other than the slight brightness, I'd say the treble of the L4 represents a starting point of what a well tuned treble should look like. It passes my hats/cymbals tests rather easily and avoids a lot of the common pitfalls that IEMs have in the treble. It doesn't try to hide the lower treble nor does it have major dips and valleys that throw the timbre off. The only thing I'd say is lacking on the L4's treble is upper treble extension for air/sparkle but you only ever truly see that on a small subset of IEMs anyway.


I'd say that the soundstage and imaging of the L4 is on the good side of average. There's a bit of depth, not a lot a height, and decent horizontal width. Imaging is relatively nuanced within that stage. Layering is constrained due to a lack of perceived depth but separation isn't an issue thanks to how well defined instruments are with the L4. Resolution is solid for its price class. Altogether, the L4's technical performance here is what I would consider the benchmark for $200.

Now I will note is that the Legacy 4 does sound kinda compressed. But when I compared it to the L5 or other IEMs I had lying around, they performed at about the same level. I think it's less about the L4 being compressed but rather the fact that thanks to the L4's energetic tuning, it amplifies this limitation commonly found on IEMs.

Should You Buy It?

Yes. It's a very good IEM. As strange as this may sound, I think of the Thieaudio Legacy 4 as an upgraded version of the Tin HiFi T2 Plus. Beyond the technical improvements, the bass is fixed, the tonal balance of the mids are improved, and the L4 retains the brighter treble tuning. With the ~$100 price range being dominated by the Tin T4, Moondrop Starfield, and Etymotic ER2, it's nice to see an IEM that anchors the $200 price point. That said, if you're happy with the T4/Starfield/ER2, I wouldn't upgrade to the L4. It's better if you're coming for the budget $50 class of IEM like the aforementioned T2 Plus.

For the most part, I think you can safely skip the Legacy 3, save a bit more cash, and opt for the Legacy 4 instead. Whether or not you should get it over the Legacy 5 is a bit of a tricky question. I think for most people, the Legacy 4 should be the one you get. But if you specifically want a more laid-back tuning for listening to music as you work, the Legacy 5 remains the better option. I find the L4 to be a great commuter IEM but if I'm working, it's a bit too energetic for me.

Overall, the best thing I can say about the L4 is that I really did enjoy listening to it over the course of this review. I try to spend a couple of weeks listening to gear before I review them and sometimes it's a pain to listen when I'd rather spend my time with something better. With the L4, it was easy to reach for it and enjoy music. For now, at the $200 mark, I'm satisfied with the Thieaudio Legacy 4. I do have the Seeaudio Yume in my review queue, which is another $200 IEM that's been gaining some traction, so I look forward to seeing how that stacks up.

Written by Fc-Construct


New Head-Fier
Pros: Energetic and Lively, Fast and Detailed Bass, Great Technicalities and Extension, Accessories and Cable, Great Fit
Cons: Mid-Bass to Lower Mids hollowed out, Upper Mids and Treble Potentially Fatiguing


Disclaimer: This review set is a demo set graciously lent to me by a friend from his personal collection. This review is written of my own accord and all thoughts here are my own.

In a such a short span, Thieaudio has released its 4th IEM in the Legacy series, the Legacy 4. As indicated by its name, it is a hybrid with 4 drivers in a 1DD+3BA configuration. The Legacy 4 sports a new dynamic driver developed in-house by Thieaudio and as expected, has quite a different bass response when compared to the other IEMs in the Legacy 4. Read on to find out more about how the Legacy 4 spices things up.

Accessories and Build Quality (Score: 9/10)

Build quality of the shells is once again stellar from Thieaudio. The faceplate design is intricate and gorgeous without being too gaudy. This is complemented with a smoke shell that allows you to admire the drivers within.

I especially like how they have moved away from the QDC connectors which tended to crack.


The cherry on top of the cake is really the packaging and accessories. The IEM comes in a huge zipper case containing the IEMs, tips and cable, and another small zipper pouch. This has got to be the most comprehensive set of accessories I’ve seen for an IEM at its price point.

The Legacy 4 also comes with a new silver 2-pin cable with a 4-wire braid. Although thinner than the previous 8-wire stock cable, it’s sleeker and much more aesthetic.


Fit (Score: 9/10)


Fit is great for smaller ears. The shell is overall quite slim and manageable, somewhere in the middle of the Legacy 3 and 5. I preferred the fit of the Legacy 4 has it has a longer nozzle than the 3, providing a much more secure fit. I also did not experience any driver flex.

Sound (Score: 8.6/10)


I used the Down-Down (DD) switch combination for my review


The frequency response for all the switch combinations

Sources Used
  • Hiby R5
  • Lotoo Paw S1
Albums and Tracks tested with
  • Bon Jovi – Living on a Prayer
  • Spinners – Essentials
  • Itzhak Perlman – Paganini Violin Concerto No.1/Carmen Fantasy
  • Michael Bublé – To Be Loved
  • Robin Schulz – Sugar
  • The Lumineers – Cleopatra
  • The Police
  • Tears for Fears
  • Eurythmics
  • Boston Symphony Orchestra
  • Tokyo Kosei Wind Orchestra
Bass (Score: 9/10)

Having heard the Legacy 3 and 5, the bass on the Legacy 4 is quite refreshing. This is apparently due to Thieaudio’s “new in-house 8mm poly-membrane dynamic driver”. The bass emphasis leans more towards the sub-bass with incredible extension and detail retrieval. Listening to songs by The Police like “Every Breathe You Take”, drums are extremely fast and tight with little to no midbass bloat. There is a very nice punch in pop and rock songs.

