FATFreq Scarlet Mini


100+ Head-Fier
How much bass would a basshead bass if a basshead could bass bass?
Pros: -Thundering bass
-Mids and Vocals still sound great considering the bass
-Extremely comfortable (with the right tips)
-Absolutely gorgeous presentation and IEMs
-Fairly detailed and natural sounding
-Did I mention Basssssss?
Cons: -This is -not- for everyone
-Bassy tuning takes away from the highs/treble the most
-A bit pricey for what would essentially be a niche/second or third IEM to round out a collection (unless you're a basshead and V-Moda headphones are your end game)
TL;DR: Bring on the wubwub.

Hi all. Dipping my toes into reviewing IEMs because this has been a fun hobby and being given the opportunity to demo a product, it only feels right to spend some time to give impressions as a way to appreciate the product and give back a bit.

At this point in time, if you've ever been interested in a basshead oriented IEM and are looking for the TOTL, FatFreq has probably caught your interest. If they haven't...


FatFreq is a company out of Singapore. Their popularity has seemed to increase very recently with some of their releases either from word of mouth to various reviewers and influencers. They have several line ups but their Maestro series is what has people most excited (maybe it's time to check out their Signature series?)


The Scarlet Mini is essentially a refresh of the Maestro Mini and was originally going to just be called the v2 (from my understanding and based on information found online... please correct me if I'm wrong and I'll be more than happy to edit this) before they decided to just name it the Scarlet Mini with a new look/color. I believe the Maestro Mini does have it's own dedicated v2/version update (with recessed 2-pin sockets, build-in mesh guard and slight tuning change for more natural bass timbre) but I digress.

Disclaimers: Shout out to @Sebastien Chiu - this product was received as part of the on-going Scarlet Mini Tour that he helped organize. I was given no instructions, not even told that I needed to do a review so these impressions are all of my own accord and desire to write about it.

Build Quality and Comfort
Photo dump time! The case and IEMs are absolutely gorgeous. They are some of the best looking IEMs I've seen and there are a LOT out there that look amazing. But, I'm sure I'll say the same thing to anything else that comes out.

They arrived in a padded hard case:






They came with their updated red cable and some tips/adapter. I didn't find the stock tips as comfortable for me (and I wasn't able to get the best seal with them) and, considering it looks like a size may not be on there, I only put them on for a moment before running my own tips.



I have a few sets of tips that I run that work for me. The nozzle on the Scarlet Mini isn't to the Zero Red levels but they're definitely not the smallest.
  • Dunu S&S (which are great for larger nozzles) did not seal properly in my right ear. I use the L size for the Dunu S&S which usually seal with larger nozzles. It felt like a channel imbalance when I tried these tips on the Scarlet Mini so I moved on.
  • SpinFit W1 (Size M) sealed properly but the right eartip got stuck in my ear when pulling out a few times. It felt a bit too tight of a seal.
  • Final Type E Clear/Reds - I feel like Goldilocks but this was the ticket/fit that I was looking for. I used the size L for these and fit is perfect and comfortable.
With the proper eartips, these disappear. They fit wonderfully, the smaller IEM is comfortable (like Kato sized but with bigger sound than the Kato) and I could easily wear these 24/7 without any issues (beyond my wife probably being mad at me for not hearing her).

But, how do they sound? Bass. Thanks for reading. We're out.

For the sake of not repeating/reposting other people's squigs (as I'm too casual for this to get my own measurement rig), I won't post it but you can easily find measurements which all tell you one single thing:


Would a subwoofer gif have worked better? Probably.

Gear Tested On: Primarily streamed music via either dedicated Streamer or Phone.

Phone chain: Pixel 8 Pro -> Abigail Dongle & Pixel 8 Pro - Qudelix-5k
Streamed Music chain: WiiM Mini -> JDS Labs Atom DAC+ -> JDS Labs OL Switcher -> Geshelli Labs Archel 3 Pro. (Oh god, if I had used the tone control on the bass to bump it up, I think my head would have caved in)

Lows/Bass: This damn thing hits hard. For such a smaller form factor of an IEM, the sound is heavy. At times, it felt like the bass was borderline -too- much and on some tracks, it felt like my head was nodding along to the music but not because of the music. But because of the incredible sub bass.

Yes, this is a -bass cannon™-. There is absolutely no apologetics to what the intent of this IEM is. The IEM will shake your head on tracks that have a lot of bass and will still make your head feel like it's thumping on tracks that don't focus on bass. But, I mean... that's what we're here for, right? You wouldn't have been interested in a Scarlet Mini if you weren't looking to rock out or wubwub out.

The best thing about the bass is that the focus is more on the sub bass and the rumble there vs mid-bass which reduces any potential bleed over to the mid-range (not that there isn't still some bleed but you'd expect more from looking at a graph).

Really, the quality, details, texture, everything about the bass feels like it could be the end game for a lot of bassheads. But this would not be an IEM that you'd want to have as your only set unless you were strictly just a basshead who only listens to EDM, hip hop or similar music. This is more of a second/fun set you keep which makes it a very niche pick up.

Mids: Considering how bassy this set is, how do the mid-range/vocals sound? Great, actually. They're pushed up/closer to you as a result of the overall sound package but far from recessed or clouded over. In fact, the vocals sound extremely natural and even female vocals still shine well on them, IMO. Still, this is not something you'd want to keep as a vocal centric set and/or your only set ever even with how good the mids (despite the heavy bass). There is some bleed over from the bass but it's not entirely taking over the mid-range.
Treble: IMO, this is the frequency that's the most effected by the bass. While the treble is definitely not fatiguing, there is definitely a bit of a lack of resolution/air/detail on the top end. That being said, It's hard to fault the Scarlet Mini for this deficiency as the top end sounds -good enough- considering what you're getting with the sound signature. In fact, while the advertising is that this is a V-shaped set, I would argue that it's a left handed check mark since V would indicate you're getting more treble/air and I don't feel that's the case.


These are not your reference quality IEMs and they don't make any attempt to advertise that they are though so I can't fault them on this.

Specific songs listened to and other Etc.:
Soundstage is OK. Imaging, separation is all not the strong points here. I don't think the technicalities are leading at their price point but I feel they're adequate enough that you wouldn't need to try and EQ it in this package. It's hard to make additional points because they're all just OK but you're not getting this set for those purposes which is why I think these are a great -fun- set but likely not going to be the only set you ever touch/get. I would argue that there's enough IEMs out there that provide that sound signature where you get from 'good' to 'great' on everything while the Scarlet Mini is about being a -bad@ss- set on the bass and being 'good enough' on everything else.

I won't breakdown how each song sounds like on the Scarlet Mini but hopefully this gives you an idea of the music I enjoy/listen to and gives you some color to what I felt the Scarlet Mini exceled at presenting to me.

Gorillaz - 19-2000 Soulchild Mix
Deadmau5 - There Might be Coffee
ACDC - Thunderstruck
Fleetwood Mac - Dreams
Ludwig Göransson - the Mandalorian Theme
Lumineers - Leader of the Landslide
Guns N Roses - Sweet Child o' Mine
Holly Cole Trio - I Can See Clearly Now
L`arc-en-Ciel - Ready Steady Go
Black Keys - 10 Lovers, Gold on the Ceiling

On a lot of tracks, the Scarlet Minis were giving me what I wanted from the tracks in terms of the overall sound package but gave me the bass that makes listening to music -fun- and engaging.

I would say that these (or likely the Maestro Mini though I haven't had a chance to listen to them yet) would be the next step up for something like the 7hz Legato in terms of a higher price point basshead set. I -love- my Legato and I think these extend better on details/mids/technalities over the Legato while hitting harder.

