Advanced Sound M4: A Promising First Product From The Audio Industry’s Newest Scion

Ever heard of Advanced Sound? Until this week, me neither. They are a relatively new company, with a fresh lineup of audio products, albeit a small one. Advanced Sound’s roots lie in the soil of crowd funding. Based in New York, the fledgling company chose a distribution model that would bring the best value to its customers, getting their initial funding from sites like Kickstarter and Indiegogo. This is a review of the only IEM they currently sell, the M4. While not for the treble-shy, the is a compelling offer for $40.

The M4 is currently for sale for $40. Pick it up at Advanced Sound’s official online store here.

Disclaimer: This review is based upon a sample unit provided to me by a manufacturer in exchange for my honest opinion and un-edited words. I do not profit in any way from the writing of the review. I would like to thank Peter at Advanced Sound for providing me with this sample unit.

Preference and Bias: Before reading a review, it is worth mentioning that there is no way for a reviewer to objectively pass judgment on the enjoy-ability of a product: such a thing is inherently subjective. Therefore, I find it necessary for you to read and understand what I take a natural liking to and how that might affect my rating of a product.

My ideal sound signature would be an extended sub-bass with a leveled, but textured, bass. The mids should be slightly less pronounced than the treble, but still ahead of the bass. I prefer a more bright upper range.

Source: The M4 was powered off of a Nexus 6P -> Creative Sound Blaster E3. All music was served as FLAC, ALAC, or as 320Kbps Mp3. I found the standard DAC/Amp inside my phone and PC to not be adequate to drive the M4 at near-peak levels of quality.

Sound Signature

Initial Impressions: These impressions were taken before I’d seen any FR response graphs or measurements.

I hear a thinned out mid-bass and sub-bass. Treble is pretty present, and is rather forwards. Articulation is good, with a surprising amount of detail retrieval in the upper range. The M4 is definitely bright, but lacks body in the lower-mids. The cold sound signature is reminiscent of a more gentle First Harmonic IEB6.

Treble: Songs used: White Flag, Arise, Outlands

I found the treble to be just right, as I prefer a bright sound signature. I first noticed a little hump around the 1–2kHz range. This boosts a lot of electronic sound effects and lends a helping hand to female vocals. High-hats punch through the din of the background well, and never sound cloudy. High-pitched strumming of acoustic guitars plays nicely in the foreground. Violins sound sweet and melodic, and are articulated well. I hesitate to say great, as it isn’t the implosion of awe you get from when listening to the RHA MA750i, and doesn’t have the kind of air I wished for, such as that of the AAW Q.

Mids: Songs used: The Drift, Jars, I Am The Highway

Mids are pretty good, and toned well. I like how they are placed overall, and enjoy their synergy with the treble. The M4 does recede the guitars a bit. In I Am The Highway, doing so lets little details like the plucking and metallic grinding of the pick against the strings come through in a way I wouldn’t expect from a $40 IEM. Vocals, unlike guitars, are in the front of the mix. I found them to be too soft against the background, but your mileage may vary.

Furthermore, while I like its articulation, I think the M4 could use more body. Thickening the lower-mids would do well by my ears.

Bass: Songs used: Lights, Kyoto, 99 Problems (Hugo Cover), Leave Me

Bass is too thin. I find that otherwise deep and full instrumentation is rendered fairly shallow on the M4, even when EQ’d. While I have no trouble hearing the sub-bass of Kyoto, I rarely feel it. Thankfully, it’s not all bad news. Mid-bass is decent, and provides a lot of detail. Bass guitars exist in the mix without washing together with the lower-mids, and are rather separate from the rest of the song in general.

99 Problem’s bass is textured and is placed well. It seems to exist parallel to the lower-mids and vocals. I also appreciate how the bass is “connected” to the rest of the sound. Some artificially boosted bass tuning that is oh-so-present in mainstream consumer IEMs causes an unnatural disconnected in the sound. I give Advanced Sound a thumbs up for engineering such an organic mixture, despite my desire for more bass.

Clarity: Songs used: Throne, Map of The Problimatique, I’m Not Alright

I did not find the M4 to perform too well on Throne. The intro was completely dry, and took on a jagged feel. Almost all detail became washed out. The song devolved into two layers: the bass guitar, and the vocal harmony + lead vocals. The M4 isn’t the only IEM I’ve tested that struggled with Throne, and that’s why I love using it as a test track. If you search through my previous reviews, you’ll notice I’ve only had two or three IEMs play the song back satisfactorily.

I’m Not Alright did much better. While I found a touch of distortion to come into play when the drum kicks during the intro/pre-chorus, I didn’t find anything blown out. I did notice that the background violins of the chorus were almost inaudible.

Map of The Problimatique, the simplest and least busy of the three test songs, performed the best. Separation is on point, and not blurry or smudged at all.

So what do these results mean? Put simply, the M4 punches at its price when playing very busy songs. I mean, there are even some instances where it beats out other budget IEMs, but its marginal.

Male Vocals: Song used: Hotel California, Ashes of Eden, Sunday Bloody Sunday

I find that the aggressive treble and upper-mid scaling of the M4 does indeed help male vocals. That being said, the sweetness I’d become accustomed to from the AAW Q is nowhere to be found. Artificial vocal harmonies can sound a tad metallic. I do, however, find the vocals to be better resolved on the M4 than other similarly priced IEMs such as the First Harmonic IEB6 ($30) and the MEE Audio M6 Pro ($60).

