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ACS Custom T2 Classic Custom-Fit In-Ear Monitor (Playback 61)

ACS Custom T2 Classic Custom-Fit In-Ear Monitor (Playback 61)

The name ACS Custom might not be the most well-known in today’s custom-fit in-ear monitor marketplace (that title probably belongs to Ultimate Ears), but the firm is certainly known by the company it keeps, with a client list that includes the BBC (BBC Orchestra, BBC Radio, and BBC Singers), Pink Floyd, Radiohead, U2, and many more. What’s significant, I think, is that many of these famous ACS Custom endorsers are known for creating music that is not only popular, but that places a premium on sound quality. To better serve its worldwide customers, ACS Custom maintains offices and in-ear monitor manufacturing facilities in multiple locations throughout Europe, the US, South Africa, Australia and New Zealand.

I had the opportunity to catch up with one of ACS’ principals, Dr. Craig Kasper, at the 2012 CES Show, where I learned about ACS. Much like the Chicago-based firm Sensaphonics, ACS believes strongly in building its in-ear monitors with earpieces made of soft-gel silicone materials, rather than the more commonly seen solid acrylic materials. As you’ll learn in this review, this particular design touch influences the performance capabilities of ACS monitors in several important ways, especially in terms of allowing an extremely comfortable fit with very high levels of noise isolation. I asked Dr. Kasper if he would recommend any particular ACS model for audiophile applications where a key objective would be to obtain the most neutral, accurate sound possible. Dr. Kasper recommended ACS’s T2 Classic Dual Driver model ($799), indicating that it was, at the time, the ACS model with the most accurate overall tonal balance.

ACS Custom T2 Classic Custom-Fit In-Ear Monitor (Playback 61)

The T2 Classic is, at least in terms of price, the middle model in the ACS lineup, positioned above the T3 Classic Single-Driver monitor ($479) and below the T1 Classic Triple-Driver monitor ($999). At first blush it might seem odd that the middle model in the range would be more accurate-sounding than the “flagship” model (at least in strict audiophile terms), but in fact this arrangement is pretty common in the world of custom-fit IEMs. What goes on is that top-tier IEMs are often designed more with the needs of performing musicians in mind, rather than targeted for customers who will use their IEMs primarily for listening to recorded music. Indeed IEMs designed for use as stage monitors often feature frequency response curves that deliberately incorporate certain strategically placed “colorations” with an eye toward helping musicians hear clearly even in the presence of extremely loud stage environments.

 

We reasoned, however, that most Playback readers would purchase in-ear monitors for purposes of listening to recorded music—sometimes in quiet environments, but occasionally in more noisy settings (e.g., flying on planes or riding on trains). With this thought in mind, we requested a set of T2 Classic monitors, which ACS Custom graciously provided for us to review.

ACS Custom T2 Classic Custom-Fit In-Ear Monitor (Playback 61)

OVERVIEW

Consider this product if:

  • You prize IEMs that offer a remarkably well sealed, comfortable, and ultra-secure fit with excellent noise isolation. The soft gel silicone earpieces really do make a big difference.
  • You want an in-ear monitor with a delicate, warm, vibrant, and highly engaging sound. But note: The same upper midrange/lower treble emphasis that makes the T2 Classic sound “vibrant” can sometimes—on certain high-energy transients—make this IEM sound slightly “spitty.”

Look further if:

 
  • You expect your in-ear monitors to come with user replaceable signal cables (by tradition, ACS’ Classic-series monitors come with non-detachable, “embedded” cables). Note, though, that ACS’ new Live-series models, which are slightly more expensive than the Classic models, do have detachable cables plus other features. Further, ACS may soon offer standard T2 models with detachable cables.
  • You’re after maximum sonic neutrality. If studio monitoring-grade accuracy is what you seek, Ultimate Ears’ In Ear Reference Monitor remains our go-to choice.