However, on more instrumental tracks like orchestras and wind symphonies, the snappy bass response and quick decay work against it, where the sound becomes a little dry and sounds less organic.

Mids (Score: 8/10)

There is a region stretching from the Midbass to the Lower mids which is left sounding a little hollow. This impairs the overall coherence of the sound overall but also contributes a sense of improved clarity and detail retrieval. Listening to songs by Michael Buble and The Lumineers, the L4 takes out a bit of the soul and emotion in the vocals in exchange for a more sterile presentation.

That said, the energy levels are off the charts in the upper mids and lower treble. Electric guitars sound truly electric, and synths create an intensely lively atmosphere that truly transports you. I thoroughly enjoyed the Synths and beats on “Sweet Dreams are Made of This” by Eurythmics and tracks from Tears for Fears.

My biggest complaint about the upper mids would be that they are a little too intense and fatiguing after a while, and instruments like trumpets and horns sound a little thinner and shriller than they should. This is said from my personal experience of playing in wind orchestras and being regularly exposed to how these instruments sound in real life. It isn’t to the point of sounding metallic but strays from the natural tonality.

Treble (Score: 8.5/10)

I don’t have much to comment on for the treble, apart from its precision and accuracy of it without it coming across as harsh. There is a nice shimmer to crash cymbals but I could tell it is a little pushed back and not to forward sounding which was a nice touch. The upwards extension is rather well done despite the lower treble emphasis. I personally would have preferred a little less of that emphasis for a more comfortable listen.


Out of all the Legacy series IEMs I’ve tried, the L4 has the most V-shaped tuning. It is very competently tuned and has the technical chops to back it up. The biggest difference I’ve noticed is the bass response and it is a welcome switch-up from the 3 and 5. Another standout point I noticed in the L4 was its imaging. It was very well done and made everything livelier and more engaging.


VS Moondrop KXXS (Review here)

Given their similar price points, I thought to make a quick comparison despite their different driver setups. My first observation was how the bass detail retrieval on the Legacy 4 blows that of the KXXS out of the water. The KXXS has a slower decay for a richer sound whereas the Legacy 4 punches hard and fast. As for the other aspects of sound, they are both respectable performers in terms of their technical capabilities with the Legacy 4 having the edge in technicalities and the KXXS having the better timbre of the two.

VS Legacy 3 (Review here)

Comparing the Legacy 4 to its younger sibling, it is a very significant upgrade in technical ability, especially in the bass and treble detail retrieval. However, I would say that despite their similarities in appearances, they have a very different target tuning, and the Legacy 4 is not exactly an immediate upgrade over the Legacy 3.

Despite the significant improvements made, there are still aspects of the Legacy 3 that I wished to have seen in the 4, like its lush and fluid mids that seamlessly connected and synergised with the lower frequencies. The L4 seems a little disjointed in its area. The L3 is also an easier listen for longer listening sessions, but take note that this may all purely be personal preference and YMMV.



The Thieaudio Legacy 4 is a very matured product with a competent tuning. Thieaudio has grown a lot since its first few IEMS such as the Voyager 3. It really shows through the little things that they pay attention to such as the packaging, design and build. The Legacy 4 indeed switches things up in the Legacy lineup such that there will be a Legacy for everyone’s tastes at various price points and this inclusiveness and variety combined with its variety it what makes Thieaudio IEMs so enjoyable to review. I do hope that Thieaudio does not despite the back to back releases as I have a one or two bad experiences with QC of my own with them. That said, I do look forward to more releases from them and although the Legacy 4’s tonality and tuning may not so much be to my tastes, I do see it being a comfortable recommendation for many especially at its price point.


1000+ Head-Fier
Heavy hitter for its price!
Pros: Fairly enjoyable tuning. Small lightweight design. Doesn’t need much power. More of a safe tuning with an upper mids boost.
Cons: More of a safe tuning with an upper mids boost. May get sibilant for some. Stock tips are meh. Doesn’t scale far with better gear.

My two go to IEMs in the $100-300 range are the FiiO FH3 and the Ikko OH10. I haven’t had the chance to check out the other legacy lineup but I was interested in trying the Legacy 4 that comes in right at $200. On paper these look like a pretty nice Hybrid IEM. It has a single DD and 3 BA drivers which made me think this would either be tuned for a decent neutral sound or possibly a brighter sound. One neat thing about the L4 is that it can be customized on linsoul’s website. This means that the options for different faceplates and shell colors are available to really make the IEM your own. You can also get these custom fit if you have impressions as well. Let's see where the L4 sits in the rankings of my two favorite IEMs in this price range. Oh and I’m gonna refer to these as the L4 for the rest of the review.

Quick shoutout to Linsoul for sending me the Legacy 4 to test and review. While I always appreciate the chance to test and review products sent in from manufacturers, it never affects the rating of my review.

The Legacy 4 can also be picked up from the Linsoul store here:

Onto the review of the Legacy 4! My personal preference is a dynamic hybrid iem where I get good hitting bass and have a brighter treble with decent mids. When it comes to an over ear headphone I prefer a spacious sound with a deep low end, the mids to be more forward and the highs to be a little bright with some sparkle. I listen to a lot of genres but I hover in the classic rock, blues and edm music with some rap here and there.