Other Things to be aware of:
From my understanding, there is a huge backorder right now on these. Also, I don't think I would pick up the red cable as they feel a bit pricey for it (as others have said). Again, be careful on your eartips and don't hesitate to roll them to find the best fit. I used the Abigail dongle which worked out OK but I did have to push the power on them a bit to get the most out of them. Qudelix-5k worked fine and they performed well on the Archel 3 Pro that I use. They're great for high volume listening and lower/mid volume because of the signature and there's no distortion on either side whether you want to drown the world out or use them for lower volume/casual listening.

In conclusion, bass.

The end.

But in all serious'ness, I think these are great for bassheads. While I -cannot- fault you if these end up being your endgame/only IEMs if you're a degenerate bass lover, that's likely not going to be for everyone. I think these would make a great 2nd/3rd option like having an all-star on your team who helps round out your line up when you need to drop the boom. Is the price worth it, though, for having it be a 2nd/3rd option? Price would be in the eye of the beholder and your choice.

Using my comparison of the Legato here... If the 7hz Legato were like the valedictorian of their Bassy Bass High class, the Scarlet Mini holds the doctorate and just published a Wubwub thesis that should be reviewed by anyone who wants to subscribe to that sound signature.

Thanks for reading!
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Slight updated note: One additional point too that I forgot to say on my review was that they scale so well on your equipment. I ran the Abigail dongle and Qudelix-5k for majority of my listening since I usually associate IEMs with more portable listening and have headphones dedicated to my headphone amp.

Abigail sounded great, Qudelix provided some additional oomph but the difference wasn't like mind blowing or too far off (felt like a 5% boost or something).

I only tested like one or two tracks just to see how they work on my Archel 3 Pro which is a fault of my own for not immediately picking up the difference. But, holy crap, I spent most of yesterday with the Scarlet Mini plugged into the Archel and the extra power and everything special about the Archel (the Sparks op amps and everything) really brought out the dynamics, the detail, the high end/treble a bit more. It has been addicting how good this combo works and definitely recommend playing with all your gear.
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Great review. Now go buy one!
Oh man, I am definitely tempted. I'm also curious if the Maestro Mini may by the ticket.


Headphoneus Supremus
Best Bass-head IEM Ever?
Pros: Vast bass to satisfy the most demanding bass-heads, bar none
Bass in most case will not bleed into the midrange
Really good extension on both ends
Non-fatiguing treble
Good midrange performance
Cons: Not the most resolving IEM
Tip and source dependent in some cases
May not be your all-rounder IEM
Best Basshead IEM?​

FATfrequency is a small boutique IEM company from Singapore that has gained quite a popularity during the last two years, mostly due to their secret weapon to make IEMs with huge bass without bleeding into the Mids.

I have the chance to demo Maestro SE and Maestro Mini from FatFreq for a week, and I demoed Grand Maestro during the SoCal CanJam from FatFreq’s booth, so I am familiar with their products.

Thanks for @Sebastien Chiu and FatFreq for organizing this tour so that I have this opportunity to demo the hard to find Scarlet Mini, many headfiers wait for weeks if not months for theirs to arrive after order.


Scarlet Mini is a BASS CANNON™, which is patent pending technology for its magic that having the highest bass shelf without ever bleeding into the midrange. Many technologies are used to create the Scarlet Mini; readers can refer to the official website below for details:


You can order directly from their website for $635, or $794 with upgraded silver red cable, which is the version I am reviewing with. US customers can also order from the well-loved Musicteck for the best service. However, due to the recent backlog, the waiting time will be long.

Now let me directly go to the sound impressions. Most of my listed YouTube music below were used from my laptop to Schiit Multibit Modi2 to Flux FA-10, or Tuba tube amplifier, some are directly from Cayin RU6 from laptop. I also used Sony NW-WM1AM2 and Hiby RS2 with Scarlet Mini to listen to lossless local files. I will talk about the sources in the end.


As expected, the bass of the Scarlet Mini is huge and powerful, but not bloated in most cases. Depending on your taste, the bass of Scarlet Mini is more on the sub-bass, and you will feel more rumbling than hard-hitting punches.

The quantity of the bass is more than enough for most of the people, potentially there are few who may want to have more mid-bass in proportion in terms of the overall bass performance.

The quality of the bass is pretty good, in terms of details and texture. However, I would say that because of the huge bass volume, Scarlet Mini is still not the best compared to TOTL IEMs in terms of the bass quality. However, it is expected given the huge price difference.


The midrange of Scarlet Mini is surprisingly good for a bass-head IEM. Vocal is pushed behind the instruments when bass is strong in the music as expected. The midrange is so good that Scarlet Mini is very close to being an all-rounder.


The treble of Scarlet Mini is well extended, not rolled off. It is also not offensive, non-fatiguing. Compared to the bass and midrange, the treble of Scarlet Mini is de-emphasized in some way and therefore you won’t find class-leading details.

Overall Sound Impression

Even though the performance of midrange and treble of Scarlet Mini are very decent, I eventually categorize Scarlet Mini as a specialist, instead of all-rounder. The best music genres for Scarlet Mini are Hip Hop, and electronic.

Technical Performance

The soundstage of the Scarlet Mini is good, but not the star of the show. As I mentioned above, the detail-retrieval is also not the TOTL level. However, both sound stage and detail-retrieval are very good in the price range.

Cable Rolling

I unfortunately don’t have the basic stock cable to compare, but for the upgraded red cable, I would suggest go for a better cable if you want to achieve the most potential of Scarlet Mini. I tried Effect Audio code 24 and most of my listening is done with the code 24 cable. It significantly improved the performance of the Scarlet Mini, I know this is a cable that is more expensive than Scarlet Mini but readers can check out the FatFreq thread, there are some much less expensive cable suggestions posted there.

Tip Rolling

Okay, I did not do too much in this department, but for most of the bass heavy IEMs, good sealing is essential. I find TRI Clarion tips a very good match for Scarlet Mini.

Music Examples

Jazz Variants La Bamba:

This is purely guilty pleasure for bass demonstration, especially the ending part.

Childish Gambino – This is America:

This classic Hip Hop is such a pleasure to listen to with Scarlet Mini.

Macklemore & Ryan Lewis – Downtown:

Another classic Hip Hop shoot in one of my favorite cities.

Big Boi – Kill Jill ft. Killer Mike, Jeezy:

This is a classic music to use for Bass test, especially for the proportion of sub-bass and mid-bass. Compared to another IEM: CFA Bonneville, you can hear the difference very clearly that Bonneville has a higher mid-bass emphasis while Scarlet Mini is more on the sub-bass side.

FKJ & Masego – Tadow:

This is very interesting simple music that Scarlet Mini performs also very well.

Norah Jones – Don’t Know Why:

Female vocal focused music but Scarlet Mini is doing not bad at all.

Final Thoughts

Scarlet Mini is not very picky in terms of sources, but sometimes sources do make a huge difference. For example, there are some music played from RU6 or RS2, both R2R based, that I found the bass too overwhelming on Scarlet Mini. However, when I shifted to my Sony 1AM2, the bloated bass was no longer there. As matter of fact, Sony NW-WM1AM2 is a very good match with Scarlet Mini, it can almost be used as an all-rounder IEM.



