Companies that sell in-ear monitors seldom talk much about the technologies inside their products. But they should, because there are big differences between the ~$20 Philips and Skullcandy IEMs you buy at Target and the ~$200 models you get from Etymotic or Shure.
Usually, relatively inexpensive IEMs use dynamic drivers, which are essentially miniaturized versions of conventional speaker drivers. Like the woofers and tweeters in your home or car speakers, they have voice coils attached to diaphragms that move to make sound.
Most expensive IEMs use balanced armature drivers. A balanced armature looks much like a teeter-totter. The tiny "lever" of the teeter-totter — the armature — is wound with wire and suspended in a magnetic field. As electrical signals pass through the wire, the armature rocks up and down. One end of it is connected to a diaphragm, which moves to make sound.
Some IEMs have two, three, or more armatures. Some use hybrid technology, with a dynamic driver handling the bass and one or two armatures handling the mids and highs.
Generalizing about which technology is best is dicey because the only way to compare them directly would be to have samples of each technology tuned for the same frequency response, supplied with the same tips, etc. But manufacturers seldom tune their low-priced models the same way as their high-priced models.
However, we happened to get three models from TDK that use three different driver technologies: dynamic, single-armature, and dual-armature. So I thought it’d be fun to run them past our headphone listening panel — without telling them what technologies they were hearing or what the prices were — to see what they thought.
You can see from the accompanying photos that these are three very different earphones. The EB950 is the most conventional; it doesn’t look much different from most other dynamic IEMs. The BA100 is a comparatively long device, designed to fit deeper into your ear while also sticking out further than normal. The BA200 employs the over-the-ear cable routing seen in IEMs from such companies as Phonak and Shure.
Our panelists — S+V contributing tech editor Geoff Morrison, and L.A. voice actress Lauren Dragan, L.A. jazz musician Will Huff, and I — compared the TDK models using a Rane HC 6S six-output professional headphone amp, with a Denon DVD-2900 DVD/SACD/CD player or our smartphones or MP3 players as source devices. Although we used the Rane amp to make quick comparisons easy, all of these earphones can be driven effectively by pretty much anything with a headphone jack, including phones, computers, and other portable devices.
I’d assumed that the panelists would be impressed with the bass power of the EB950 dynamic, more impressed with the mids and highs of the BA100 single-armature model, and even more impressed with the mids and highs of the dual-armature BA200. But I was wrong.
Over and over, the most enthusiastic comments I heard concerned the BA100. “It looks weird but fits surprisingly well,” Geoff said, later calling the BA100 “the best of the bunch.” Lauren was even more enthusiastic. “This is the best in-ear headphone I’ve tried in all my Sound+Vision tests,” she raved. “There’s a decent amount of bass, and you can hear the distinct pitches of the bass notes. The mids and treble are clean and accurate.” Will also remarked that he liked the BA100’s accurate midrange, although he preferred the EB950 for its weightier bass.
I got to spend the most time with the BA100s, and came away with a favorable impression of the sound—but was also disappointed that TDK didn’t put more thought into the industrial design. The earpieces hang pretty far out of your ears, and the cables are attached at the ends of the earpieces, so a slight, accidental tug on the cables can easily dislodge the earpiece. I also had fit issues. Even though I have the largest ear canals of all the panelists, I can almost always find a medium or large tip that fits me. Yet none of the silicon tips TDK provided was large enough to give me a good fit. The Comply foam tips gave me an adequate, although still imperfect, seal.
Still, the BA100 sounded great to me. The mids and treble are spectacular, with loads of detail and such a smooth, natural sound that even Vince Neil’s vocals on Mötley Crüe’s “Kickstart My Heart” didn’t sound grating as they almost always do with other headphones. The treble, in particular, sounded smoother than that of the $119 Phonak Audéo PFE 012 single balanced armature earphone I recently tested, although the PFE 012’s fit and ergonomics far outshine those of the BA100.
Probably partly because of the mediocre seal I got and partly because of the BA100’s bass-shy balance, I never got a satisfying bottom end out of this model, but the bass I did get was smooth, even, and precise. To me, the BA100 sounded like a great minimonitor instead of like a great tower speaker.
Next in our panelists’ assessment — and remember, they didn’t know anything about the earphones they were listening to except that they were all TDKs — was the EB950. Will liked it a lot: “It’s like being hit with a 10-foot wave of sound,” he enthused as he listened to Linda Ronstadt’s Round Midnight CD, complementing the EB950’s potent bass response and enveloping ambience. But Lauren and Geoff thought the tonal balance too bass-heavy. “It’s muddy and thuddy,” Lauren said.
My extended audition of the EB950 left me with the opinion that the bass sounded punchy, with somewhat exaggerated dynamics, but that it wasn’t grossly out of proportion with the mids and treble. To me, it sounded like a home theater system with a really good subwoofer that was turned up about +3 dB too loud for my taste. The midrange and treble sounded competent enough, but never compelling. In my opinion, the sound seemed pretty typical for a midpriced dynamic earphone. In a comparison with the $99 SOL Republic Amps HD, the EB950 wasn’t embarrassed, and in fact it had a little more zip and excitement in the upper treble. Yet the Amps HD always sounded more natural and involving.
The BA200 got the least amount of love from the panel. Geoff and I both noticed problems in the upper midrange and lower treble. “It has better detail than the other two, but too much sibilance,” he said when he was listening to singer Radka Toneff’s recording of “The Moon’s a Harsh Mistress” from her Fairytales CD. To me, the BA200 sounded as if the midrange response was uneven, accentuating certain frequencies in a way that, yes, increased the sibilance and also robbed voices of that gorgeously natural sound I heard with the BA100. I have to wonder if the BA200’s somewhat rough midrange results from the crossover between the two balanced armature drivers.
Lauren found the BA200’s bass rather feeble and poorly defined, although she and I both preferred the BA200’s fit to the BA100’s. Will’s comments converged with mine: I noted an “overall lack of energy” while Will said, with perhaps a trace of puzzlement, “It lacks everything.”
Brent Butterworth and Geoff Morrison combine their years of gear testing and knowledge in one überblog of irreverence and techiness.
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