A very big THANKS to Audio Technica Singapore for lending me the whole 6 models of the relatively new Audio Technica Professional In-Ear Monitors, the IM series!
(FYI, I’m not working for Audio Technica, or their affiliate.)
I have around more than 2 weeks with these excellent sounding IEMs. Every day I try a model for the whole day. I used them during daily commute, in office, at home, and with different players, DACs, and amplifiers. Basically I'm quite impressed with the new IM series. With the right player / amp, none of them have any annoying frequency irregularities problem. I consider all of them, even with their own unique sound characteristic, more or less sound fairly neutral. Meaning, frequency responses are generally smooth. Some lean toward detail and clarity, some toward smooth and organic sound. Some emphasize on detail & clarity, some smooth & natural, and some are rather bass heavy. Still, their tonal balance can be considered fairly neutral. It’s simply awesome to have 6 IEMs with different variations of natural & rich sound signatures!
The Audio Technica IM series in this review:
ATH-IM01 : Single Balanced Armature driver IEM (47 ohms)
ATH-IM02 : Dual Balanced Armature driver IEM (36 ohms)
ATH-IM03 : Triple Balanced Armature driver IEM (34 ohms)
ATH-IM04 : Quad Balanced Armature driver IEM (14 ohms)
ATH-IM50 : Dual Symphonic 8.8 mm dynamic driver IEM (10 ohms)
ATH-IM70 : Dual Symphonic 8.8 mm dynamic driver IEM (10 ohms)
I received demo sets, without box and accessories, and came only with the medium size of silicon tips. The retail package will come with S, M, L silicon tips, and a pair of medium size Comply tips. The cable is detachable, 1.2 meters Y cable, with memory wire on the earphone ends. I find the new IM connector for connection to the earphone is very good. It clicks and locks the cable very well, and it seems durable. The connector shaped with polarity orientation, so no chance for cable to be plugged with reverse polarity.
I have no issue with comfort, I found they are all very comfortable on my ears after some adjustment of the memory wire. Good fit, and I could wear them for hours without getting fatigue. But we all have different size and shape of ears, so YMMV.
I found that the BA driver IEMs require proper pairing with the headphone amplifier / player for optimum sound, more than the dynamic drivers. The dynamic drivers IM50 & IM70 in general are easier to drive. Some of the BA IEMs affected quite significantly with the output impedance of the headphone amplifier (including player's build-in headphone amp). Some BA IEM get veiled and muddy with the increase of amp's output impedance, some get brighter in the treble, and some get their optimum performance at certain output impedance. That's might be one of the reason we sometime hear very different opinions of the same product. Different pairings different sound. Although there are many other factors that contribute to the sound quality, in this review I found that amp's output impedance is one factor that's worth to be observed. It will be elaborated more in this review.
The following players, DACs, & Amplifiers are the most used equipment in this review. Thanks to my friend Ong Wee Liang for lending me his Astell&Kern AK100!
The output impedance value is indicated in the bracket.
Violectric HPA-V200 (0.06 ohm)
Fiio E12DIY (0.19 ohm)
Yulong DA8 headphone output (0.26 ohm)
Audioquest Dragonfly v1.0c (0.40 ohm)
Fiio X3 (0.46 ohm)
iPod Classic 6th Gen 80GB (4.69 ohm)
Centrance DACport (9.78 ohm)
Astell&Kern AK100 (21.57 ohm)
Hifimediy UAE23 (203.26 ohm)
Except for Violectric HPA-V200, which output impedance value is taken from the Violectric website, the rest are results of my own measurement. I don't have lab grade instrument, only a simple digital Oscilloscope, Velleman PCSU200. So don't expect lab grade accuracy. The measurement results are only to be used as estimation of the amp's output impedance.
From here, I will use 'Out Z' for amplifier output impedance, to shorten it.
I noted on the following articles:
That Dragonfly indicated to have 12 ohms Out Z on the first article, and 0.65 ohms Out Z on the second article. Mine bought last Dec 2013 from Amazon ($ 99), version is v1.0c, after multiple measurement on my Dragonfly, the result consistently less than 0.5 ohm Out Z, 0.40 ohms to be exact.
Unfortunately my order for the Geek Out DAC has not been delivered during the review, so I cannot test Geek Out DAC with the IM series.
For the DACs, I used Foobar v1.3.1 on Windows 7 as the player, with WASAPI driver (WASAPI event).
Let's jump to the summary. For those who have time to read more, more in-depth review is available on the 2nd post after the summary & recommendations.
ATH-IM01, ATH-IM02, & ATH-IM03, are natural sounding IEMs with very good clarity & transparency, leaning more toward the analytical sound signature, when compared with the rest. IM02 is the most analytical, but in a good way, and also the most realistic & spacious sounding, that with proper pairing, sounds way beyond its price point. I vote IM02 as the best value among the three.