Gear used
IPhone 12 pro with headphone adapter, iFi hip dac, Lotoo PAW S1, iFi micro iDSD Signature, SMSL SU-9 feeding the SP400 amps.

Looks and fit
I really like the look of the stock L4. The black transparent shell with the swirls on the faceplate gives it a really nice look. The fit was fantastic for my ears. The nozzle is fairly average in length and has a decently wide lip which means it wasn’t a huge pain to get different tips on the L4. The IEMs are fairly small vs something like the FH3 and OH10 so I was surprised when I first saw them when I opened up the box.

Packaging and accessories
For how small the IEMs ended up being, I was surprised by how big the box was. Once you open up the cardboard box, you get a fabric hard shell case. Inside that there are the IEM’s, a smaller travel case, tips and the stock cable. While I liked the travel case and cable, I didn’t really care about the stock tips they included. I think a smaller box would have been fine for the packaging of the L4. That being said, for someone new to IEMs, this may seem really extravagant and might give off that feel of “super premium”.

These final impressions were done off a mix of the iFi hip dac and the SMSL SU-9 connected to the SMSL SP400. These are what the Legacy 4 sounds like to my ears. Things like ear tip selection and DAC/amp selection will produce different results and impressions vs what my ears hear on my specific gear.

The low end is slightly elevated but I wouldn’t call this set warm at all. When the music calls for it, the impact and rumble is pretty good. It’s just a hair under what I’d prefer from a hybrid IEM but it sounds clear and accurate without bleeding into the mids. Speaking of mids, the L4 has a boosted upper-ish to lower treble boost that I found fairly noticeable. While I don’t mind this type of tuning, I found that at times the L4 could sound a little sibilant with vocals and lean due to a neutral sounding low end. The upper frequencies feel fairly relaxed. With how the upper mids are tuned, I have to listen at lower volumes to avoid sibilance so the highs don’t get much of a chance to really shine. While this tuning isn’t 100 percent my personal tastes, I find it very good for an IEM like this in this price bracket. It will give off pretty good sound quality for most listeners I think.

Soundstage width and depth are fairly average here. Things feel closed in for the most part. The imaging was pretty good for how average the stage is. I was able to pick out the placement of specific sounds and I was overall pleased by the imaging.

Tuning switches
I didn’t notice any difference in tuning combos other than one main effect. When I had the 1st switch “off” and the second one “on”, there was a light yet noticeable bump to the lower mids-lower treble. This made for a little bit of a exciting sound signature but I personally preferred the “default” tuning.

Cable rolling
I normally love to cable roll and I threw a few cables at the L4. Mostly to see how the L4 would do when run balanced. Overall I didn’t notice any real difference in going balanced and I actually hit a wall with source gear pretty quickly when it came to how the L4 scaled. The Legacy 4 isn’t very hard to drive so I’d say only grab a different stock cable if you want something that looks/feels different.

Stock cable
The stock cable is acceptable IMO. I don’t really like it as it looks like it has a somewhat loose braid. I would have preferred the cable to be braided a little tighter. The cable didn’t pick up any microphonics as I walked around so I’m happy with that. I think the stock cable is perfectly fine for everyday use and personal preferences will be the deciding factor when it comes to replacing it or not.

Tip rolling
The stock tips are a boring standard set of tips. No foams or anything interesting are included. I used a variety of different tips and ended up going with the Spinfit CP360 for my final testing. Big bore tips enhanced both the mids and treble but things got a little too bright at times for my tastes. The small bore stuff killed a little of the soundstage but brought out a warmer sounding IEM.

IEM comparisons

FiiO FH3

The L4 has a better low end and better midrange over the FH3. The FH3 however has a better treble response. I pick up more details from the FH3 but I enjoy the tuning of the L4 over it. Staging is about the same between the two and I found the L4 more comfortable in my ears for long sessions. I think both are fantastic options but I’d personally choose the L4 over the FH3.

The OH10 has a much thicker and meatier low end response. The L4 sounds fairly lean when switching between the two. Mids are a mix as the warm tones of the OH10 and the accurate mids of the L4 go in opposite directions. The highs are about the same between the two. The OH10 has a slightly splashy top end with more sparkle at times. The soundstage is much wider on the OH10. Depth is about the same between the two. Overall I think it comes down to personal tuning tastes between picking from the two IEMs. I personally like the tuning of the OH10 but for more accurate listening I think the L4 is a great option. The L4 is also way lighter than the OH10 which makes for less broken seals when moving around.

Lightning headphone adapter
This was actually a pretty good pairing. Things sound a little relaxed and a little less engaging overall but I can recommend just using the headphone adapter for this IEM and not feel bad. I would recommend even something cheap that puts out a little more power than the stock apple adapter.

iFi hip dac/ Lotoo PAW S1
Both the hip dac and S1 bring different things to the table in terms of their “house sound” before any EQ or device specific “boosts”. The hip dac pushes out more power but the L4 really doesn’t need the extra power and I only made it to about 11 O’clock via single ended before it was too loud. The S1 has a much wider range in volume so going up or down a few numbers in volume doesn’t change things drastically. I’m pretty confident that I could easily murder the L4 off the hip dac if I accidently hit the high gain button or accidently adjusted the volume too high. Something to think about if looking for a portable source dongle. Overall things sound faster between the two devices when paired with the L4. The hip dac has a slight warmth with better dynamics. The S1 gave the warmest sound with a nice wide stage. Both are great options for the L4.