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500+ Head-Fier
Not Just a BASS Cannon
Pros: Great bass, it rumbles in ears and feels fantastic.
Comfortable small shell
Podcasts sound impressive.
Vocals are impressive.
Enjoyable for most music, and a fun experience.
I dig the case.
Cons: Resolution and imaging is off to me.
Seems to do better with more power
Detail can be lost, and tonal balance is a bit off.
On man tracks this is just blah, so it is a specialist not an overall best iem.
Red cable doesn’t feel worth the premium 140 bonus
Mids are more of an afterthought
On certain tracks this is world-class, but a specialist/toy not a daily driver.
“Not Just a Bass Cannon’”

### TECHNOLOGY So this does have a lot of technology, let’s show it here and then move on.


(Patent Pending) Using proprietary dynamic woofers, bass chambers and acoustic damping networks, FATfreq was able to design the deepest bass ever recorded of over 30dB, expertly controlled below 200Hz with zero mid-range bleed. A FATfreq innovation pioneered and perfected for sheer bass power.


FATfreq uses proprietary circuits to correct the non-linear impedances of multi-driver systems. The different output impedances across all your devices cause frequency response to vary. Having this tech ensures consistency in frequency response for all our IEMs when plugged into any device - Be it your mic-pack, mixer board, phone or dedicated DAP.


Inspired by the anatomy of the traditional french horn, FATfreq uses exponential horn curvature for gain control and to improve treble tonality via acoustics. Providing you with Smooth, natural sounding highs, grounded by a nice timbre in the mid and low frequencies.


The absence of a DSP in IEMs means that we have to match the phase of multi-way systems via Acoustic delay. Using proprietary structures, we were able to align the low, mid and high frequencies such that they reach your eardrum in a coherent manner. Giving you the sound accuracy and resolution demanded on stage and studio.

Bass (20-60 Sub Bass, 60-250 Hz Mid Bass)

Bass good, but how good. It’s strong and overpowering. I want bass quality and rumbling, not just volume. I think the quality is fine, but a bit too much for my personal take.

Midrange (250 HZ to 800 HZ Low Mids, 600-200 Hz Mids, 2000-5000Hz Upper Mids)

The timber and tone is great on this iem, the vocals are very nice and podcasts sound good on it. But there is a richness to voices that is off to me a bit. It’s nice, its fun, but it pushes somestuff out a little bit.

Treble (5000- 10000 Trebble/Highs, 10000 ++ HZ Upper Trebble & Air)

The treble is a good part of this set and this iem has good detail and technicalities but it doesn’t seem class-leading or perfect to my ears. I like it, but it feel tonally off a bit to me for what I want. It has a certain bass head type that it pushes towards and not a push for naturalness or a balanced signature. It does have a great tuning and is very impressive.

Shell -

The shell is pretty, it fits great and and it’s small. Often time high end shells are massive but part of the apeal of this set is how small it is. Very comfortable for me.

Case- The case isn’t something that I personally would use. But it’s a nice case and I enjoy it a great deal.

Cable- Not a huge fan of this cable. I would personally recommen getting the cheaper version with a cheaper cable and swapping it out. If you want a fancy cable, go for, but it’s not for me.

Tip Selection - I was pleasantly surprised with the tip selection! I really enjoyed them.



Sound - Final Impressions

While this iem is very good, and almost perfect is seems that there could be some room for some slight improvement here. I think the bass physical impact of the Monarch MK 3 is better, and I think the tuning could be slightly improved with EQ, but

Gifting/who is it for: I think this is a nice hifi iem to gift to someone, but it is rather expensive. I would recommend a cheaper product for most people. It is very nice, but the shells look a little blarg for an 800 dollar iem. The packaging is fine, but just that… fine. It’s a good iem for bassheads, but I don’t think it’d be a safe bet to give to someone.

Pairing: I used a Quidelix 5k for mobile, my dongle Dac iBasso DC04 for my laptop, and my JDS labs Element III MK2 Boosted for my Desktop PC. I also tried the iem briefly on the Apple dongle as well. This iem did feel better when it had more power in my ears. I’m not sure exactly why, as the vibration was more apparent when it was. I could be wrong, but it’s just my experience in my limited testing



This is a fantastic basshead iem that I fully enjoy. I do like it a great deal, and have enjoyed my time with it, but tonally prefere Fatfreq GM or their SE. (Those were just demos). I do like this iem a great deal, and could see myself owning in my collection if money were no issue. But I think personally I’d rather own something else, but this is an exceptional iem, and probably the best basehead Iem that I’ve ever tried. Very enjoyable, very fun, but it does need a ton of power, and some songs feel a tiny bit off as this is not my preferred sound signature

I would love to own a Basshead iem if price was no issue, maybe I would spend 300-400 for one, but I think I’m going to pass on buying a Scarlett mini on a personal level. I don’t need it in my collection, but It is tempting with its darn beautiful shell, forward vocals and a beautiful fun vibrating shell.


Headphoneus Supremus
FatFreq Mini Scarlet – Fat Bass and yet so controlled
Pros: Fattest controlled bass I know
Lots of bass and still very balanced
Energetic presentation suitable for more modern genres
Very comfortable
Nice mids and smooth highs
Cons: Needs more power then other IEMs
Not the last word in resolution
I was very excited about the Mini Scarlet from FatFreq, the specialist for IEMs from Singapore. The model promises nothing less than the deepest bass in the world in an IEM. This is to be made possible by the world's first 30dB sub-bass boost. But is it even possible to control such a sub-bass shelf? I want to get to the bottom of this in the following review. Not only is the bass range to be controlled in a very controlled manner below 200Hz, the other frequencies are not ignored either. FatFreq's specially developed tube-less hyper tweeter system ensures the necessary brilliance of the treble up to the 40Khz range. All the acoustics and technology fit into an amazingly small space, making the Mini Scarlet very ergonomic and lightweight.

For this review, I am using the version with an additional upgrade cable. This is a specially made SPC cable with interchangeable plugs in the sizes 2.5mm, 3.5mm and 4.4mm. It not only looks very high quality with the silver and red colors, but is also very soft and flexible. It matches the design of the Mini Scarlet perfectly. The Mini Scarlet without upgrade cable costs about 600€. With the upgrade cable it costs about 750€. I would like to see every manufacturer offer this type of connector for replacing the connection in the future. So far, very few have done this.


FatFreq became world-famous with the Maestro series and has developed several technologies in recent years that are now also used in the small Mini Scarlet model. The price/performance ratio of the Mini Scarlet is really very good. Here you can see that the expertise and technologies of recent years have also been adapted to the small model and for a very good price, in my opinion. I would now like to talk about some of the technologies.

The Bass Cannon technology, which makes it possible to drive a bass so high without it distorting. This is achieved by specially developed dynamic woofers, bass chambers and acoustic damping networks. With all these components, FatFreq has managed to boost the bass below 200Hz by 30dB without it spreading into the mids or getting out of control in any other way. Amazing!

FatFreq has developed its own circuits to correct the non-linear impedances of multi-driver systems. The different output impedances of the DAPs always result in the same frequency response. You no longer have these sometimes large differences in sound when you switch from a DAP with less than 1 Ohm (e.g. iBasso DX320) impedance to a DAP with 2 Ohm (e.g. Shanling M8) impedance. With some IEMs that change their frequency response, this is usually noticeable in the bass range (more/less).

With the Sonar La Trompa technique, which was inspired by the anatomy of the traditional French horn, FatFreq uses the exponential curvature of the horn to control the gain and improve the tonality of the treble. This makes the treble softer and more natural sounding.

Phasealign in FatFreq's IEMs ensures that when multiple drivers are used, the low, mid and high frequencies are aligned to reach the eardrum in such a way that the sound is perceived as if it all comes from a single driver.

So there is a lot of know-how available from FatFreq and many technologies that have been developed in recent years in the higher-priced products are used in the inexpensive Mini Scarlet. I couldn't find out from the product sheet itself how many drivers are used here. However, there will be at least two, a DD driver for the brilliant bass range and a Hyper Tweeter for the treble. There may also be a BA driver for the mids or the DD driver may also cover this range.

