Ergonomics and Fit
While fit is certainly important in full-sized, over- or on-ear headphones, it is even more critical for in-ear monitors. The T8iE comes with eight different tip options. Five are different-sized silicone tips while three are various Comply compressible foam tips. The T8iEs are lightweight and compact (especially when compared to a multi-driver balanced-armature design such as the Noble K-10) and are “anatomically shaped” with an oval molded design that rests in your ear’s auricle and puts the cabling over the ear so that light pulls or tugs won’t dislodge the phones.
The T8iEs come with two cable options. Along with a “standard” 1.3-meter cable terminated with a 3.5mm stereo plug, Astell&Kern includes a balanced cable terminated for the AK100 II, AK120 II, AK240, AK300, AK320, and AK380. This cable uses a 2.5mm 4-pole termination. Also, as you would expect from a premium offering, the T8iE comes with a nice hard leather case and a metal shirt-attachment clip. Astell&Kern also has several other cables available from Crystal and Mundorf at additional cost on its website.
I tried all the tips included with the T8iEs and settled on the largest of the Comply. My ear canals start wide and narrow quickly, like those of many other people, so I usually need to use either the largest tips for my outer canal or the smallest ones if the in-ear monitor’s design calls for a deeper insertion, such as with the Etymotic 4P monitors. The T8iEs’ design required the former because of where it sat in my ear and its fairly large diameter barrel. When properly seated the T8iE isolated me from the outside world nicely. Astell&Kern has no published isolation specifications for the T8iEs and I lack an ear coupler for measurement, but I will take a WAG (wild-a** guess) that it’s somewhere between -18 and -20dB.
I used a variety of devices with the Astell&Kern AK T8iEs during the review including the Aurender W1000 Flow, NuPrime DAC-10H, Grace m9xx, Oppo HA-1, Sony NW-ZX2, Astell&Kern AKjr, Astell&Kern AK240, Calyx M, Sony PHA-2, and Acoustic Research M2 players. In every case there was more gain in reserve than in use at my own personal maximum volume levels. Among all the in-ears currently at my disposal, the T81Es rank among the most sensitive, requiring some of the lowest gain settings I’ve used. The problem with sensitive in-ears such as the T8iE is noise and hiss from some amplifiers due to the earphone’s high sensitivity. With all the portable players I had no issues with noise or hiss, but some desktop earphone amplifiers, primarily designed to handle hard-to-drive headphones, could be problematic if they lacked adjustable gain settings. Having said that, one of the best desktop combinations was the T8iEs paired with the Grace m9xx DAC/headphone amp. There was only the slightest amount of hiss when no music was present and the midrange clarity, bass extension, and dynamic drive were all first-rate.
The T8iEs have removable/replaceable cabling that can present issues if best practices are not employed. Unfortunately, I could find nothing in the otherwise comprehensive owner’s manual describing what “best practices” for removing these cables might be. I noticed some comments in the Head-Fi T8iEs’ message section that a few owners have returned multiple sets of cables for connection issues. I suspect these problems may be at least partially due to how users are removing and reattaching the T8iE’s MMCX connectors. From what I’ve seen so far, no manufacturer who makes in-ear monitors with a removable/replaceable cable has come up with a perfect connection scheme. The problem of balancing ease of attachment with reliability and comfort has yet to be completely solved.
In theory a single-dynamic-driver design like the T8iE should be more rugged than a comparable balanced-armature design because the dynamic driver can survive more drops and other abuse without it affecting its target frequency response. For prospective owners who know they’re hard on in-ear monitors the T8iE’s robust overall design could be an important factor in its favor.