I actually hit a wall with sound quality differences with the NEO and SMSL pairings. Not all IEMs scale as you go up in the quality of gear and this was one of those IEMs. I couldn’t tell a difference between the hip dac and any of my better desktop gear when using the L4. Not a bad thing and this keeps someone from having to invest in more expensive gear to drive these IEMs.

Amping thoughts
This was easy to drive and it didn’t scale at all past the portable gear I had. As such, I’d say something like a Lotoo Paw S1/other portable device or a desktop “stack” in the $200 and under range will feed the L4 extremely well.

Overall thoughts
The L4 was a very nice IEM to use and I enjoyed testing it. While I didn’t see a need to replace my daily driver OH10 for listening in bed or on the go(wired), the L4 found its calling paired to the FiiO UTWS3 wireless adapters. This is my go to for work or walking around outside for exercise. Since the L4 doesn’t need much power, I can reach higher volumes on the UTWS3 without cranking the adapter's volume up. I think this sounds better than the FH3 from FiiO and I’d say it’s a different flavor when compared to my OH10. The THIEAUDIO Legacy 4 will get a recommendation from me as it’s easy to power, super comfy and has a pretty good tuning as well. After trying the legacy 4 I'm now interested in checking out some of the other THIEAUDIO IEMs. Thanks for reading!
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Headphoneus Supremus
Top Value
Pros: Great tonality/signature
Lightweight/perfect fitting universal shells for me
Great looking cable and accessories
Improved bass quality with new DD
Good resolution
Cons: Slightly brighter lower treble may bother some over time

I thought Thieaudio was going to slow down on the releases of their in-ear monitors but then they come out with the Legacy 4. This four-driver IEM comes packed with a single dynamic driver and 3 balanced armature drivers and retails at $195, placing it in-between the Legacy 3 and Legacy 5, both of which I've reviewed this year.

The product was sent to me by Linsoul, who are the makes of the Thieaudio brand and are found at


The Legacy 4 comes with a new dynamic driver that has not been used on previous Legacy series IEMs. This new DD is perhaps a welcome change as one of my biggest negatives with the previous Legacy 3, Legacy 5, and Monarch/Clairvoyance, were mainly triggered by the lack of resolution and softness of the bass range.

In addition to this change, the packaging is all-new, again! It seems like every unit I've gotten has come with a new unboxing experience and this one has been my favorite yet. The L4 ships in a large nylon zipper case, which when opened, houses the IEMs, matching smaller case, and tips in their own small compartments within the larger case.

The cable included is also my favorite of the ones Thieaudio has included in any of their sets to date. This one is white colored, and is braided with a soft sheathing material that has a lightweight, but durable feel to it. It's extremely easy to wind and unwind without tangling, and is very maneuverable. I also just like the overall simple modern look of it.

The shell design is small and petite, much like the Legacy 3 in size and shape. The faceplate art is available in only one swirl pattern that features a mix of blues, yellows, and orange within in a semi-translucent black shell. There's a single vent on the shell, and it also features a pair of tuning switches which add or subtract mid-range to the IEM in what seems like just 2 configurations total in my measurements.

Sound Impressions
The Legacy 4 has a well-balanced signature that does stray a tad bright in the lower treble regions that I think some may find fatiguing over time, but this also provides a clean clarity to the overall sound. It surprisingly has good extension for this price class and I find it sounds like a better tuned and more technical Moondrop Kanas Pro or KXXS, and is priced just a few dollars more than those well-received IEMs.

The new dynamic driver which handles the low end seems like a large improvement over the previous dynamic driver found on all the previous Thieaudio IEMs. This new one has better microdynamics allowing for better punch and resolution, and does not fall behind the quality of the BA drivers as much in that department. It still isn't the best dynamic driver I've heard in an hybrid IEM (MEST!) but its quite enjoyable for this under $200 price point.

It's no longer blunted and smoothed out, and I don't jokingly call it the Blon DD anymore. It's also a marked improvement over the Moondrop KXXS and Kanas Pro low end sound. Those two are a single DD which handles the entire frequency response.

The mid-range of the Legacy 4 can be altered depending on the dip switch choice. While there are technically four different combinations of switches, in my testing and measurements, only two configurations make a difference. If you leave the RIGHT side on or off -- in other words, OFF-OFF and ON-OFF are the same, and ON-ON and OFF-ON are the same. This is similar to the Legacy 3, where they could have just kept one switch and saved time and effort.

The midrange does change from a flatter and thicker sound to a more recessed sound that changes the overall sound from a mild U-shape to a mild V-shape signature overall. I found that I enjoyed the Right ON (flatter mid-range) more for most things, though with rock music and some more pop genres, the RIGHT OFF signature worked well as well. I would also prefer this for movie watching.

The treble range on this unit can get a little hot. It is just a tad brighter than my preferred sound signature, but only slightly. For those who are familiar with the Moondrop Blessing 2, it is pretty similar in that type of level of treble. That said, I do find this one behaves a little more so, by being more treble tame, than the Blessing 2 in terms of overall brightness, and it does not sound quite as lean, mostly due to the fact that it has a bigger bass shelf.

