Headphone Review: ACS T15

Radiohead starts up their smooth, groovy tune. Muse plays live in front of millions. U2, artistically brings new light on a new classic, and even introduces a new one to the entire world. All these bands are known, some old, some new, some in between. All three of these bands also look at ACS for their on stage monitors that they use. Since the mid 1990s, ACS has been providing the world of custom monitors, however, these can prove expensive, and to an end user like us, not entirely worth it depending on how dedicated people are to getting the best audio. However, ACS has released their first universal IEM which is cheaper and has a closer resemblance to what we know as IEMs today. Targeted at the general public, the T15s offer a petite design, amazing audio reproduction, respectable build quality, unbelievable comfort, and an overall great bang for the buck.  Read on for the full review: 


  • Driver Type: Single Balanced Armature
  • Frequency Response: 16 Hz – 20 kHz
  • Sensitivity: 109 dB
  • Impedance: 13 ohms / 41.3 ohms

In The Box

  • ACS T15 Universal IEMs
  • 2 Sets of triflange tips (S/L)
  • 3 Sets of Single flange tips (S/M/L)
  • Hard-shelled carrying case

The ACS comes with enough accessories to get the ball rolling.


Petite, tiny, and miniscule. These are three words that could easily describe the design of the ACS T15s. They are small, so there isn’t much to actually see. However, what you do see looks nice and pleasing. It’s not that shiny, bright, and in-your-face pleasing; it’s more of the warming, nice feeling. The black housings on the IEMs stand out really well, they take the shape of any other IEM you can see. On each side of the headphones is the ACS logo.

The miniscule T15s still look aesthetically pleasing.

Now, there are no physical right or left markers that are visible until you look close up. ACS decided to go with the old-school red-right and blue-left markers for the left and right instead of the standard L and R markers used on many IEMs today. I do prefer a red-blue marker versus an L-R one since it is more apparent, and at the same time hidden from the IEMs themselves. The markers are also placed somewhere that isn’t too straightforward either; on the nozzle.

The red and blue markers that show you left from right are placed on the nozzles of the IEMs.

Design: ★★★★★


ACS has good ties with Etymotic since they are the ones in charge of the custom tips that are available for Etymotic IEMs. Now, I make this comparison in this section because the T15s sound a lot like Etymotics, of course ACS does put some minor signature changes which are well welcomed overall since they try to fix the problems that Etys have.


Etymotic bass is known to be extremely light, and in most cases way too light lacking impact. At times, they lack a body as well. ACS did a good job fixing one of these problems, but not being able to capitalize on the other. The T15s do give pretty accurate low-end response that provides listeners with a little more quantity in the mid-bass part of the spectrums. The end result is much better impact. The texture remains unchanged, which is amazing when it is present. What still isn’t fixed entirely, but somewhat improved is the bass body on the ACS. These improvements are great overall, but the body still isn’t quite enough to obtain that bass that all music requires. However, the bass quality overall is still extremely great. It improves upon Etymtoic’s bass, but not enough to earn the perfect score.

Bass: ★★★★½


The mid-range also reminded me a lot of HF2 mid-range. Again, these are slight improvements if you find them to be. The mid range is still extremely detailed and articulate. There is a slight improvement in the actual imaging and positioning of the instruments, but not much. The separation is still there, like with the HF5s. Even with all this detail and clarity that the T15s have, they don’t stuff them in a gun and blow them in your face like the HF5s do, which is actually a good thing. The midrange is slightly improved compared to the Etys, but this can only be heard if you listen to them hand in hand. Otherwise, there really isn’t any difference. The mid-range on these is just perfect to the touch on the T15s.

Mids: ★★★★★


Once again, there a slight improvement with the high-end in comparison to the HF2s, at the same time, there isn’t. I found the HF2’s treble to a little too aggressive, I even found the B2s to be slightly aggressive as well. I didn’t really find these to be aggressive at all. However, they aren’t as refined as the B2 or HF2 treble. I was hoping for a slightly more delicate sound to the treble. These go slightly overboard and give more of an edgier sound to them. Don’t get me wrong, they are still enjoyable with amazing clarity and details. They sparkle and shine like a starry night. The high-end quality of the T15s are on par with the HF2s, fixing one problem with the HF2s, but creating another while doing it. They are still great nonetheless.

Highs: ★★★★½


ACS ensured that the T15s isolated as well as their customs did when they designed them. Custom are really great with isolation, but they still are not the best (Etymotic universals still isolate a little better). These require deep insertion so they will isolate extremely well. They are one of the better IEMs when it comes to reducing the angry customer next to you while you are waiting in line.


