Home » Reviews » Custom IEMs » Ambient Acoustics AM4 pro Custom In-Ear Monitor Review

Ambient Acoustics AM4 pro Custom In-Ear Monitor Review

Ambient Acoustics AM4 Pro Custom in-ear monitor (CIEM)

I first found Ambient Acoustics in my search for custom IEM manufacturers in 2011.  At that time flagship product was the AM2.  I contacted them in English to get more info but never received a response and let it go.  Once I found out they now had 3 and 4 driver models so I decided it was time once again to reach out, but this time in Russian thanks to a friend.  This time I did receive a response and found out more.  The regular models have enhanced bass while the pro models are more of a reference design.

In my email exchanges with them, all in Russian, they told me they are interested in selling internationally and can take orders in English.  After further communication, I was sending in my ear impressions for the AM4 pro.  I chose between the bass enhanced AM4 and the more neutral AM4 pro, and decided on the neutral presentation since I know how good something neutral can sound when done right.  All of this was done in Russian, but their site is supposed to be updated with English also, and a way to order internationally.  A few months later the monitors arrived sans the typical accessories, as they informed me they would be sending only the monitors.



Ambient Acoustics website can be found here, and although it is in Russian, Google Chrome can automatically translate it for you.  They can communicate in English, Russian, and Ukrainian, however currently their order form is only in Russian and since it is a PDF, it can’t be translated in Chrome. The AM4 Pro cost 4400 UHA, which translates to just under $500 at the time of review.  NOTE: The AM4 Pro has been replaced by the AM4 MusicEdition which has more bass and smoother treble. Pricing is the same.

Options: The cable can be black, white, beige, or silver.  There is an option for cable down configuration, however the cable will not be detachable.  Artwork.

Warranty: 30 days for fit, 1 year for parts.



The AM4 pro uses 4 balanced armature drivers in a 3-way configuration with an acrylic shell, 3 sound tubes, and has a detachable cable.  The cable is non-standard; see the cable section for more information.

The outside finish of the AM4 pro is very nice, with no external artifacts, a perfect fit from my impressions, and the canal length is longer than many others such as the JH16 and IERM while not as long as the musicians fit 8.A or the SE 5-way.  In other words, the canal length is a great length that allows for quick insertion along with a better seal and noise isolation than the shallower insertion CIEMs.  Note that I do make ear impressions that are very deep.

On to the internal build of the AM4 pro.  The internal drivers and electronics are well organized and positioned.  The internal portion of the shell isn’t perfect, as upon close inspection the inside of the back plate is not smooth.  This doesn’t affect the overall quality look or detract from the outward astetic qualities of the AM4 pro unless you inspect it closely and compare it with something that is smooth both inside and out, such as the Dunu DC4 and Heir Audio products.  Fit & finish score: 8/10


The AM4 comes with a Dolphin case, cloth pouch, cleaning tool, and desiccant, however my AM4 pro only came with a cloth pouch, so I have used the accessory images from the Ambient Acoustics site.



The cable is unlike any custom IEM cable I have seen before as it is similar to that of the clear MEElectronics M6 cable, but thicker below the Y-Split.  This cable appears more durable than a standard custom IEM cable, but the cable has a mind of its own, being very elastic and not wanting to stay wrapped.  While that is a problem when trying to put the AM4 pro away, the cable is OK when in use.  Ergonomics of the cable are similar to the Minerva and better than the i9pro, plus you can replace the cable if the ergonomics bother you.  This is a clear cable that won’t turn green over time and does have a robust feel.



Isolation is a bit above average for an acrylic shelled custom IEM with a hollow shell due to the slightly longer than average canals.  6/10



Disclaimer: My review is a comparative review, and since I have many similarly priced custom IEMs, my perspective is based on equal competition.  My goal is not to tell you how great the product under review is, but to explain the sound signature and characteristics as well as bring you a balanced account of the strengths and weaknesses to help you decide if this particular custom IEM is for you.  This critical look at the product will almost always result in both strengths and weaknesses being revealed.  It is my firm belief that you should buy a product based on the sound you prefer, or the sound for your particular purpose.  If you don’t know what you want, read through the reviews and try to imagine if you would like the described aspects of the sound.

Quick reference: My review techniqueThoughts on reading a reviewCustom IEM information

The AM4 pro received 100+ hours of burn in as is customary before I do my serious listening.  The following custom IEMs were used for comparison: Dunu DC4, Alclair Reference, Fabs Fabulous Earphones, Thousand Sound TS842, Minerva Mi-3, Dream Earz aud-5X, and Wan Xuan i-9pro.  After comparison with the previously mentioned CIEMs, Even though in different price points, I decided to also compare with the Ultimate Ears IERM and ACS T1 Live! as well as the Vsonic GR07.

The AM4 pro is designed with a balanced sound across the spectrum and upon my first listen that is what I got.  I was pleasantly surprised with the overall sound quality and the sound signature balance gave a great tonality to the presentation with no glaring weaknesses.  The monitor was very listenable out of the box.  Over time I didn’t hear much, if any change, however I really didn’t listen for any.