That said, when I listen to music with a lot of stringed twangs, those instruments (primarily guitars) can come across quite forward and tizzying (is that a word?). Some piano notes came across this way as well, with strikes coming in a tad sharp at times. I wouldn't say I found these fatiguing, but I am one is quite accustomed to listening to slightly brighter than neutral gear, and the peaks in the 5KHz region is common amongst some of the gear I own and listen to regularly. For those who are sensitive to this area, it may be something to be wary about.

Treble extension is quite decent for this price range, and specifically I am going back to talking about its contemporaries here -- the Moondrop dual, and even the Etymotic series, which are similar in tuning and capability. Both the Moondrop and Etymotic series sound just a bit flat and missing full treble extension. The Moondrop twins are more guilty of this however. With the Legacy 4, it does extend treble, but maybe not with the same amount of air and shimmer as some other gear I've heard at higher price points. That said, I am perfectly pleased with this amount for price range and I am quite content with the overall sound in general.

I've spent some time talking about it with regards to its competition, but how does it stack up within its own family?

I gave the Legacy 3 are mostly supportive and recommendation earlier this year and even bought the universal and custom versions. It's a great deal for the price, however my biggest complaints with it were its lack of technical capabilities. This had a lot to do with dynamic driver sounding very mushy, but it also had a very forward and 2D sound to it. This means, I never really felt the depth was there, and it lacked good imaging and instrument separation.

The Legacy 4's improved driver configuration seems to help out a lot here. While the sound signature is similar, the L4 does not have as much issues with mushy bass resolution, and it has a major upgrade to the soundstage and imaging. The resolution is overall much improved on this set and I would highly recommend someone who is thinking what to get between the two, that its well worth the extra $70 to upgrade to the Legacy 4. The L3 is a little more laid-back and pleasant sounding though, and should be less fatiguing due to its tamer treble response and it does not have that sharper 5KHz sound to it, but it does lack a little bit of the airy treble that I like about the L4.

When we talk about the next one up the price list, it gets a little more interesting. The Legacy 5 is priced at $50 more than the Legacy 4 and adds an extra BA driver to the count. It still uses the older DD though and that is obvious as my major complaint with the Legacy 5 was, again, the mushy, blunted and lower quality bass region. The L5 is also a more warm and lush sounding IEM, with a significantly tamer and thicker sounding mid-range and treble. It's full-bodied in everyway, while the Legacy 4 sounds quite lean compared to it, and has an airier overall sound.

The L5 isn't as bad in the major technical departements as the L3, but I'd say the L4 is on-par and if not surpasses the L5 in every category -- soundstage, imaging, resolution, texturing and layering. I may give the L5 a nod for coherency, because I do feel the sharper BA sound in the L4 makes it sound a little disjointed from the low end DD.

Finally, many have asked how this stacks up to the Monarch and Clairvoyance -- the twins that I believe define the capabilities of Thieaudio. Both of these have well-thought-out tuning and have solid technical capabilities. I think these two still stand top of the Thieaudio brand that I have tried. I have not tried the Voyager 14 and Legacy 9 yet, so keep that in mind.

While the Monarch and Clairvoyance use that old dynamic driver that I did not like, there are a set of BA drivers that are also used down-low to help keep resolution at a good level on these two. Both the Monarch and Clairvoyance have improved resolution and don't have as a fatiguing sound, though the Monarch is a bit shouty in the 1K range, which may affect some.

The Legacy 4 has just a slightly fuller sound in the low-end, but it does have a brighter treble region, and some may not like that. Again, there's an emphasis in 5KHz range, so it'll provide a lot of presence to guitars and strings for the music I listen to.

The Legacy 4 is yet another solid addition to the Thieaudio lineup that is continuing to grow and most of the ones I've tried are well-tuned and fit solidly within their price points, except perhaps the Voyager 3. I have got to say that I am impressed with this whole thing, and they continue to up their game in both sound capability, and also the entire package, which is full of accessories and a unique and meaningful unboxing and package of tools to use.

This one definitely competes in its price point and will get a recommendation from me. It's enjoyable all-around, but it does have a little brighter than neutral treble, so just be mindful of that when considering products with it.
Well rounded review, thanks for covering the effect of the tuning switches.
@aptquark I have not heard the BElieve. It looks promising though.
Thank you.


Headphoneus Supremus
Pros: World-class, fast articulate bass response
A detailed, deep and correct bass ability
Beautiful imaging, separation and a soundstage.....that’s wide, tall and thick
Cohesive, even and correct frequency response
Comfortable physical shape and size
Exciting and complete treble and midrange character
Fun, yet accurate sounding
Smooth and balanced
Mature and completely competent tune
Best $ value of the year
Correctly plays all musical genres I’ve tried
Cons: Nope
Linsoul Thieaudio Legacy 4 Hybrid Universal IEM

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Price $195

In Short:
1) New single proprietary 8mm polymembrane DD added in contrast to the Legacy 3 and Legacy 5 10mm DD

2) New dual BA custom made Bellsing/Linsoul tweeters
3) Single Knowles ED29689 BA for midrange
4) Rumored as “best balanced” of Legacy Series

5) Rumored to contain improvements in tuning resulting from public-feedback on flagship Monarch and Clairvoyance IEMs

Just the concept of Thieaudio 3D printing up new IEM models as fast as magazines creates a phenomenon. One group thinks they should only make a few good IEMs; group two already owns the Legacy 5 and 3 and cheers-on this rumored existence of refinement. Since no IEM is perfect, folks welcome a slight reworking......hoping it’s a step in a new direction. Adding words like (never before existing) 8mm proprietary DD bass the fire here. Though keep in mind while the Legacy 3 is offered as a CIEM model, the L5 and L4 are not at this time. Also......the L3 and L5 have color choices, where the L4 comes as a single (groovy) color. So when you order take note the only option would be the 2.5mm,3.5mm,4.4mm extra $69 “EST” cable upgrade. I’ve never used the “EST” myself, but it ends the Linsoul recommended cable.