IM01 & IM03 are less analytical than IM02. And though still have a very good level of detail; they are more forgiving to recording & amps pairing. I vote for IM03 for being the most musical sounding between the 3 models. IM03 has a very good balance of detail, transparency, and smoothness, while offering the most natural tonal balance.
ATH-IM04 offers natural tonal balance & good bass in a different way: smoother, warmer, and very intimate. It seems enough to have 3 models within the variety of clean & transparent sound signature, IM04 took a different approach. While still offering good and smooth frequency coverage from bass to treble, IM04 sounds much warmer, very intimate on vocal, but less detailed & spacious than IM02 & IM03. I think vocal is what IM04 is good at.
IM01, IM02, IM03, & IM04 generally have good & rich sounding bass, but the bass level is on the natural level, not the level for bass head.
ATH-IM50 & ATH-IM70 have excellent, big and powerful bass, with very beautiful vocal sound. Bass head & vocal lovers should try these models. Tonal balance is pretty close between the two, rather bass heavy but overall tonal balance still sounds natural and in good balance. They have pretty good clarity too, no muddy midrange like I use to hear with other bass heavy IEMs. Both have smooth & organic sound signature, with very good & realistic dynamic. Vocal is very beautiful on IM50 & IM70, full bodied, nice balance between warmness & smoothness, with good clarity and silky smooth treble that extends pretty high. Although clarity is good, IM50 & IM70 are not as airy & transparent as the IM02 & IM03, and they are not the analytical type.
FYI, I use the term ‘organic’ to describe the opposite of analytical sound.
In a very simplified analogy, IM50 = IM70 + subwoofer. Bass sounds bigger on IM50, also slightly more boomy. IM50 bass level is almost on my maximum tolerable bass that is still enjoyable. More than IM50 bass level, the tonal balance will be started to get out of balance, and the bass would be too dominant. IM70 bass is tighter, with better overall clarity. IMHO It is not about which one is better, both are excellent in its own way.
Other good news is, there are similarities of IM50 & IM70 sound signatures with their bigger brother, the famous full size headphones, ATH-M50! Meaning, those who like the sound signature of ATH-M50, most probably will love the sound signature of IM50 & IM70. It seems that Audio Technica has managed to pack most of the goodness of ATH-M50 in a much smaller package!
I predict IM50 and IM70 will be as famous as the ATH-M50. Well, let’s see
Kudos to Audio Technica for offering these giant killers in this price range!
Comparison with Ultimate Ears TripleFi 10
Let me try to compare the BA IEMs with the famous Ultimate Ears TripleFi 10.
Generally all the BA IEMs in the IM series have rather more natural tonal balance than TF10. TF10 IMHO is a bit colored, especially on the mids. TF10 sounds smooth and warm, but the mids sometime lacking of clarity for classical music, especially with high output impedance such as AK100. From experience, TF10 sounds best with low output impedance, such as with Dragonfly & Fiio X3. As for smoothness, warmness, detail, and transparency, TF10 is about in between IM03 and IM04. When all paired with matching amplifier, generally, IM03 is more detailed & transparent than TF10, and TF10 is more detailed & transparent than IM04. But also depends a lot on player and amplifier. With AK100 for example, TF10 sounds too warm for my taste. I prefer TF10 to be paired with Dragonfly.
Comfort wise, the IM series is more comfortable for me compared to TF10. The cable of the IM series is also more flexible and doesn't have the coiling memory effect like TF10 cable.
IM01 on AK100 sounds a tad more open than TF10, not much. TF10 has better frequency extension, better bass, and treble extension. But sometime for classical music IM01 may sounds rather more natural in tonal balance, and slightly better imaging.
IM02 has slightly more emphasized on the mids and treble, sounds more open & transparent (although sometime may sounds a bit harsh), TF10 sounds smoother and slightly warmer. Bass level and impact is about the same. IM02 is more revealing, TF10 sounds smoother and more forgiving. For vocal generally TF10 sounds better than IM02, smoother and warmer. But for good audiophile recording of acoustic instrumental and classical that sound best with more transparency and spaciousness, IM02 is better, sounds more open, transparent, with more focus and spacious imaging.
IM03 (on DACport) has better and fuller bass than TF10, and a more even frequency response from bass to treble, more homogeneous sound signature throughout the spectrum, while TF10 treble sometime sounds a bit on a different color and can be a bit detached from the mids. IM03 sounds more open and transparent than TF10. IM03 mids a bit more laid back in presentation than TF10 mids, but more open sounding. Overall IM03 sounds more natural than TF10, especially for classical music, where IM03 has better detail and transparency. Generally I prefer IM03 over TF10.