The scope of delivery includes a transport box in which all the accessories can be stored. This includes the cable, some silicone ear tips, the connection adapters and a kind of business card with the inscription "Welcome To The Family". The workmanship of the Mini Scarlet is really top notch for this price. These shimmering red faceplates could easily be used in higher-priced models. In terms of comfort, this is a very comfortable IEM to wear. In addition to the ergonomic design, the low weight also contributes to this.



For the test, I used the Scarlet Mini via 4.4mm on my iBasso DX320 MAX Ti. The first thing that is immediately noticeable is the power it requires. All my other IEMs are easily satisfied with gain level 1 of the DX320 MAX Ti. With the Mini Scarlet, I have to use level 2 to be able to play at high levels. However, I actually find this advantageous, as it gives me a much better control range than with other IEMs.

When I put the Mini Scarlet on for the first time, I was expecting a real bass cannon and was so surprised that it naturally has a lot of bass, but I didn't expect it to be so controlled and balanced. But first things first. Tonally, we are dealing with a rather bright IEM that sounds quite energetic. It's not quite a typical V Shape tuning. The low bass range goes down very, very far. In the mid-bass range, however, it is not quite as strong as in the very low registers. That would be too much of a good thing and would certainly blow up into the mids. The Mini Scarlet has the "fattest" bass I know of below 50Hz. In the mid-bass range, it is quantitatively one of the strongest IEMs, but there are some that have an even harder kick bass, such as the Fir Audio Xenon6. Due to the fact that the mid-bass range is not quite as pronounced as the low-bass range and due to the lowering of the lower mid-range, none of the bass expands into the other frequencies. The tuning and development of FatFreq go hand in hand here and rein in this bass monster, which has enough control at all times. The impact you get here with metal and EDM music is remarkable and will satisfy every, really every bass lover. The quality is also surprisingly good considering the price range, although of course it can't quite keep up with much more expensive IEMs such as a Raven or XE6 in terms of bass quality. can keep up.

The stage imaging is not very wide, it is more of a direct-playing IEM. Except for the vocals, which seem a little more distant due to the reduction in the lower mid-range, creating a pleasant sound. However, the Scarlet Mini is by no means a very smooth IEM, but rather belongs to the genre of more energetic IEMs where things also get down to business in terms of speed. So metal with the bass boost and the tingling mids is a lot of fun.

Is it annoying in the treble? Fortunately not, although its tuning doesn't artificially hide or smooth out details. But at no time did I find the treble annoying due to sibilants or liveliness. In terms of resolution, it doesn't really lack anything at first, but in a direct comparison with the top IEMs in this category, such as a Raven, it becomes clear that the smallest details are somewhat blurred. I'm curious to see how this is with the higher-priced models such as the Maestro SE or Grand Maestro.

The Scarlet Mini from FatFreq is certainly one of the first models to consider for bass lovers looking for an IEM up to 1000€. It is an IEM that is simply fun to play and also cuts a fine figure technically. Coupled with the very good workmanship and impeccable comfort, the Mini Scarlet gets my full recommendation!
Hey there! Where would you place it in terms of resolution? Maybe considering Studio 4, IE600, IE900, Xenns Mangird, Maestro Mini, Softears Volume, Letshuoer S12 and so on.
And do you think it´s good for someone who loves enormous subbass, but not too much midbass in contrast? I´m more of a shelf than a slope guy I think.
Thank you!
Yes SM is definitely for subbass lovers. Resolution wise it's a slightly under U4s. When you want it all on the highest level then GM is the way to go!
The Mini Scarlet without upgrade cable costs about 600€. With the upgrade cable it costs about 750€.

Hmm, you mean in the store?
When it comes to Europe with shipping and VAT; customs, it's near 40% more

Or is there a place in the EU you can buy them from, for 600€?



100+ Head-Fier
Red Hot Bass
Pros: Exceptionally powerful low-end performance
Treble is distinct, edgy and clearly defined
Small and comfy earpieces
Cons: Bass gets fatiguing over time
Mids are an afterthought
Detail is lost in the aggressive tuning
Staging is pedestrian



Many thanks to @Damz87 for arranging the Australian tour of these and special thanks to @reallynotareview for lending his personal unit for this review.

In a world of Harman tuned IEMs, there seems to be a prevailing idea of what constitutes a well-tuned IEM (at least below a certain price point). Adherence to targets with minor adjustments and a FR curve seems to be enough for a not-insignificant number of audiophiles to praise or malign an IEM. FatFreq is a Singaporean maker that is seemingly hellbent on subverting these targets to attempt to achieve a hugely bassy IEM, in a tuning approach that seems to be unprecedented in its apparent ridiculousness. This review concerns their latest release, the Scarlet Mini (Scarlet) which promises more of this bass power. I mean, just look at this thing:

One can imagine what this would sound like but with the benefit of @ really not a review’s personal unit, I would embark on an odyssey in bass. But would this odyssey leave me high and dry in the middle of the desert? Or lead me to a bass oasis?

The Factual Stuff​

The tour unit came in a strikingly red pelican-style hard case that FatFreq terms the “FATBOX” with some rather nice foam within to protect your new toy. Additionally, the FATBOX includes a silica capsule to draw any moisture away from your IEMs, a cleaning brush and a red coloured pure silver cable with various terminations.


The earpieces themselves are seemingly made of resin with a tastefully red faceplate that is quite handsome to look at. Within the earpieces is a bit of a mystery as the driver configuration is not readily apparent from the FatFreq website. However, they do note their “Bass Cannon” technology to achieve deep yet strong bass with “zero mid-range bleed” as well as their linear impedance to match any source, Sonar La Trompa to provide nice highs and Phasealign to improve coherency.

They are priced at around 799 SGD to 999 SGD depending on your cable combo (this is the 999 SGD cable combo). This is around 600 to 750 freedom dollars at the time of writing.


The Opinion Stuff​



TL;DR: The Scarlet is a bass-heavy IEM that delivers powerful, deep, and resonant bass with good clarity and depth, although it slightly compromises on detail and might not suit everyone's preferences.

Well let’s not beat around the bush. The Scarlet is an absolute bass cannon as advertised. The tremendous boost in the low-end creates a strong sense of low-end body and presence. It is not just powerful in terms of sheer volume, it also manages to provide such a boost with sufficient clarity and depth. The sub-bass extends deep and rumbles very nicely with authority. “How” by Ella Mai has a pervading bass-line throughout the entire song befitting its genre and the Scarlet reproduces it with deep and resonant bass that adds a palpable texture to the music.

Moving to the mid-bass, I chucked on “Second Life” by Slander that has a mid-bass focussed bass line throughout the song and to no one’s surprise, the Scarlet provides an extremely powerful reproduction of the song. The punchiness and strength of the bass boost in the Scarlet manages to provide a strong sense of excitement and physicality to a rather small IEM that belies belief.

In terms of quality and textures, the Scarlet is not best in class, but this is not a situation of quantity trumping quality. By virtue of the rather aggressive boost, the Scarlet does not render the full detail of certain basslines such as that on “THE PLAN” from the TENET soundtrack opting for a more full and perhaps rounded presentation of bass versus a reigned in but readily dissectible form of bass.

Overall, the bass on the Scarlet is indeed its strong suit, the significant boost applied here does not turn the Scarlet into a indiscernible mess but rather remains controlled, quite detailed (considering the boost) and hugely fun to listen to. The only detriment to this robust bass tuning is that the detail invariably suffers despite remaining rather good considering the context and that this hugely bassy signature would not exactly be everyone’s cup of tea. I found myself somewhat nauseous after extended listening sessions with the Scarlet.