What if you were a young retailer who learned over time how to generate your very own stock of merchandise? What if such merchandise was of higher build quality......came-off better looking.....and had cutting-edge superior sound quality? Would that be a good thing? Yes it would!

Linsoul/Thieaudio is listening to the community’s feed-back, then catering to the community’s wants and needs. That’s Linsoul. These words describe their new house brand; Thieaudio......a new audio brand becoming quite well-known this year!

This is Linsoul being factory direct and cutting out the middle-guy. But...............what about going one step further and offering stuff your competition can’t offer? Would that be a good thing?

It’s simply old fashion (good) business.

This has been the easiest review I’ve ever written. I got an email asking me if I wanted to review the Thieaudio Legacy 4. They showed-up in a few days; actually 9 days early? So here we are. Later in this review I’m going to go over the history and how Linsoul and their house brand (Thieaudio) got to this point in time. It doesn’t really matter what I write! The Legacy 4 will be ultimately popular regardless of anything I write here. There are no reviews of this IEM on Head-Fi yet. The L4 has just showed up on DROP for $179. It is what it is. It’s popularity will simply be due to its value. A value in tone quality, a value in construction, a value in accessories and a value in aesthetics.
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The L4 is the most advanced and capable $195 IEM I’ve come across......ever! This enigma is a simple progression of Chinese sound quality getting better and better. So it’s just common sense we would arrive here today.....and how lucky we are. :)

People now don’t actually want audiophile reviews. People like anti-audiophile reviews. It’s safe to say only a small section of outliers are audiophiles, yet due to changes in society the last couple years IEMs and headphones are used by the masses. Those folks consider themselves music buffs, or movie on a laptop buffs, or gaming buffs.....maybe YouTube buffs?

Still even if they will not admit it, they are looking for better sound quality. Also the $195 price is maybe the top ceiling of consumer headphone spending. So we can call this area mid-fi......................................but do we really want to call these mid-fi?

Ok, so what’s so special?

There are a lot of great IEMs out there, but we are short on time so.......cut to the chase. Can you tell me what would seem to make this IEM special? I mean what would separate it from the pack? If there was one simple quality that would create endearment upon first listen.......what would that be....and make it short!

  1. In short the L4 offers an incredibly well imaged soundstage.
  2. Within that soundstage shows a charming fast and textured bass response.
  3. The midrange and treble offer a masterpiece in tuning.
  4. Despite being a hybrid it’s cohesive, natural, interlocked and free of any grain.
  5. ...............within that soundstage..........imaging seems to be amazingly positioned forward and back.
  6. And finally, the L4 contains an even and correct frequency response.

Ok, thank-you.

Still.....................I’m a little confused about number 5?

While having an even and correct frequency response is top priority..................after that imaging and positioning create a feeling of realism because each element has its own place, not only side to side but front to back. It’s holographic!

Starting in 2009, the HiFiMan $70 RE0 was my introduction to “hype-train” Chinese IEMs. 9 years later in 2018 the BGVP DM6 renewed my enthusiasm, continuing with the Japan Sony XBA-Z5, XBA-N3 and ultimately the IER-Z1R. If you were to fully grasp my personal sound signature goals you would see why the L4 was love at first listen. Days of looking for bigger balanced DAP power to correct big 10mm DD artifacts are gone. I see the L4 as one of the most balanced sounding IEMs ever............regardless of price.


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Bass Placement:
It’s a charming style of the bass positioning itself on it’s own.........showing where the soundstage (all of a sudden) can reach-out too. It’s the bass imaging that you will always remember about the L4 besides the balance. It may be that bass positioning that has you reach for it across the top of way more expensive acquisitions in daily use?

Literally the only single small red flag about this IEM is a small lack a thickness in places that TOTL IEMs “fill-in”.

Right there. That’s it………..the one single thing the L4 does not do in comparison to TOTL flagships……in black and white. You can stop reading now.

An ever so tiny lack of overall weight/detail-construction in places regardless of what the bass tracks are always doing right. This lack of meaty-ness is not on every song and not all the time. It’s better described as a small lack of information/creation that will be provided normally by your TOTL overpriced flagships. With how the L4 parlays such listenability and perfection of tone beyond it’s humble price point, this slightly technical lack of physicality can be overlooked.

So to boil this down…….it’s an ever so slightly missing delineation and formation of musical elements. Let’s jump to VIDEO-SPEAK here and say the replay issue could be considered standard definition in places where TOTL flagship IEMs are full 1080p/4K all the time. Remember though there are few TOTL flagships this balanced, that’s what this single review is about.

Let’s get real here:

So surprisingly Thieaudio does not disclose the driver size of the $699 Clairvoyance bass dynamic driver? No bass dynamic driver size noted for the $729 Monarch either? We know the L3 and L5 have a proprietary 10mm Nano-Membrane dynamic diaphragm driver. So just for fun let’s say the Monarch and Clairvoyance have 8mm drivers like the Legacy 4? I don’t know, and I’ve never heard the two. We do of course know the secret................the L4 has the exact Monarch treble making the L4 brighter in tone than the L5.

