Disclaimer: the kind folks of ADV.SOUND/ADVANCE provided me a copy of the M4 in exchange for my honest opinion, expressed through a detailed review, provided a copy of the M4. I am in no way affiliated with the company. Photos from: https://www.adv-sound.com/collections/all-collection/products/m4
 
About me:

I am a young music-lover and former music producer from a little place called Bergen, Norway. My belief is that good sound should be accessible for everyone and anyone, which is why this review is not written from an audiophile perspective. As for my sound preferences, I tend to go back and forth between a v-shaped sound and a somewhat bassy one, with a slight roll-off in the highs, depending on source material. Warm, lively, exciting, powerful and impactful are all appropriate buzzwords. Also, to make my reviews more accessible, I use nothing but a cell phone and a desktop audio interface while testing. But enough about me, let us get to it…

 
 
Packaging and accessories:
 
Rather standard stuff here, but then it is not something I give great importance. It Is miles ahead of the packaging you get with your average $10 earbud, but again, nothing special in this department. The accessories, however, were a pleasant surprise. You get a small and compact carrying case, similar to the one accompanying the Philips Fidelio S2. There is plenty of space to store spare ear tips and other small accessories, which is always nice. While we’re on the subject of ear tips, you should be more than covered there as well, as you get a total of 9 pairs included, 10 if you include the ones “pre-installed”. They come in the flavors of Comply foam, dual flange and silicon. I found the best fit to be amongst the dual flange ones.
 

Carrying case and the included ear tips.
 
 
Design, build quality and cable:
 
Design-wise, the M4 is in many ways a very interesting earphone. It features a very streamlined design, and thus qualifies as a “skinny” headphone. This makes it easier to insert it deep in your ear canals, for those interested in that. The design of the earphone itself is not the most flashy nor forward-thinking, but it does get the job done, seemingly focusing more on practicality than stylistic appeal .However, it is by no means an ugly product, just not something out of the ordinary. It is built out of premium materials, with some kind of metal used. I am not sure exactly which material is being used here, but it definitely has a premium feel to it. It is also very light-weight, which more often than not is a pro. Then there is the cable, which throws everything I mentioned earlier about a conservative design out of the water. This is something special. It is a braided cable made out of solid plastic, and it feels very durable. It is also, like ADV.SOUND proudly proclaim, essentially tangle-proof, which I can confirm. This is something I would like to see more frequently done by other manufacturers, and is one of the strongest points of this product.
 

 
An exceptionally durable cable.
 
Comfort and fit:
 
Here I must admit I struggled quite a bit. Coming from my newly obtained V-Moda Zn, a much more expensive pair of IEMs, I could not seem to get these to fit properly. I kept getting that “suction-cup” feeling in my ear canals, which was both uncomfortable and provided a lackluster sound. This was the case with the majority of the ear tips included. The comply foam ones and one of the dual flange ones were the only ones who worked for me and provided a decent fit. If/when you get a good fit, they are very comfortable. Little stress on the ears, especially due to them being lightweight. Just about as comfortable as most IEMs. Nothing horrible, nothing extraordinary, like Klipsch’s ear tips. You get the idea. Still, I had a much trickier time to get these to fit than the other IEMs I own, have owned or tried out, which made the experience reviewing these much less enjoyable than it could have been.
 

The earphones in all their glory.
 
Sound:
 
In this department, I mostly agree with what has already been said. First off, they are a rather balanced pair, in contrast to the vast majority of lower-end earphones, which either feature ear wrecking amounts of bass or none at all. No part of the sound is especially accentuated in a way that makes me notice it right away, which in my book is enough to be called “balanced”. Then a bit about the various sonic areas:
 
Lows: relatively solid. They do not dominate the entire picture, which of course is a good thing. From my experience they mostly delivered in the mid-bass and upper bass, with the sub bass levels depending strongly on fit. But there is potential for some serious sub bass rumble as well, as some forum users have already mentioned. Still, they are solid overall and more than approved.
Mids: nothing special here. Detailed enough, would not call them warm nor cold, from my own listening experience. These earphones are not mid-heavy by any means, but nor are they recessed. Again, very balanced. Nothing of note to complain about. Probably my favorite part of the M4s overall sound.
 
Highs: now these are not as good. They are a bit harsh and shrill. Fairly detailed, yes, but also unpleasant to listen, especially over time. I got a good amount of listening fatigue due to this. If you are not treble-sensitive at all, this may not be a deal breaker, but for me they were. The music I listen to is already packed with treble, so noticeable harshness can be borderline painful, as I am somewhat treble sensitive. Good detailing, but I wish they made them smoother, especially concerning long-term listening session. Not approved.
 
Soundstage: not bad, not extraordinary. It is fairly good, without being mind-blowingly good and jaw-dropping. About as good as you can get for the price. Not bad at all.
 
Tonal balance and dynamics: I did not notice anything weird or off-putting here, which I guess translates to “good performance” in both of these areas. Nothing of note.
 
Overall sound: good detail for the price. If not for the harshness in the highs, these would be sonically excellent given the $40 price tag. The lows, mids and highs are all filled with plenty of detail, which should satisfy most people looking for a cheap and durable pair of IEMs to use on the move. Sounding about as good as you get for $40 definitely makes these a pair to consider.
 