IM04 is slightly warmer than TF10, so for vocal TF10 is slightly more transparent than IM04.
Comparison with JVC HA-FXD80, Yamaha EPH-100, TDK IE800, & vSonic GR07 Bass Edition
For the dynamic drivers, let me simplified this comparison by listing what I like most to what I like less, top to bottom:
ATH-IM50, ATH-IM70, & JVC HA-FXD80
Yamaha EPH-100 & TDK IE800
vSonic GR07 Bass Edition
IM50 & IM70 sound signatures are different than the ‘Natural V-Shape’ sound signature of JVC HA-FXD80. All of them have excellent bass & dynamic. IM50 & IM70 IMHO are a better all-rounder, more natural tonal balance, and sound much better on vocal. I like the JVC HA-FXD80 better, for Classical, acoustic instrumental, and other recordings that sound best with airy & sparkling treble. JVC HA-FXD80 also slightly better on imaging, with wider imaging. But IM50 & IM70 imaging are also pretty good, and don’t sound congested. I like the three equally; they are good in their own ways.
Yamaha EPH-100 has closer sound signature to IM50 & IM70 than the others, but IM50 & IM70 have better bass and treble extension than EPH-100. While TDK IE800, another IEM with dual drivers that work in different fashion than the Dual Symphonic drivers of IM50 & IM70, doesn’t have the full sounding and tight bass of the IM50 & IM70. IE800 sounds clearer and more airy, and could be nicer for classical orchestra, but it doesn’t have dynamic as good as the IM50 & IM70.
vSonic GR07 Bass Edition sound signature maybe closer to TDK IE800 than others. But if I have to choose between the two, I prefer the TDK IE800 for smoother treble, and better overall tonal balance. But they are pretty close.
Recommendation on Recordings:
Audiophile & Classical recordings, recorded with natural tonal balance and natural stereo imaging as the goal, and best enjoyed with spacious sounding earphones, IMHO the BA IEMs: IM01, IM02, & IM03, are the better choice. They sound very natural, with excellent detail, transparency, spacious, focused & realistic imaging. For my classical collections & binaural recordings, IM02 & IM03 are my favorite.
Modern music that mostly recorded with closed miked approach, pop, vocal recording, and electronic music that best enjoyed with realistic level of bass, smooth, rather warm, & intimate midrange, the IM04, IM50, & IM70 are the better choice.
IM04 sounds quite different than IM50 & IM70, with flatter and more natural tonal balance. While IM70 has bigger bass than IM04, IM50 has even bigger bass. For house music, it is best with IM50 with its big and full sounding bass. As for my Stockfisch albums & other closed miked vocal recordings, they sound best with IM50 & IM70.
The sound signatures of IM50 & IM70 may seem to be more appropriate for modern genres. But they actually have good enough clarity and detail for classical music as well. After listening my favourite classical albums with IM50 & IM70, I found they are pretty enjoyable for classical as well.
Recommendation on Players and Headphone Amplifiers:
Although we can start with the general recommendation of the matching value of output impedance from the in-depth review, there are many more factors that contribute to the final sound signature, so personal audition is still the way to make the final judgement.
The BA IEMs are more affected with the value of output impedance. So if audition is not possible, it is better to choose the model that is more output impedance friendly, such as the IM03. For low power players and smartphones, that usually have medium to high output impedance, IM50 and IM70 are the safer models to choose. For example, on my smartphone, Samsung Galaxy S2, that I measured has around 50 ohms output impedance, it sounds best with IM50 & IM70. For those with better, dedicated music player, or good headphone amplifier, may consider the BA IEMs for more transparent and spacious sound.
For me, I like natural realistic type of sound signature. I like good clarity, transparency, rich treble sparkle, with spacious imaging, and not so much of a fan for warm sound signature.
Realistic level of bass is a must for me. Though I'm not a basshead, and I don't like oversized bloated boomy bass, but I want bass with proper level and strength, not anaemic bass.
From the 6 models, I really like the IM02 and IM03 clear & transparent sound signatures, while I also get addicted with IM50 and IM70 for their big, smooth & organic sound. Although I know IM04 will have its own fans, IM04 is not my cup of tea, too warm for my taste. In the end, I bought for myself the IM50, and my brother bought the IM03. IM50 is quite unique to my collection. I have mostly in my collection, clear and transparent, more analytical sounding earphones, so an earphone that sounds like having a build-in subwoofer, but still sound natural and clear, is something that I didn't have. And listening vocal recording through IM50 is highly addictive
Some Albums mostly used in this review:
Edited by earfonia - 2/14/14 at 6:56pm