The other confusing thing has been trying to throw rocks at the bass here. I mean it’s suggested that the people who put 10mm DD drivers in IEMs for bass are doing so for a needed reason. It could be thought that 8mm is leaving something out? And while I’m looking for stuff to be negative about, I’m not finding it. I mean there may be just a smidge of loss of physicality in places. There could be just a slight loss of lower lower-sub reaching? And it’s not that there is any kind of disjointed playback like the bass is not connected. Though at this point it would be interesting to read other reviews? But to get real (and in comparison to some of the best bass I’ve heard) there is maybe a slight set back presence at times on some albums, but I’ve had to look for it and it in no way gets in the way of musical enjoyment. I mean for this kind of money? There must be something left out right? Right? :)

There is always the honeymoon phase where an IEM does no wrong then after a while the brain starts to learn elements and pick out ideas which were missed in the early days. Day to day life is built on pure ability where the honeymoon is enjoying a new tone. If that tone is correct or not it ends entertaining none the less. Of course the other side of the coin is the IEMs that never let you down; the ones that just perform due to great ability and skill. After 50 hours of burn-in the L4 started to smooth-out and open-up slightly. Also to me there was a slight, ever so slight maturity of character. Generally though, this is an IEM that’s not going to change drastically after burn-in. This IEM sounds the way it sounds pretty much straight out of the box.


Power Requirements and Cables:
Are you siting down? This is the part of the review that should be written in red ink. Remember all the rabid talk about amp power; the talk of needing 4.4mm balanced to correct 10mm bass issues. History……………it’s history……the long gone past.

I have no idea, I’m not an electrical engineer, I’m a reader and a listener of sorts……but my un-schooled common sense tells me this 8mm DD is easier to drive? Is it what it’s made of? Is it the cross-overs? Is it that this is only a 3BA-1DD IEM? All I can say the L4 just made a geodesic straight line in the epic IEM DD spacetime continuum. We have now entered a new and grand DD era. Gone is the need for power. Gone in the necessity for 4.4mm balanced big IEM amplifiers. Gone is even the need for a fancy DAP; they do add improvements………..though I suspect due simply from resolution adds? Taking the L4 and joining to my humble iPod Touch was the best bass from that device ever. I used the regular included 3.5mm cable. In fact after trying expensive SPC 4.4mm or OCC 4.4mm aftermarket cables, I failed to observe any need? This cable thing ends-up the most confusing part of the L4 straight forward review process. Basically the L4 will show source differences and recording quality differences but put your $160 4-wire OCC Copper Litz cable on and it’s a wash. This may in-fact be a testament as to how great the included standard 3.5mm cable is? I’m at a loss here, yet………it’s all good.

My musical reference on the iPod Touch was the new OST for Star Trek Picard Season One by Jeff Russo.


This modern OST uses a specific orchestrated bass texture which can be a demanding test for some IEM/source combos in playback.

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So, you may have guessed how much I love the soundstage here. While going out far right and left there is still a seemingly correct center too? My favorite IEMs are known for special big and famous soundstage we are again. To start we must talk about the bass soundstage, and it’s the bass reach that’s memorable. Not all the time but those drops that the producers placed in for drama. The tone goes out and underneath while the layers of midrange and treble float on-top doing their own thing.

So to cut this soundstage chapter short I will come up with an emotional way to describe the soundstage. It’s the ooo and ahh soundstage. The soundstage is so well done you simply become surprised even by songs you are playing for the second time in a row. It’s the ooo and ahhh of it all.

The reviewer subjectivity here:
This ends as one opinion. And while I’ve attempted to be as objective as I can, Linsoul/Thieaudio nailed the sound I’m after. So with that special tune comes a loss of ability to truly be objective and realistic. I say this but our little hobby is making profound progress. Even though Moore’s law pertains to computer chip performance, there is a style of progress which parallels it in Chinese IEM sound. Due to this speed of improvement the results are actually unbelievable and unpredictable. Meaning.............I thought this level of ability would be a year from now and $500, and even that was wishful thinking. The future is here and we are living it. Those signposts; you know the ones that inform you where you are, well the Thieaudio Legacy is that signpost. We my friends are here. Linsoul went and listened to consumer feedback and slowly dialed in a masterful tune....we are now entering the golden age of Chinese IEMs. It’s not even fair to try and do comparisons to 2018 Chinese IEMs anymore, IEMs like the Legacy 4 never existed before. And while the Legacy 4 is not 100% perfect, nothing is. Still that doesn’t undermine the fact that this is most many will ever need. It’s all I would ever need almost?

Most of the time during my review process I simply make a list of comparison IEMs. I choose 6 or so IEMs. Typically there would be a few comparable priced IEMs...... a few higher priced and a few lower priced. Let’s save time here. Such comparisons are not needed. We don’t need to waist time and effort here. This IEM is so good I’m pretty sure I simply only have one IEM that’s better and it is $1700.....the IER-Z1R. That’s right, this is a game changer. The L4 will carve a name for itself no matter what; it’s simply not even questionable at all. This is exactly what Head-Fi is all about and the very reason your even here and reading. It’s not even a question of sound signature wants really. Yes, there will always be the bass-head outliers and the treble-head listeners. Still the 80% center of the bell curve will be right at home. This is so well balanced that not only is it the most balanced of the Legacy line, it’s just more likable than most IEMs out there at a wide range of prices.