TL;DR: The Scarlet's mid-range performance is moderate, with a tendency for recessed and somewhat veiled vocals and instruments due to its bass-focused tuning, yet it manages to maintain intelligibility and balance in various musical contexts.
Given the tremendous bass boost, I was very keen to see the effect on the mid-range, understanding that a rather robust mid-bass region tends to bleed into the mids and detract from its coherency at times. Listening to “Out of Time” by the Weeknd, a track that uses a rather lush and warm sample from a city-pop track from the 80s combined with the male vocals of the Weeknd. On overly warm IEMs, this song has a tendency to sound rather incoherent with male vocals being thrown into the abyss and injected with a distracting amount of note weight. The Scarlets managed the song very well, with the Weeknd, despite being somewhat recessed in the mix, still managing to come off as coherent, intelligible and with a somewhat natural timbre. However, the male vocalists still remain recessed in the mix as the tuning of the Scarlet is invariably bass focused.

Putting on a duet to see the shift from male to female vocalists, “Can’t Love you Anymore” by IU and OHHYUK contains the heady and airy voice of IU and the crooning of OHHYUK. The Scarlet manages the balance between these two voices rather well, seemingly providing both with ample focus as the song switches between the two. The bridge of the song also contains a call and response between the two singers and the Scarlet doesn’t seem to place precedence on either voice.

Moving to female vocalists, “Billie Bossa Nova” by Billie Eilish contains a rather intimately staged song that is rather sparsely produced and has a focus on Billie’s whispering singing voice. The Scarlet creates a rather excellent reproduction of the vocals but unlike other IEMs with a more “balanced” tuning, the Scarlet seems to place Billie’s vocals further back in the mix and detracts from the detail and emotion behind such vocals.

More acoustic and less bass heavy productions such as Laufey’s “Second Best” presents in a surprisingly good manner. Without the ever-present bass throughout, the mids are reproduced quite well, specifically the soulful voice of Laufey.

Instrumentalization in this region is a key selling point to me as I do enjoy a full and well detailed midrange. “Just the Two of Us” by Grover Washington and Bill Withers contains a wealth of instruments as well as the lovely voice of Bill and the Scarlet manages to do a decent job of rendering both. The saxophone, the keyboards and the steel drums are rendered quite well but as was the case outlined above, are thrown to the rear of the mix and inevitably lose a sense of detail and engagement.

Overall, the Scarlet is a bit of middling mid-range performer with the region recessed rather veiled and somewhat lose a sense of engagement. However, the Scarlet does well when considering the context of the FR curve as a whole as still remains intelligible, just not that engaging.


TL;DR: The Scarlet's treble is surprisingly refined and present despite its bass-heavy nature, offering a good rendition of higher frequencies with a slight edge in sibilance, lacking the splashiness of brighter IEMs but still maintaining a fun and articulate upper-end.
Moving on to the treble region, one would usually believe that an absolute bass cannon such as the Scarlet would likely have a terrible upper end. To that I would say that you are wrong. The treble on the Scarlet can provide a rather good rendition of percussive instruments such as those on “Reckoner” by Radiohead. The claps, hi-hats and maracas manage to present themselves rather forwardly in the mix and with a slight sense of sparkle and tinkling quality to them that belies the robust low-end.

The brush on the hi-hat throughout “The Demon Dance” by Julian Winding is a constant test for treble response as it is a busily produced track and poor treble tuning usually leads to it being lost completely. The Scarlet renders this hi-hat with a whispery quality that is soft, subtle yet articulate in its nature. Treble therefore does not have the same splashy and spine-tingling quality that it has on brighter IEMs but it is definitely not completely dead as one would usually believe on a “bass-head” IEM.

Higher register female vocals reside in the upper-mids and lower-treble and a more aggressively tuned IEM has the propensity to be sibilant at times. The Scarlet has such qualities with sss sound coming from f(x) in “4 Walls” (and perhaps female K-pop vocals as a whole) having an edginess to them that is ever-so-slightly grating on the eardrums. I would not term these as hugely sibilant but there is a slight sharpness and pronounced edge to notes in this register.

Overall, the treble of the Scarlet is not too aggressively tuned but done in a manner that retains the fun-factor of having a present and well defined upper-end. There is no goosebump inducing moments when a cymbal crashes but there is a subtle and refined approach to the treble that allows it remain present in an overwhelming wave of bass.


TL;DR: The Scarlet's soundstage is relatively confined with limited width and height, and while it offers good imaging and layering abilities within this space, its aggressive tuning leads to some loss of detail, especially in the mid-range.

Staging on the Scarlet is rather confined in the grand scheme of IEMs. There is no real sense of width nor height on the Scarlets with orchestral recordings such as “One-Winged Angel” by Nobuo Uematsu remaining rather pedestrian in terms of stage size. There is perhaps, an enhanced sense of depth in the staging owing to the robust bass and slightly elevated treble leading to a very forward low-end and everything else sort of sitting behind it “on the stage”.

The imaging abilities of the Scarlet are rather good in its ability to adequately position instruments and vocal lines on its rather confined stage, presenting a layered and articulate rendition of overlapping instruments and voices in busier productions such as “Fine” by Taeyeon.

In terms of sheer resolution there is a loss of micro and macro detail by virtue of its aggressive tuning. The recessed nature of the mids seems to present a more ‘muffled’ and ‘veiled’ rendition of music that makes it harder to discern detail in the mid-range and to a lesser extent in the treble regions. That is not to say that the Scarlet is slouch, it remains competent but detail is not exactly jumping at you by virtue of its tuning. Subtle details on songs such as “Rush Over Me (Acoustic Version)” by Haliene which are readily apparent on more neutrally tuned and resolving IEMs in the market remain rather indiscernible on the Scarlet unless listening carefully.


There is no mistaking what the Scarlet is all about and that is bass. Powerful in quantity and surprisingly articulate in its quality, the Scarlet is an IEM that could be characterised in a phrase of “in spite of”. In spite of such an overwhelmingly bass-focussed tuning, it remains still coherent, in spite of a ridiculous and sometimes nauseating bass tuning it retains rather good treble performance. The only issue with the Scarlet is that it appears to me to be a ‘gimmick’ IEM as I do not feel that this would be the ideal daily driver of any audiophile but it manages to be enticing in spite of this rather extreme tuning. Mids suffer slightly and if you’re a fan of acoustic folk songs of the 60s recorded in mono, the Scarlet is likely a miss.



vs FatFreq Maestro Mini​


The Maestro Mini (MM) is a predecessor of sorts with its spot in the product line being prior to and under the Scarlet. However, the footprint and price-tag remain fairly similar and as such it would be key to compare the two. Thank you to @tfaduh for providing his personal unit for the purposes of this comparison.

The MM presents a greater overall tonal balance when compared to the extremes that the Scarlet pushes. In terms of the low-end, the MM, whilst being no slouch in the grand scheme of things, has a lesser bass boost and perhaps is actually not as detailed or speedy as the Scarlet. The mid-range is the key advantage that the MM holds over the Scarlet as it’s presentation feels more in line with the rest of the FR curve. There is a slight thinness to notes in this region but it feels much more balanced overall. In treble, the Scarlet seems to be more sparkly and more dramatic in this region creating a more crystalline and precise rendition of treble whereas the MM feels more restrained and smoothed out comparatively speaking. IN terms of technical performance, the two are relatively similar in terms of micro and macro detail retrieval on a critical A-B listen. However, anecdotally, spending 2 weeks with the two as my daily drivers I found that the Scarlet feels comparatively more veiled and less detailed due to the more aggressive tuning approach. Stage-width is perceived to be greater on the MM but is not as deep as the Scarlet.

