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.
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.
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.