Ratings (relative to comparably-priced custom-fit in-ear monitors)

  • Tonal Balance: 8.5
  • Clarity: 8.5
  • Dynamics: 9
  • Comfort/Fit: 10
  • Sensitivity: 9.5
  • Value: 9.5

FEATURES

ACS Custom T2 Classic, technical highlights include:

  • Dual balanced armature drivers said to deliver the most neutrally balanced sound of any of the Classic-series ACS models.
  • Earpieces made from flexible “40 Shore Silicone”, which is a material ACS describes as the softest medical grade silicone available in in-ear monitors. This choice of material is, in our view, extremely significant in that it yields an earpiece whose shape is precise, yet that can bend and flex in much the same way our outer ears do. ACS claims its earpieces offer superior fit, long-term wearer comfort, and noise isolation—claims our listening tests tended to bear out. In particular, we found the ACS earpieces were able to maintain an excellent seal and very good comfort for the wearer, even in circumstances where the wearer’s jaw moved to open or close (conditions that can, with some hard-shell earpieces, cause temporary discomfort or a momentary loss of the all-important in-ear seal).
  • Kevlar-reinforced signal cables with anti-noise sheaths. The T2 Classic cables are “embedded,” meaning they are not removable. Note, however, that ACS does now offer a new T2 Live! model ($999) which incorporates removable signal cables, but that also incorporates other features such as built-in ambient sound monitoring mics that may or may not be of any interest to Playback readers. (When used with an optional ACS portable amp/mic mixer, the ambient mics provided in the T2 Live! model potentially allow performing musicians to hear a mix of ambient stage sounds along with a stage monitor mix from the soundboard.). ACS’ Craig Kasper advises that, “We are now starting to manufacture the standard T1 and T2 with detachable cables and no ambient mic, targeted at other segments of our user base outsider of touring artists.”
  • As a clever detail touch, the signal cable is fitted with a small retaining strap fitted with snap closures. When you’re done listening to the T2’s you simply coil up the signal cables and use the built-in strap to keep them coiled.

Accessories

  • Leather-like semi-hard shell road case, which consists of a two-chamber inner drawer and an outer sheath.
  • Leather-like soft carry pouch.
  • Cleaning tool/wax pick.
  • Small pouch of desiccant material to keep the IEMs dry.
  • Tube of comfort cream—a gentle lubricant that can be applied to the earpieces to ease insertion/removal.

 ACS Custom T2 Classic Custom-Fit In-Ear Monitor (Playback 61)

EASE OF USE

As we have found in the past when testing in-ear monitors with soft gel silicone earpieces, there is a bit of a learning curve involved in mastering proper earpiece insertion and removal techniques. As a general rule, silicone earpieces offer a fit that initially seems a bit tighter than you might find with monitors that use acrylic earpieces, but with the benefit that—once properly seated, the earpieces give you a more comfortable, more flexible, and better-sealing fit. One added point to bear in mind is that ACS’ “Full Concha” earpieces may need to be flexed just a bit in order to allow the uppermost parts of the earpieces to slip under the folds of your outer ears; this sounds weird on paper, I know, but in practice you may experience one of those “Aha!” moments when the earpieces finally snap into place. Don’t skip over the important step of tucking the top edge of the earpieces under the folds of your outer ears; in our experience, this small but worthwhile step proved one of the keys to getting maximum performance from the ACS monitors.

 

Our findings: The ACS T2 Classic may take some effort to learn to fit properly, but it rewards the user with an incredibly comfortable and ultra secure fit, plus ACS states that its earpieces use a so-called “Full Concha” ear mold. In practice, this means that the ACS earpieces extend upward further than most other custom-fit units do, meaning that the earpieces actually tuck under folds in the outer ear and thus are effectively “locked” in place when properly fitted. We found this arrangement gave excellent noise isolation and an incredibly secure fit, yet one that is not restrictive and that allows relatively easy earpiece insertion/removal excellent noise isolation. The T2, along with Sensaphonics’ 2MAX monitor, provides the best noise isolation of any monitor we’ve tested.

SONIC CHARACTER

About our listening tests: For purposes of this section of the review, we listened to the T2 Classic through are variety of amplifiers and source components, including:

  • An ALO Audio Rx Mk3B fully balanced portable amplifier fed by the combination of an iPod (loaded with lossless and/or full CD-res WAV digital audio files) and a Cypher Labs AlgoRythm Solo portable DAC.
  • A Ray Samuels Audio SR-71B Blackbird fully balanced portable amplifier fed directly from an iPod (loaded with lossless and/or WAV digital audio files).
  • A NuForce Icon iDo DAC/headphone amp fed by an iPod (loaded with lossless and/or WAV digital audio files) where the NuForce DAC—not the iPod’s built-in DAC—handled the job of decoding digital audio files.

We listened to the T2 Classic in comparison to many custom-fit IEMs and top-tier earphones, but focused especially on comparisons with the Ultimate Ears In-Ear Reference Monitors (IERMs), which serve as Playback’s reference standard for overall neutrality of tonal balance.