Microphonics on these is something that can still be adverted by wearing the IEMs over the ear. Wearing them down does still generate a lot of cable noise. Bone conduction, that thump you get from walking or running, still can’t be rid of, but most, if not all, IEMs still do this. I do wish that ACS did include a clip with their IEMs.

Overall, the sound signature of the ACS T15s is reminiscent of the Etymotic sound. That isn’t even a bad thing at all since the HF2s have been known to have some of the best sound quality around, especially for the price. These follow good footsteps and fill them pretty well while doing it.

Audio: ★★★★½


The T15s come with some pretty big build, despite their diminutive size. They are not perfect in terms of build, but definitely aren’t an IEM to pass up because of weak build. They do come accompanied with a case, which is helpful in the long run. The case is small and portable, so it shouldn’t be a problem to carry around. If you have a Nano or Shuffle I would see no problems fitting either of those in the case in one of the two pockets that allow you to hold extra accessories.

The case that these come with is simple, it’s not too large, but not too small either.

Looking at the headphone jack, you’ll notice that the jack itself comes at a nice 90 degree angle. This is great as angled jacks are physically better than straight ones in terms of build. The rubber on the jack is extremely tough and the strain relief continues this nice tough attribute while still being flexible. The gold plating seals the deal in terms of the headphone jack’s build.

The headphone jack is built perfectly.

Slide up the T15s, you’ll see a nice cable. The bottom half is thicker than the top, however, it still isn’t the thickest on either end. Although I would like it thicker, it doesn’t need to be since the Kevlar reinforcement is more than enough to keep it from snapping. I do have one complaint though, the cable comes wrapped up, and the cable never really leaves that wrapped shape. I always found the cables would fold themselves up during use. At times this could cause the cable to tangle.

The earpieces are extremely nice and small. This doesn’t mean they are weak by any means. Even in their small size, the plastic on the housings seems really strong. They give you adequate room to pull out the IEMs, despite the deep insertion, through the body of the IEM. This especially good knows that there is no strain relief on the housings. This is the biggest letdown of the build.


The housings have no strain relief which may cause problems in the long run.

Overall, the build is nothing to laugh at, but there are some places that can use some reinforcing. The headphone jack is the ideal jack I’d want on an IEM. The cable would be perfect if it didn’t fold itself, but the lack of a strain relief on the housings scares me a bit.

Build: ★★★★


OK, this is where the minute size plays a huge role on these ACS’: Comfort. Etymotics required deep insertion which could be irritating at first. They really didn’t really have the widest tip selection either, nor did they have single flanges, which I find to be much more comfortable than most others. ACS provides a total of five tips: two are triple flanges, while the rest are single. I’m using singles, and they are so comfortable. Their diminutive size allows me to lay down with them if I wished too. The tips, in conjunction with the small mass of the headphones, both play a huge role in allowing the most comfort that can be obtained earning it a perfect five.

The IEMs come with 5 tips. I’m sure that anyone can find one that is extremely comfortable, but also sounds good.

Comfort: ★★★★★


Overall, these are an upgrade to the Etymotic HF5s, so if you are a fan of those, you may be interested in giving these a go. However, these cost a little more than the HF5s, which is the turnoff here. While the HF5s do MSRP at 180, you can find them easily for around 100. The T15s will set you back 220 dollars. Are they worth it? I say yes. If you are looking for something that is an improvement to the HF5s, but don’t want to splurge 300 bucks on the ER4s, then these can actually suite a lot of people. However, they still aren’t the best bang for the buck as something like the Brainwavz B2 will sound better overall for 50 to 100 dollars less. Although they aren’t the best bang for the buck, I still deem the T15s worth their price as they do offer amazing audio quality and comfort.

Value: ★★★★½

Final Thoughts

ACS took a huge step into the universal IEM world, and what a big step it was. They were able to push out a monitor that could target dedicated listeners with amazing audio quality. The headphones are small and comfortable, but also durable as well. If you are a fan of the Etymotic sound, and are looking for a new IEM, this may not be a bad choice to go with.

I’d like to thank Jessica for the review sample.

Overall Score

ACS T15 Universal IEM

† All prices are in US currency.
This review was written by the iFans.com Review Team. Cumulative scores are rounded to the nearest half or full star.
This accessory, product, or app was received as a sample. Thanks Jessica for the product sample.
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