Female Vocals: Songs used: Stupid Girl, Sweet Escape, Need Your Heart, CrushCrushCrush

Female singers resolve particularly well on the M4. I can’t say for sure, but I assume it has to do with the 1–2kHz bump I mentioned earlier. The vocals press through songs well, and are toned beautifully; they just feel clean. The best words I could use to describe it is that they sound pure and effortless. Even the debbie-downer lyrics of Stupid Girl sounded as if they were sung by an angel, albeit a sadistic one.

Paramore’s Haley Williams’ voice was also presented well, and had many details exposed that I would have expected to be buried. Another credit I award to the engineers at Advanced Sound is the extreme lack of coloring in the vocals. Even the MA750i, which has generally been my go-to pair of “reference” earphones, sounds altered and unnatural at the hands of the M4.

Sound Stage

Up until this point, I’ve been nit-picking pretty hard. However, this is where I have my main complaint for the M4; Where’s the sound staging? Almost every song sounds entirely linear. There are some small exceptions with hard-panned left/right separation, but I feel that any IEM that wants to live up to the giant-killer moniker should be able to provide me with at least some depth and width. That being said, compared to other offerings in the M4’s price bracket, it does perform adequately.

Comparisons are done via the following format: I listen to a song on the headphone currently being reviewed. Then, I listen to the same song on the headphone I am comparing it to. If needed, I go back and listen to this review’s headphone again.

M4 v.s Alfa Genus V2, neutral filter ($60)

The most noticeable difference between the M4 and the Alfa Genus V2 is the bass response. Both mid-bass and sub-bass have more presence. The upper-mids and lower treble are far less aggressive on the Alfa Genus V2 than on the M4. Furthermore, I found that upper-treble extension and articulation is nearly identical. Higher-pitched string-based instruments are resolved more smoothly and with better tonality and timbre on the M4, barring the bass-guitar. I would recommend the M4 for acoustic songs, and the Alfa Genus V2 for electric ones. Due to the tonality differences, I find it difficult to declare a solid winner here.

M4 v.s Accutone Pavo ($50)

The Pavo’s bass response is similar in tonality and timbre to the M4, just more intense and more forwards. Resolution and retrieval are close on both IEMs, with the M4 leading in most cases. Little instrumental details such as the rattling of the strings of an acoustic guitar resolve much better on the M4 than the Pavo, owing to its very aggressive treble and upper mids boost. The M4’s sound signature is significantly more lean and brighter than that of the Pavo, but still has a charm to it. I prefer the Pavo for my alternative, classical, and electronic music, while I lean towards the M4 for my rock, metal, and classic rock.

M4 v.s First Harmonic IEB6 ($30)

The M4 certainly is bright, but it isn’t sharp. The IEB6 is sharp. It’s a little difficult to describe, since the IEB6 isn’t sibilant. The bass response on the IEB6 is shallower than on the M4, and the treble doesn’t extend as high. The IEB6 does lead a little in the mids, creating more convincing guitars and violins. However, I would not trade that for the much better overall presentation offered the M4. In my books, the M4 has a solid lead over the IEB6.

Packaging / Unboxing

The unboxing experience was relatively basic, and reminiscent of the Ghostek Turbine (another $40 IEM). The driver housings came nestled tightly in foam cut-outs, with the cable being pre-coiled inside the M4’s circular carrying case (another similarity the M4 shares with the Turbine).


Construction Quality

I have almost no qualms with the construction of the M4. Its chassis is built from what looks like aluminum. The texture is semi-matte, so it’s rather hard to tell from touch alone. The cable is connected via a fairly competent strain relief system to the driver housing. I’m not too worried though, as the cable is insane for a pair of $40 IEMs. It’s a twin-braid, and is coated in some fairly basic plastic.

However, it looks pretty stellar. It doesn’t really tangle, regardless of how long I’ve had it in my pocket. Unfortunately, as someone who wears the cable of their IEMs under their shirt, I find the cable uncomfortable as its uneven surface tends to chaff my skin when walking. The 3.5mm jack is right-angled, and case-friendly. It’s coated with some thick plastic, so don’t worry about longevity on this thing. For $40, you will be hard pressed to find something as well put-together as the M4.


The M4 comes with a plethora of eartips. However, I’m sticking with my trusty old Comply. It really helps for people like me who have two differently shaped ear canals.

The M4 is so light it disappears almost entirely once you get a good seal. However, it does protrude rather far out of the ear. This means that you are going to have a hard time sleeping with these in your ears, even when laying flat. Furthermore, it makes the M4 very susceptible to being pulled out of your ears when downward force is applied to the cable.


Advanced Sound equipped the M4 with a mono-button universal control unit. Your standard pause/play/fast-forward functionality is present on both Android and iOS systems. However, volume control is not.


One thing to note is that the earbuds I received came disfigured and misshapen. Either I got a bad unit, or the guy who packages the eartips wasn’t having a good day. If you are dead-set on not using Comply, your experience may vary.

Look at the funny shapes


Simply put, the M4 is my new favorite IEM under $50. It’s a crowded price-segment, so competition is fierce. While there are certain situations that can cause the M4 to struggle to resolve everything without distortion, I find that the detailed and colorless sound signature continues to make the M4 my IEM of choice when I’m going on an adventure or when I’m worried about taking my more expensive IEMs out and about. Good job Advanced Sound. I look forward to seeing what you’ve got in store for us in the future!

EDIT: Sorry M4, you’ve already been beaten by the Hidizs EX-01!