Though to be fair, even concerning the L4, there will be people that maybe want more bass or more treble or more midrange. That’s the difficult part of subjective reviews....................we all live in our own myopic bubble and value gear in relation to what we like and have a taste for. So with that in mind I’ll simply try and write some notes as to what’s going on.

And obviously take all this with a grain of salt. It’s simply one enthusiast writing about an IEM which is tuned pretty much exactly correct and technically his ears. I’m actually really curious as to how others will review this as I would like to see how they could throw rocks at it. As always before a purchase, read multiple reviews and don’t take one reviewers ideas as what may be exactly true to what you will experience after a purchase. Such a risk is simply the risk of new purchases, yet after a large group report in on quality, then a pretty good idea can be found out and verified....meaning there is a style of truth in numbers.

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The End Goals Here:
The goal of the Legacy 4 was to make a bridge between the Legacy 5 and Legacy 3. Obviously due to the naming you know this new introduction was always planned, but most likely refers to driver count. Utilizing a new preparatory in-house 8mm poly-membrane driver our new toy purportedly gains greater speed and bass texture than it’s older brothers the 5 and 3. To tell you the truth, when I heard the word better bass speed............I was all done.....sign me up! Dual (2) Bellsing-Thieaudio (bespoke) tweeters blended up against a single Knowles ED29689 for midrange. All tied together with a three way crossover and two switch tuning system.

All this ends up pretty amazing when you realize Linsoul created Thieaudio in 2019?

The Thieaudio Phantom planar magnetic headphones ($349)

Voyager Series IEMs Voyager 3 (3BA, $100-200), Voyager 9 (8BA+1DD, $500-$600) and Voyager 14 (14BA, $1000)

Legacy Series IEMs Legacy 3 (3 driver $119) Legacy 4 (4 driver $195) Legacy 5 (5 driver $249)

Signature Electrostatic Series IEMs

A) Monarch Electrostatic Tribrid In-Ear Monitor with 1 Dynamic Driver + 6 Balanced Armature Drivers + 2 Electrostatic Drivers priced at $729

B) Clairvoyance Electrostatic Tribrid In-Ear Monitor with 1 Dynamic Driver + 5 Balanced Armature Drivers + 2 Electrostatic Drivers $699

Thieaudios proprietary new Poly-Nano-Membrane Dynamic Driver

Enjoyable balanced tuning with value leading technicality
Middle-ground (comfort-zone) tuning and price
New and reworked treble experience
Ear-shape-data-base semi-custom fit
Dependable .78mm 2-pin OCC 4 core 3.5mm copper cable
Over-the-top, flagship-level carrying case
1 year warranty
2 switch (IEM mounted) tuning system for bass and mids
Hand-done paintwork joined with German medical grade resin construction
Individually frequency matched and channel balanced
Free shipping world-wide

Chicks dig em

In 2017 the word “Giant-Killer” was used by reviewers to describe a great value IEM. After a while the word reached a ridiculous level of use saturation.............losing its power with all these giant-killers walking around? In 2018-2019 a now illuminated reviewer (you all know who he is) used the single word “technicalities”. Just in-case you haven’t noticed........the buzz-word for 2020 is “tone”.

Yep, that’s right, tone actually wins out over “technicalities”. So while the Thieaudio Legacy 4 is not 100% perfect it IS a giant-killer. I’m bringing the term back just for this single review. The Legacy 4 is rumored the best in tone in comparison to the entire Thieaudio product offering. Keep in mind the L4 is the only singular Thieaudio product I've heard.

The L4 is the most tone balanced IEM I’ve ever heard. If the above is not enough for you then I don’t know what is? The Legacy 4 makes a great gift.......due to fitting everyone......due to the reserved hand done shell........and “ice-cream” tone. The L4 is the biggest gift of the year to the IEM community.


Model Title: Legacy 4 Universal IEM

Frequency range 20Hz-20KHz
Monitor Plug 3.5mm
Connector 0.78mm 2PIN
Sensitivity 108±0.5db
Impedance 9.4Ω
Noise isolation 26dB
Detachable cable

Equipment used:
Included 3.5mm cable, OCC Copper 4.4mm, SPC 4.4mm

Sony Walkman 1Z MrWalkman DMP-Z1 Emulation Firmware MK1 Region "J"
Sony Walkman 1A MrWalkman DMP-Z1 Emulation Firmware MK2 Region "J"
Sony TA Desktop DAC/Amp
Firmware Update 1.03
iPod Touch 5th Generaton 3.5mm output
Serial Number Legacy 4 provided IEM L4-0051
Switches set to stock setting (both down position 1,2)
After careful experimentation I stayed on stock switch settings.

Music used:
Singer Songwriter, Rock, Metal, Industrial, Rap, OST and EDM. Various quality from 320kbps to 24bit.

The Thieaudio Legacy 4 IEM was sent to me by Lillian at Linsoul for purposes of review. This is a single user experience, your end results may differ.

They have just 12/28/20 added CIEM as an option for $70 more.
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Very interresting read.
Is the L4 intimate sounding?
The soundstage is big? Not intimate? Though in hindsight it is slightly bright in the lower treble, yet for some it’s going to be perfect, for others possibly fatiguing............. after a while? Probably biggest thing is it’s missing slight physicality on some songs, in comparison to TOTL IEM? Still very much a favorite. This review was way back in 12/23/00.