The ATH-IM02 has been praised almost universally for being one of Audio-Technica’s most complete sounding products to date. But what has really changed?
I’m more of a whole wheat, multi-grain kind of guy, though, and I wondered about why there was so much enthusiasm surrounding the IM02. While the IM02 did indeed sound very nice, to me, it sounded very similar to the CK90PRO and CK90PRO MK2 that were introduced years ago. Yet, those older models didn’t receive nearly as much attention in four years as the IM02 got in a mere four months.
I was perplexed. After all, the ATH-IM02 actually sported technical specifications that were nearly identical to those of the ATH-CK90PRO MK2. Sure, the stated impedance of the IM02 was a single ohm count lower, and the sensitivity was a couple dB higher, but the fact of the matter was that the two earphones used the same exact driver assembly and outputted to an ‘acoustic horn‘ tube, canted at the same exact exit angle and opened to the same diameter. For all intents and purposes, from an acoustic design standpoint, these two earphones were the same.
“But they sound different! How could that be?”
Yes, the Audio-Technica ATH-IM02 features all-new ergonomic features over the older ATH-CK90PRO MK2, but retains the same driver assembly. It’s actually understandable that both the CK90PRO MK2 (and the original CK90PRO, for that matter — SONOVE’s measurements of the original ATH-CK90PRO bear close resemblance to those of the CK90PRO MK2 in impulse and impedance curve — frequency response isn’t directly comparable between different measurement apparatuses) and the IM02 share the same receiver — it’s a nice one. At the heart of both is the Knowles Electronics GQ-30783; this GQ driver has also been used in several other earphones, specifically the Westone 2, InEar StageDiver 2, Lime Ears LE2, and a few other products from China that fewer people are familiar with, such as the AudioSense AS-2.
So what accounts for the slight differences in technical specification, and the differences in subjective listening?
Well, if we take the example of the Westone 2 and InEar SD2 (see thoughts here), which both also use the GQ-30783, we’ll see that the electroacoustic measurements, as taken from InnerFidelity, are nearly identical:
Other than a minor few dB of variation here and there, the frequency response is nearly identical; the major mechanical resonance points are the same, and the other electroacoustic data, such as square wave response, impulse response, and electrical impedance/phase, are even more similar.
However, in a direct subjective audio comparison, the W2 and SD2 sound quite different from one another. The SD2 sounds tighter and more present, with more forward, less muffled vocals. The only difference between the two are an increased build quality, tighter fit rate, and isolation with the InEar SD2 — but these factors put together actually amount to a significant difference in sound quality. The difference in the plastic tubing used on the Westone 2, compared to the solid, 3D-formed acrylic in the Stage Diver 2 is actually enough to create measurable differences in frequency response and impulse. Sort of like opamps or DAC chips in a signal chain, balanced armature drivers are the same, in that even in very similar setups, small variations such as tubing material, housing stability will affect change in the most unpredictable of ways.
So let’s get back to the Audio-Technica models; I’ve compared the CK90PRO MK2 and the IM02 directly to each other — the audible difference between the CK90PRO MK2 and the IM02 is actually much smaller than the difference between the W2 and SD2! The IM02 gains a miniscule amount of added clarity and tightness over the CK90PRO MK2, along with slightly better instrumental separation. Possible reasoning for these improvements are (1) a better shielded cable (beyond ergonomic improvements such as flexibility and thickness) that allows for separate ground wires for the left and right channels all the way down to the 1/8″ plug, and (2) a large, denser, more vibration stable housing that stays more securely in the ear because of shape.
So what’s all the fuss again about the IM02 being the “gem” of the Audio-Technica IEM lineup, when they’ve had essentially the same earphone since 2010 in the ATH-CK90PRO?
Some audiophiles have come out and declared the ATH-IM02 to be the most capable IEM of the new lineup, but the fact is, Audio-Technica did not hire some new acoustical genius to design the IM02. The IM02 is merely a minor, incremental improvement over its immediate predecessors, the CK90PRO and the CK90PRO MK2 — mostly in aspects of ergonomics. Is it the best one yet? Yes. But it’s no reinvention of the wheel, and it’s certainly not a big leap in improvement.
We all like new products; they’re shiny and eye-catching, but don’t let new products and new marketing pull wool over our eyes — just because it looks new, doesn’t mean it’s actually different.
About Mr. T
Mr. T is an in-ear fanatic by day, and writes SOAP notes by night. He pities the fool who actually has the patience to read through his stuff.
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