ACS Custom T2 Classic Custom-Fit In-Ear Monitor (Playback 61)

And the findings, please: Let’s begin by acknowledging that one key aspect of the ACS sound is the almost otherworldly, ultra-quiet listening background these monitors provide. In our experience, the T2 Classic has only one peer in this regard; namely, the Sensaphonics 2MAX/2XS monitors, which—like the T2 Classic—use soft gel (cold cure) silicone earpieces. In terms of absolute quietude, though, the factor tips the scales ever so slightly in favor of the ACS monitors is their “Full Concha” earpiece design, which gives a secure seal no matter how vigorously users might move around while listening. It sounds a bit hokey to say, but after a few minutes the T2 Classics almost seem to become part of you.

The T2 Classic offers what appears, at least in broad strokes, to be generally neutral tonal balance, but with three small yet audible strategic deviations from strict textbook neutrality. First, bass—and specifically mid-bass—is warmed up just bit in what we presume is an effort to give the T2 an extra touch of mid-bass weight and warmth. Second, upper mids and lower highs are likewise given a dab of extra emphasis, not enough to make the T2 Classic sound overtly bright or edgy, but enough to impart a heightened sense of focus and clarity. The one observable downside to this approach, however, is that the T2 can make upper harmonics of notes as well as certain hard, sharp transient sounds seem disproportionately forward sounding or even a bit brittle-sounding on some recordings. Third, uppermost high frequencies through the T2 are just slightly subdued—a quality that some listeners might scarcely notice, but that some might find can make high frequency ambient cues or the “air” in recordings sound truncated to some degree.

 

On the whole, the T2 offers a warm, vibrant, and engaging sound, though one that can exhibit occasional upper midrange/lower treble rough spots in the form of the aforementioned brittle-sounding transients. Don’t get me wrong, though: the T2 is for the most part a very enjoyable monitor to use, and one that will win its fair share of hearts, minds, and ears with a sound that is, in a rather subtle way, a bit larger than life. It’s just that critical (or perhaps I should say “hyper-critical”) listeners will find some shortcomings, as noted above.

By comparison, Ultimate Ears’ IERM was and remains our reigning “neutrality” champ. In practice this means the IERM offers a smoother, more evenly balanced response curve—especially in the critical midrange-to-upper midrange and upper midrange-to-treble regions. While the T2 Classic can, in certain respects, sound more exciting to listen to, there is a certain ineffable rightness to the IERM’s midrange and high frequency tonal balance that reminds me of the sound of very costly high-accuracy monitoring loudspeakers. Some people love the sound of accurate monitors, while others might prefer the warmer, more vibrant (albeit somewhat more colored) sound of the T2 Classics.

Down low, the IERMs just plain have less bass (or at least less overt mid-bass) than the T2s, though I think those who know and love bass instruments will find the IERMs are actually truer to sound of the real thing. This is an area where I realize many listeners prefer a hint of elevated mid-bass, which is precisely what the T2 offers. The IERMs, in contrast, offer what is arguably a more fundamentally natural and realistic bass sound, but one that—for better or worse—gives listeners only as much bass output as is provided in the original recording.

Finally, the IERMs deliver an extra—and I would argue accurate—measure of high frequency extension and air that the T2s cannot quite match. As I mentioned above, this is a relatively small and subtle difference that some listeners might not notice at all, but that others might. It’s a difference that gives the IERM a small edge in terms of conveying an overall sense of the acoustics of the original recording space.

ACS Custom T2 Classic Custom-Fit In-Ear Monitor (Playback 61)

MUSICAL EXAMPLES

Let me illustrate some of the comments I made under SONIC CHARACTER, above, by describing the T2 Classic’s performance on several real-world pieces of music. First, as a test of overall clarity and neutrality, I put on the track “Timeless” from Larry Coryell, Badi Assad, and John Abercrombie’s Three Guitars [Chesky]. As the title of this album suggests, this album focuses primarily on the distinctive sounds of three masterful, but very different, instrumentalists, each playing acoustic guitar. It perhaps goes without saying that all three instruments play in the exact same pitch range, so that the only way to distinguish one guitar from another is to pay attention to subtle voicing differences between the instruments, to variations in playing technique as practiced by the individual artists, and, of course, the position of each instrument within the broader soundstage.