Ultimately, the Maestro Mini could potentially be a daily driver, the Toyota Corolla to the Scarlet’s weekend warrior Miata with a roll cage with an LS motor that has somehow has been shoehorned in and is ready to kill you at a moments notice. Pick your poison.


One thought coming to my mind here namely lessons learnt after multiple DAPs, DACs and Amps plus headphones and IEMs is synergy! Hoping for the one and only holy grail Setup is maybe just a nice wish unless buying according synergy transducers and I don't believe even the best sources are an exception here. There's a reason why people are having multiple devices in parallel or reducing inventory and keeping only the ones with right synergy.

Chord Mojo 2​

I would term the Mojo 2 as a slightly warm but very technical source. The combination of the Scarlet and the Mojo 2 yielded a rather good result, providing a powerful yet controlled low-end, a competent mid-range and some rather crisp treble.

The bass on this combination provided the full-bodied and robust boost offered by the Scarlet but in a controlled and detailed manner, not smearing into a mess like the M6U.

The vocals, whilst slightly recessed in the mix, remained still fairly present enough to enjoy and both female and male vocalists retained a level of emotional engagement.

The treble, whilst not as sparkly nor spine-tingling as the M6U below, created a manageable and non-fatiguing rendition that was still quite crisp in its rendition.

Technicality-wise, the Mojo does not disappoint by drawing out some microdetails in what is a rather coloured tuning. The crossfeed function of the Mojo 2 did help to improve the perception of stage width but considering the already-congested feeling of staging on the Scarlet, it was hardly a revelation.

Overall, I feel that this was the best syngergistic combination for the Scarlet in my small collection of sources.

Shanling M6 Ultra (M6U)​


I would term the M6U was a warmer source that seeks to enhance note weight.

The M6U and the Scarlet is an indulgent pairing that essentially boosts a low-end tuning that doesn’t really need any boosting. The combo with more bassier productions rounds out and smooths out the low-end far too greatly. Bass notes become too smeared and lacks the incisiveness seen on other source chains to the point of creating a more indiscernible sound signature.

Utilising the two with more acoustic music such as “Take Me Home, Country Roads” covered by Lana Del Rey being rather veiled and bloaty at times, imbuing a note weight that is highly unnecessary for the sparse production and focus on female vocals. Vocalists, both male and female are fairly recessed in the mix in this combo, overpowered by bass and treble.

Treble is very sparkly and some female vocalists do tend to get a little sibilant as was the case with Ariana Grande’s “34+35”.

Overall, my time with the M6U and the Scarlet was limited and that speaks to the poor synergy between the two.

Luxury & Precision W4​

The W4 is a rather crisp and fast source, providing a somewhat w-shaped sound. The combination of the W4 and the Scarlet was a bit of a mixed bag. The heightened upper mids and treble seemed to draw out some sibilance from female vocalists but also added a layer of crispness and sparkle that was excellent with certain tracks. The mids were brought more forward into the mix and the overall tonal balance became much more in line with other competitors in the market.

However, the aforementioned Bass Cannon was reduced to a bloaty and boomy mess with the W4 with the bass performance being degraded quite heavily. The results of this pairing were very glaring to the ear and whilst some elements were quite good, the bass was basically unforgiveable in my books. This was alleviated somewhat with some fiddling with digital filters but the overall performance in the low-end left a lot to be desired.

Overall, this is not a pairing that I would recommend.

Value & Quality of Life​

Priced between 799 and 999 SGD, the Scarlet inhabits the rather competitive sub-kilobuck market that is crowded with plenty of IEMs. Where the Scarlet seems to separate itself from the pack is its extreme tuning that emphasises low-end. And whilst it does detract from other elements of sound (as outlined above) it presents a wholly unique offering in the market (FatFreq compatriots excluded) that is able to satisfy a rather niche group of audio-enjoyers and appeal to a larger crowd looking to fulfil specialist slots in their collections.

The included accessories are rather excellent with the FATBOX providing a rather robust albeit large means of transportation and protection. The silver upgrade cable is rather striking to look at in its red hue but remains lightweight, ergonomic and rather pliable. The colour and the lightness and thinness of the wire used does present some other thoughts of cheap and chintzy but ultimately I cannot detract any other points from the cable.

The earpieces themselves are rather small and lightweight. When compared to the absolute huge earpieces and huge nozzles occupying the market, the Scarlet is a great breath of fresh air with its smaller and ergonomically shaped footprint. I found that the Scarlet felt at home in the ears for long listening sessions and I would not be too hesitant to say that this will likely work with a lot of ears in the world.

It would be remiss of me not to mention the rather public concerns of FatFreq build quality in recent weeks and months with mention in certain cricles of audiophilia relating to their poor customer service, slow turnaround times and a high instance of QC issues on their range of IEMs. This is something that has not presented on the Scarlets in my time with them but ultimately is a consideration I feel is worth pointing out.

Overall, I feel that the Scarlet, by virtue of its extreme tuning, has carved itself out of the pack and into a neat little niche. There is nothing boring about the Scarlet and that alone is perhaps worth the price of admission. I would not buy it to be my only IEM nor my daily driver (unless you were an absolute bass-head) but I feel what it brings to the table is wholly unique and that is definitely a great boon to its value proposition in the market.


It is a common theme for marketing to overpromise and then underdeliver. In the case of FatFreq and the Scarlet, bass cannon did not underdeliver. The Scarlet provides a unique but potentially polarising sound signature that has more bass than most know what to do with, a middling lower-midrange, a slightly spicy upper-mid range and a rather competent and subtle treble region. These elements combine to create a rather mixed bag of sound but what it does well in, it does unlike any other IEM in the market. To me, this is a specialist through and through and whether that is worth the price, is really up to how much you love bass or perhaps, whether you have been looking for the fun weekender IEM to complement your daily driver workhorse IEM.

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Hey there! Will they fit smaller ears? IEMs that are fine for me are the Letshuoer S12, Galileo, the Sennheiser IE lineup, the 7hz Sonus and the Truthear Hola.
I´ve had problem with Mangird Tea, Studio 4, SA6, Oracle, Hexa, Truthear Zero etc.

And would you rather recommend the maestro or the scarlet mini for someone who prefers a bass shelf (subbass) to a bass slope (more midbass than the shelf)?

Thank you very much in advance! Great review :)

Bret Halford

500+ Head-Fier
The Cardinal of Bass
Pros: Bass. Bass. Bass. These aren't a cannon, they're as a ballistic bass warhead!
Subdued upper mids / lower treble minimizes technical requirements for the drivers
Cons: Overly expressed upper treble from the hypertweeter not great for some recordings / taste.
FATfreq Scarlet Mini

I have had some ear time with the new FATfreq Scarlet Mini now and my ears are starting to wrap around just how much bass this thing is injecting skullside. At least, when they are not cowering in fear.

This review will take the form of some brief initial impressions of the IEM and accessories, and then two parts of comparisons. First off, we'll compare the new Scarlet Mini to its blue bro, the Maestro Mini and then to its tribrid siblings the Maestro SE and Grand Maestro. There's also a bonus basshead comparison at the end, so be sure to scroll all the way through :)


In the world of IEMs and headphones, there are "all rounder" tunings and "specialist" tunings. The Scarlet is undeniably a specialist, a specialist's specialist even... a Basshead's bassy IEM. This thing is the Cardinal of Bass:


Who you calling mini?

I have mainly been listening to electronic music with them for which they are such a treat. The sub bass is as advertised even more crazy than the blue line, but the overall tuning and the detail brought from the new hypertweeter really keep things energized. The balancing act the team at FATfreq have pulled off here is incredible. Delivering this much payload while maintaining coherence - let alone a nice amount of detail - a true challenge.