 
Verdict: 3,5/5

Disclaimer: The kind folks over at RHA provided me a sample of this unit. This, however, will not impact the opinions or the verdict in any way. Shots from the official RHA website.
 
 
About me:

I am a young music-lover and former music producer from a little place called Bergen, Norway. My belief is that good sound should be accessible for everyone and anyone, which is why this review is not written from an audiophile perspective. As for my sound preferences, I tend to go back and forth between a v-shaped sound and a somewhat bassy one, with a slight roll-off in the highs, depending on source material. Warm, lively, exciting, powerful and impactful are all appropriate buzzwords. Also, to make my reviews more accessible, I use nothing but a cell phone and a desktop audio interface while testing. But enough about me, let us get to it…
 
 
Design and build quality:

If there is one aspect where all other headphone manufacturers need to follow RHA, this is it. These guys are built in stainless steel, which leads them to perform WAY above their price range is terms of quality and build. The cable is also fortified with steel in two places: around the 3,5mm plug, where it connects to the sound source, as well as where the cable splits into two. More on the cable, it feels durable enough for regular use, especially with the mentioned fortifying. However, it does get a bit tangly, which is a bit annoying to deal with. Design-wise, it is also an excellent performer in my book, as I really enjoy their classy, subtle and luxurious looks. This is an aspect many, sadly enough, tend to at least partially ignore. I can therefore happily state that this is not the case here.

Here you can see the design of the MA750i's, where the build quality clearly shines through.
 
 
Comfort:

Due to their stainless steel build, they are slightly heavier than most. However, with their over-ear supports, which may not be to everyone’s liking, they stay secure and fit well while not heavy at all. As for comfort, they come with a whopping 10 pairs of included ear tips, two of which are double flanged, with another two made from memory foam. After finding the best fit, which should be pretty much impossible not to given the huge amount of included ear tips and varieties, they stay comfortably in my ear, and I can wear them for hours without any major discomfort issues. You might need to go through a few pairs of ear tips in order to find the one that suits you the best, but once you manage that, there is no need to look back.
 

All the tips included with these headphones, all contained in a stylish holder.
 
 
Sound:

Now for the most important aspect of all audio products; the sound. As you can see I have split this segment into five parts, with additional thoughts in the final segment.

Lows: The bass is very tight and focused, maybe more than the preference of the average consumer. It definitely has a solid presence, but it manages this without overpowering the rest of the audio spectrum and doesn’t bleed into the midrange. The amount of lows might not be much for average consumers used to overpowering and muddy bass, but its tightness and presence contributes to this IEM bridging the gap between the consumer world and high-end audio.  

Mids: As these headphones feature a v-shaped sound signature, the mids are a bit recessed. They can also be described as warm, which is to my strong liking. Detail, while not winning over much more expensive options, is not a shortage here, and they deliver a present, crisp and clear experience. Also, it is worth noting that while the mids take a little step back, they do not suffer from the weird tonalities and other ruining audible factors.  If I had to nitpick, I would say the upper mids deserve a tidbit more presence. Nothing of major concern, though.

Highs: The treble, unsurprisingly, is boosted as well. Coming from a smoother pair of headphones, these initially sounded harsh. It is also worth noting that this is a common talking point of critics of these headphones. I personally do not believe in “burn-in” as a technical phenomenon, instead being process where your brain gets used to the sound. Anyway, I found the highs to be a bit harsh in beginning, but after some quality time with them, I found myself getting used to the treble. There is plenty of detail here, and they are just as crisp and clear as the mids. However, with me personally being a bit treble-sensitive, they can be a bit too much when playing content heavy on highs.

Soundstage: The soundstage is reasonably wide. Nothing extreme, but it is more than spacious enough, and I doubt that any of you will be dissatisfied with it. Instrumental layering and positioning is good and very satisfying.

 
Sound overall:

In my subjective opinion, these IEMs manage to deliver a balanced, yet crisp, detailed and powerful sound for a decent price. The lows should be strong enough for most’s liking, but also tight enough to not overpower the rest of the music. The mids are well balanced, rich and warm, but they are a bit recessed, which may be a deal breaker to some. The treble, like the lows, are a bit boosted, but after some time getting used to them they were nothing but a positive experience, livening up dull recordings with that extra bit of crispiness and spark. Overall, I thoroughly enjoy this product’s wonderful sound, and I find it to work well with all the genres I have thrown at it, including pop, electronic and more acoustical performances. They can’t measure up to the refinement offered by some other models, mostly higher priced, but I did not miss it at all.

 

These produce an excellent sound for most people, even from portable sources.
 
Noise isolation:

As a portable in-ear headphone, noise isolation is also very important when using it while out and about. For this type of usage I found it to be as well suited as most other in-ears. It does not feature active noise cancelling or anything like that. Instead, it has as good passive noise isolation as most other IEMs. They block out more than enough commute noise for a listenable experience. As always, some of the lower end gets drowned in the noise, but that is hard to correct without active noice cancelling technologies. The  way it is is more than acceptable in my opinion.

  Who’s this product for?

This product is for your everyday music lover, who is tired of the apple earbuds, and wants something more stylish and better sounding. They have also been described as perfect for “the audiophile on a budget”, which I can definitely agree with. As a first dip into the world high-res, audiophile goodness, these are excellent.

  Verdict: 4,5/5

 

P.S. For some reason the "audio quality" meter on this article is far lower than it should be. I rank the audio as 9/10.