Bass: Bass is near neutral with a slight lean to the enhanced side, but quite capable with the ability to recreate slam, rumble, and impact when the track calls for it.  If you think the CK10 or ER4 have neutral bass, the AM4 pro will seem enhanced, however it is more that those two don’t have the capability to sustain bass notes to produce the full body and weight that is in the original track.  While the bass is close to neutral, the dynamic range can make bass heavy tracks sound enhanced compared to many lower cost headphones and IEMs that don’t have the dynamic range that the AM4 pro has. The bass output capability is impressive for the sound signature and price level, but does trail the two dynamic driver CIEMs I have in the price range and the aud-5X.  But the difference isn’t huge with a source that has driving power.

Detail levels and texturing is very good with the ability to rumble yet recreate the small nuances within the music from the well controlled drivers.  It is not necessarily warm, nor lean, just neutral.  Speed is excellent with the ability to keep up with just about anything, but it isn’t the fastest out there, which is a tradeoff due to the other fantastic qualities.  The bass starts to gently roll off at 30 Hz, providing sensation down to 16 Hz and still having good weight at 20 Hz.  While not the highest performing in the bass department, the combination of control, detail, texture, and capability place it in the to p 3 within the price range.


Midrange: Compared to reference monitors such as the Alclair Reference and IERM, the midrange is more forward and quite similar to a presentation such as the ACS T1!, which is a stage monitor.  Many CIEMs in the price range are more mid-forward such as the DC4, Fabs, Mi-3, and SA-12 for example.  Depth of the presentation is the best in the price range, close to the EM3 Pro, which allows the AM4 pro to image well and present music with excellent layering.  Compared to others within the price range, the resolution within the soundstage, instrument separation, and instrument detail are all above average.  Tone of vocals is spot on with both male and female vocals, providing a balance of clarity, warmth and brightness to vocals that all in a beautiful balance, not overdoing or under doing any part of the spectrum.  Integration and balance of the midrange with the rest of the spectrum is excellent. The bottom line is the midrange is immersive, accurate, and musical with a presentation somewhere between a stage monitor and studio monitor.


Treble: Rounding out the balanced frequency response, the treble provides a bit of brightness, but not to the level of the IERM and TS842 and has more treble presence than others such as the TS842 and DC4.  The treble has air, detail, good extension, and very good note attack and decay leading to a pleasant, articulate, and realistic sound.  Detail levels are good considering the note decay, as brighter sound and faster decay accentuates the details, but doesn’t sound as natural.  With a high quality, natural sound, the treble provides the finishing touch to the excellent presentation across the entire frequency spectrum.

As the source quality decreases and/or the volume increases, the treble becomes more analytical and sharper, reducing the overall quality that is so good at lower volumes.


Presentation: Every part of the frequency spectrum comes together quite well While there is nothing wrong with any part of the frequency spectrum, the real strength of the AM4 pro is the overall presentation.  Everything is integrated together quite well resulting in great coherence.  The forward midrange gives more of a stage monitor sound than a studio reference monitor, but it could still work for the studio.  Depth of the presentation is impressive, rivaling CIEMs with prices over double, but the width is more reminiscent of the price range. This impressive depth of presentation, like the bass, doesn’t come through unless it is in the recording, so it doesn’t sound off when tracks don’t have the depth.

Note decay is not analytical, but not too smooth; a nice balance that is detailed, but not in an analytical way.  In a similar fashion to the presentation depth, the AM4 pro is one of the better performers as far as detail and resolution goes, but still lags behind CIEMs at double the price and more.  The AM4 pro is revealing yet forgiving of poor tracks.  Speed is fine for all genres, and while it doesn’t sound slow, other CIEMs such as the 5X, TS842, and more expensive CIEMs have a better sense of speed.  Dynamics are excellent and transparency is above average.


Volume performance: The AM4 pro excels at low to medium volumes, with a full sound at quieter volumes than most BA CIEMs.  At extremely low level listening the AM4 pro has similar issues to other IEMs, which is there isn’t enough power to generate enough power for a full sound.  As you turn the volume up the exceptional clarity, focus, and resolution within the soundstage start to get a bit congested in comparison with the lower volume levels.  This loss in clarity isn’t to the extent of some others I have heard, but is still there.  The treble that is smooth and liquid, yet detailed at low to medium volumes becomes a bit harsher at louder volumes.  I can’t listen at the volume where there are issues for more than a minute or two.


Sound Summary: The AM4 pro has a sound signature that is on the brighter side of neutral with a very good balance and integration across the frequency spectrum.  The midrange is presented in a forward way, more forward than the reference monitors I used for comparison, but not as forward as some of the audiophile models, which make it great for stage use as well as a reference, or just for music enjoyment.  The bass is very capable, the midrange has an impressively deep soundstage, clarity is great and resolution is high for the price while the treble has an excellent note decay, all leading to a tonality that just sounds right.  From a technical performance standpoint, the AM4 pro punches above its price and holds up quite well when compared with monitors double the price.  Overall, the AM4 is an impressive custom IEM that will please many.

Page 2: Comparisons, source matching, and summary





Having a life-long love of high-quality audio and gadgets, average_joe got back in touch with his audiophile side after a hiatus caused by life. His focus became headphones and related gear as the size and price fit his life better than home audio. He believes the entire audio chain is important, and likes to continue to think past the headphone and on into the head, as he believes understanding the details of how we hear will lead to a better audio experience.


Leave a Reply

Your email address will not be published. Required fields are marked *

Recent posts