This is not to say it will be an IEM for everyone or all music of course. The bass is front and center, and care of a slightly more forward tuning is more frequently present than in the Maestro. While I think you could get away calling most Maestros Neutral with epic sub bass, the extra mid bass here definitely pushes these into a more pronounced v shape tuning. But when they work, for ears that are ready... these are special in a way I haven't felt since the OG mini :)

Packaging and Accessories

Before we dive into the two rounds of comparisons, let's briefly comment on the quite nice accessories that came with Scarlet:


The sheer redness of the thing lol...

The first batch of Scarlets come with in a clever matching scarlet red pelican style case (FATfreq's own "FATbox"). For the first 300 units the red silver upgrade cable is available for free and afterwards looks like it will be ~$100.


The Hypertweeter deserves silver cable!

In each case (har har) the cosmetic pairing is delightful. While nothing world shaking, the silver cable with modular termination is a very nice inclusion and a big upgrade from what they included with their IEMs last year.

On with the show!

Red vs. Blue: Scarlet and the Maestros


I have been busy hard at work comparing the Scarlet to my horde collection of Maestros. Very arduous and laborious work I assure you :) But for my fellow head-fiers, I will go that extra mile! In particular: the Maestro Mini, the Maestro SE and the Grand Maestro.


Meet the Maestros, bottom to top: Maestro Mini, Scarlet Mini, Maestro SE, Grand Maestro (CIEM)

Mini vs. Mini

Starting off the comparison series, we’ll cut to the chase and compare the Scarlet Mini (for the purpose of this review “Red”) to its blue bro, the OG Maestro Mini (“Blue”). Given this is the primary comparison of interest, I’m going to devote a whole section on this one and then combine the Maestro SE and Grand Maestro comparisons in part 2.


The Blue Maestro Mini were my introduction not only to the Maestros but to FATfreq as a whole. I was so impressed with them I blind bought a Grand Maestro within weeks and from there the sickness progressed 🙂


My Blue unit is one of the earlier run, without any meshguard (talk about tubeless lol!) so particularly on the build, there have been improvements made that aren’t exclusive to the Scarlet seen here, but are interesting to note. FATfreq have constantly been refining and improving their products based on the surge of customer interest and feedback, it’s quite impressive to see!

The Scarlet features the updated recessed 2 pin connector, now standard across FATfreq’s Maestro series as well. You can see on the Maestro some of the connector imperfections present in their earlier runs, it is much tidier on the new recessed mount.


Also, note the improvements on the Scarlet nozzle profile. They’ve added a waist and taper to help it hold on to tips a bit better, something I appreciate a lot as the Mini’s are a bit prone to let them slide off.

Physically, the shape of the Scarlet is a bit more conformal, which made it surprising that, when I took these pictures, it was actually a bit larger than the OG:



Note the exposed balanced armature on my Blue, these things really get the drivers into your ear!

I would be surprised if either Red or Blue caused substantial fit challenge. Both are relatively small by modern IEM standards and give lots of options to pivot in ear for the ideal placement.

The OG Blue mini contains 1 DD for Bass and 2 BA for mids and Treble… rather than depend on large drivers or higher counts, the minis put these in an exceptionally small form factor to get those drivers as close as possible to your eardrum. Seriously, look at that BA right in the nozzle in the above pic (covered by a mesh on newer Maestro Mini models, but impressive to see), that is bringing the sound right to your front door!

We can only speculate as to the configuration of the Scarlet - beyond at least that it is a multi driver, hybrid and not a tribrid. At least one of the BA’s is a new “Hypertweeter” that produces sound up to ultrasonics comparable to EST drivers to spec, something I’ll touch on in the sound off shortly.

In terms of sensitivity, I found them very similar in terms of power/SPL needs, both requiring substantially less than their Tribrid big bros.

Sound Off


First things first. Yes the Scarlet has more bass than the Maestro Mini. Sub bass? Yes. Mid Bass? Yes. Bass Bass? YES.

It’s not a subtle difference either, it’s quite evident right away. Particularly the more forward boost protrudes higher up in frequency on Scarlet, so the Red’s Bass Cannon not only fires harder, it fires more often too. Whereas there are songs or even whole genres where you could listen to the Mini and not trigger the bass shelf at all, the boost is absolutely unavoidable on the Scarlet.

The tradeoff down low then depends on what aspect of FATfreq’s bass is most attractive to you. If you want the MOST bass, all day e’ry day, Scarlet is it. If you want a stealth basshead tuning that functions as a reference at fancy parties but somehow brings the woofer for Latenight, then the Maestro is the magic trick for you.

The upper mid and treble tuning differs quite radically. The lower/mid treble is much less pronounced on the Scarlet, this helps add to the sense of bass dominance, but it also masks some of the timbral shortcomings that are evident on the Blue mini which has relatively prominent ear gain. Whereas the upper mids / lower treble on the Scarlet is subdued, it’s a touch off kilter on the Maestro Mini, which adds a slightly cooler tonality to the otherwise textbook neutral mids/treble. Not necessarily unpleasant in either case, but a varying concession depending on your taste.

As advertised the hyper tweeter in the Scarlet does extend up to at least the 10s of kHz… it exposes some nasty edges in certain mixes or more frequently highlights recording noise. I’ll get into more detail (har har, pun fully intended!) on this topic when I compare the Scarlett to the EST loaded Tribrid MSE/GM, but in brief I find the combination of hyper detailed upper treble with subdued upper mids / lower treble on the Scarlet a bit unnatural. In most recordings it’s not an issue, but when it is noticeable I wouldn’t say to my ear it is an improvement over the more orthodox roll off in the Blue mini.

Any Color You Like


It should be clear that I take the view that the Scarlet is a specialist side grade compared to its more generalist forebear, the Maestro Mini. That is not to belittle the Scarlet or what it achieves within the realm it competes in. While imitators are trying to catch up to last year’s models… FATfreq have kicked up the Bass to a whole new level, topping even themselves.

There is a new Bass king in town, but the Maestro Mini’s Reference + Mega Bass is still unique. It seems like FATfreq don’t view Scarlet as a replacement either, thankfully keeping both available in their stable of offerings.

Regardless of your choice between minis, I think you will be happy. Be warned though, these mini bass cannons are highly addictive 🙂

Mini vs. Tribrids

Next, let's compare the Scarlet Mini to the two top end FATfreq Tribrid IEMs: the Maestro SE (MSE) and Grand Maestro (GM).


(left to right: FATfreq Maestro Mini, Scarlet Mini, Maestro SE, Grand Maestro CIEM)

Unfair? Absolutely, but everybody loves a good "David vs. Goliath" story, and - more importantly - it's good to understand how the addition of Scarlet affects the value prospect of the higher end models from FATfreq. Furthermore, the Scarlet features a new “Hypertweeter” balanced armature driver that is pegged to compete with electret (EST) drivers in the high frequencies which is interesting to qualify through listening.


My GM and MSE are pushing a year old now at the time of this review. My GM in particular is something of a prototype, they had not yet finalized the standard artwork for instance (so rather than FATfreq on the R piece, it should have the 16th note Semiquaver). In any case, newer MSEs and GMs have similar recessed 2 pin port to the Scarlet as was discussed previously. Instead, we’ll focus on the substantial fit differences and how this affects the product strategy.


And the “mini” name starts to make more sense…

The MSE and GM are both 12 driver Tribrids, featuring configurations of 1 Dynamic Driver for bass, 7 Balanced Armature for mids and 4 Electret EST drivers for highs. As you can see, compared to the 3 driver hybrid configuration in the pair of Minis, this takes a TON of space to fit. The body size on the MSE and GM are substantially larger, and I have found the Uni MSE to be a relatively hard IEM to fit.