 

The T2 Classic did a very good job of differentiating the soundstage positions of the guitars and guitarists, and of highlighting signature differences in the artists’ playing styles. In a sense, the T2’s subtle band of upper midrange/lower treble emphasis worked in a complementary way, here, making differences in plucking techniques or fingering styles stand out in sharp relief. The downside of this band of emphasis, however, was also apparent, as the T2 tended to overemphasis (albeit in a subtle and not terribly oppressive way) certain fast-rising transient sounds, giving them an exciting but also unnatural “jangly” quality.

Three Guitars does not feature much in the way of mid-bass content, but even so the T2’s subtle touch of mid-bass emphasis made itself felt by accentuating certain low-level bass hall resonances, giving the presentation a very subtle “wash” or low-end warmth that made the recording venue sound, if anything, a bit darker and more intimate than it otherwise might. While one could argue that this presentation is not, in a strict sense, entirely faithful to what’s on the record, it is a presentation that complements the music in an appealing and engaging way.

I tried the same track (“Timeless”) through my Ultimate Ears In-Ear Reference Monitors and found that the sound, while losing most of the euphonic embellishments offered by the T2 Classic, at the same time seemed more accurate and naturally balanced, with a just-right quality of midrange balance, beautifully extended highs, and no “jangly” or “edgy” sounds at all. The guitars, in short, sounded like themselves, which is high praise indeed. Down low, the IERMs likewise lost some of the desirable warmth and bass-enriched intimacy of the T2 Classics, but in return gave a more natural and, in the end, more believable sense of three master guitarists performing near the front edge of a stage.

I performed this same type of comparison by listening to the lovely live jazz recording of the Joe Wilder-Marshall Royal Quintet performing “Mood Indigo” from Mostly Ellington [Blueport Jazz] through both the T2 Classics and the IERMs. Much like Three Guitars, Mostly Ellington gives a natural sounding, up close and personal look at jazz performers in a live setting. Once again, the T2 Classics upper midrange/lower treble emphasis made certain low-level performance details, such as reed noises from a saxophone or embouchure noise from the mouthpiece of a trumpet, stand out prominently, while the IERMs gave those same details an equally finely resolved but more naturalistic presentation. The telling difference, though, is that the T2s sometime overemphasized the details they highlighted, while the IERMs did not. An example, here, would be the way the T2 sometimes made saxophone reed sounds, which should be very subtle and almost subliminal, stand out with a very pronounced “buzz” that could be distracting.

 

The Joe Wilder-Marshall Royal Quintet does feature an acoustic bass, which the T2 Classics rendered with a pleasing degree of extra underlying warmth and darkness that complemented the intimate setting in which the recording was captured. With the IERMs in play, that extra layer of comfortable warmth and darkness went away, but with the result that the bass—though slightly less weighty than before—otherwise sounded more realistic and believable.

Because the colorations of the T2 Classic are subtle and for the most part complement various type of music well, I think many listeners might find them almost irresistible. The IERM, on the other hand, are for listeners who like their music, “straight, no chaser,” meaning their primary goal is to know exactly how the original recording sounds—preferably with as little embellishment on the monitor’s part as possible.

BOTTOM LINE:

For those who favor monitors that add a judicious touch of mid-bass and upper midrange/lower treble emphasis, touches that add a quality of warmth and vibrancy to the music, the T2 Classic could be just what the doctor ordered. Add to this exceptional earpiece construction featuring ultra-comfy (and ultra-quiet) “40 Shore Silicone” material and you’ve got a top-tier contender at an unexpectedly reasonable price (though the firm’s new T2 Live! models will certainly bear watching and listening).

We regard the ACS Custom earpieces, in particular, as standard setters in terms of comfort, security of fit, and overall noise isolation.

SPECS & PRICING

ACS Custom T2 Classic Custom-Fit In-Ear Monitor
Accessories: Leather-like semi-hard shell road case, leather-like carry pouch, tube of comfort cream to facilitate ease of insertion, cleaning tool/wax pick, and 3.5mm to •-inch phone plug adapter.
Driver Complement: Two balanced armature drivers per earpiece.
Earpiece Construction: A “full Concha” design made from “40 Shore Silicone” (a cold cure, soft gel silicone-type material) with “SteriTouch” coating.
Cable Construction: Kevlar reinforced cable with an “anti-friction sheath,” fitted with a gold-plated 3.5mm mini-jack.
Frequency response: 16 Hz – 20 kHz.
Impedance: 6.83 Ohms.
Sensitivity: Not specified.
Noise isolation: 26 dB.
Price: $799


Manufacturer
ACS Custom USA
(516) 233-2813
www.acscustom.com

ACS Custom UK
+44(0) 1295 266665
www.acscustom.com/uk/

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