MSE (left) and Scarlet (right)

This is a nice illustration of the fundamental trade off at play in driver configuration. A smaller footprint allows for housing that is compact enough to get the drivers themselves deeply inserted into the ear, whereas the Tribrids need an acoustic feed (tubes etc) to route the sound into your canal. The “bang for your buck” per driver is dominated by proximity to the ear drum, so the Mini’s 3 drivers hit far harder than the corresponding trio would back in the larger housing. We’ll talk more about the sonic implications in the Sound Off up next.

Of course, a time tested strategy for dealing with larger driver configurations and the ensuing volume is to opt for a Custom IEM (CIEM) shell. FATfreq began as a custom shop, and retain a strong tradition of CIEM design and manufacturing.


Scarlet Mini (left) and Grand Maestro CIEM (right)

This removes the fit variable, and makes for the ideal comparison vs. the deeply inserted drivers of the mini.

Sensitivity wise, both Tribrids require SUBSTANTIALLY more power than the Minis (like 10+ dB, basically a higher gain mode). I quite like hard to drive IEMs as it gives lots of flexibility for amplification. Fortunately the Minis are not exceptionally sensitive and are not prone to over saturation (background hissing) on any of my amps or DAP.

Sound Off


The MSE exemplifies the Maestro ultra tucked sub bass shelf plus reference tuning, that FATfreq have become famous for. In its upper mids and lower treble, it features a relatively textbook diffused field tuning, sounding a bit boring and reference like - until there’s content sub 150 Hz. Unlike the Maestro Mini, there’s no niggling minor timbral offset and it produces a clean, even slightly lean overall profile.

This starkly contrasts the mids/lower treble on the Scarlet that as previously mentioned are subdued to minimize the tuning impact and maximize apparent bass.

In combination with the much higher upper bass of the Scarlet, this means that the MSE sounds very cool and lean in comparison. Folks that found MSE slightly boring would do well to give the brand another chance with Scarlet.

Sub bass can get tricky to qualify at these high amplitude levels. But the Scarlet has notably more sub impact and presence than the MSE, which used to be my sub bass high water mark. It’s not something that requires focus or extensive comparison to qualify like the GM vs. MSE either… it’s quite immediately evident that Scarlet is the new Bass king.


Up high, true to their marketing FATfreq’s new Hypertweeter is definitely passing on detail and air comparably to the EST’s in the MSE. Unfortunately, because of the noted subdued mids, the extra treble energy seems a bit off for me on the Scarlet… with the ear gain profile of the MSE it makes sense and is part of a pleasant complete spectrum, but with Scarlet it kind of pops out of nowhere.

I can appreciate the challenge FATfreq faced here, bringing out details like this while sharing the stage with elephantine levels of bass is no easy task I’d imagine. Still, there’s no denying that the MSE’s EST drivers sound natural and impressive whereas the Hypertweeter although capable feels a bit gimmicky in the context of the Scarlet’s tuning.


The GM takes the tribrid configuration present in the MSE and adds a pressure equalization and tuning module that FATfreq call NOAH, as well as a tuning switch that allows you to deactivate the bass shelf in what they call "vocal boost" mode. To simplify comparison, I will be referencing the GM’s black, non vocal mode, which is the most similar to the MSE and Scarlet. The flexibility with the Blue (and tbd) NOAH modules and switch is a huge value prospect for the GM, but is outside the scope of this discussion.

Here, however, is where things got truly unfair… the equalized pressure is absolutely transformative in the quality of bass produced. I’ll just directly quote my notes here: “Unfair. Bass is less voluminous but eminently more textured. With equalized pressure, a transient process is revealed. Detail has delineation and edginess without sharpness.”

After A/B between GM and Scarlet, I absentmindedly kept the GM in ear afterwards and just kept listening for the entire album. Such a wonderful IEM.

Particularly with the SPL produced for the level of Subbass present in MSE and even more so Scarlet, having pressure equalization like on the GM with Black filter removes fatigue and allows our ears to extract more detail than I thought was possible at <50 Hz.

WIth the semi open cleanliness generally, the ESTs in the GM also particularly shine. They are more emphasized than on the MSE but with the open clarity I generally don’t find it objectionable. It lets them get away pushing a lot more detail than I would generally like in traditional unvented designs.

End of Line?


It’s truly impressive what the team at FATfreq have pulled off with Scarlet. It has a focus of purpose that allows it to achieve new heights in bass, not just for IEMs but for home audio period. This directivity comes at the cost of flexibility… certainly more so than their existing Maestro peers.

Compared to FATfreq’s existing TOTL models, the Scarlet doesn’t disrupt things too much, rather provides a welcome capable specialist to the selection. While the absolute sub bass king title of the MSE is now Red’s to own, the MSE’s textbook overall execution is still outstanding and well worth the cost of entry (both dollar and fit)! The GM’s equalized pressure venting is surprisingly effective for bass oriented tunings. The extra comfort and detail it brings make the concession to the bass level on the Scarlet remain palatable.


The right driver in the wrong place can make all the difference in the world...

The entire experience has left me dreaming of a vented “Scarlet turbo”, that combines the proximal driver benefits of the mini with the incredible textural delivery of the GM's venting. The open clarity might also shed a more flattering light on the hyper tweeter too in the process. Even as one reaches new summits of experience in this hobby, it is a good thing to keep dreaming :)

Bonus Round: Bass for the Ages

Does the Scarlet bass transcend topology?


In my spare time, when not greedily stuffing my ears with as many IEMs as possible, I maintain a collection of Fostex Biodyna TOTL headphones (TH900m2 Red, TH900m2 Pearl White, TH909, TrX Ebony). These models are Fostex’ own premium take on the evergreen Biodyna OEM models (EMu, Denon D2000/5000/7000 etc). In addition to the biocellulose driver’s exceptional low distortion (same tech that was in the legendary Sony MDR-R10), they are also notorious for their strong bass performance. The TH900 Red in particular remains a Bass head’s staple for over ear.

I was curious how the Reds would compare head to head, for Science 🙂

To cut to the chase, yes the Scarlet has more bass than the TH900. It’s not close. But it’s also not as far off as one would think looking at the frequency responses. But if you convinced a “normie” in your life to try both, they wouldn’t hesitate to tell you the Scarlet has more bass, even if they struggled to tell you exactly why.

The sensation of bass with IEMs is fundamentally different to on-ear. The haptics of over ear produces a lot of intrinsic bone conduction. This occurrs from the headphone’s mechanical surface touching your skin (pads and clamp), while also being coupled to the driver. You can think of this as a huge version of FIR’s Kinetic Bass, that envelopes your whole ear. The concept of “slam” makes more sense in this context. The driver and haptic response are literally barraging the side of your head with Bass energy.

For IEMs, like Scarlet, the internal nature of the source is very evident. It feels like there is a sub-woofer in my ear canal and the bass energy is trying to explode outward. There’s much less area for natural BCD around the canal. Factor in the higher acoustic impedance IEMs face in low frequencies, and a picture where you need to add 5-10 dB of bass boost to an IEM for the same apparent bass level starts to make sense.

So no, I’m not listing my Fostex in the classifieds any time soon, but YES the Scarlet Mini produces bass at a much higher level - even notable beyond the dramatic perceptual differences discussed.
I paid for the order on November 15 and was reassured by the email message it would be sent out in November or December.
For now (January 2nd) there is no info about my order.
Has anybody who ordered them in November received any updates about the order?
Thanks for the comparison with the TH900 - your comparison with Fir's kinetic bass confirmed my suspicion... that a TH900 is needed in a bass-head collection! 🤣
@alex5908, I also ordered in November and have seen nothing so far. In my last contact with them they thought they'd be sending out November orders by the middle of March.