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Prolog
While covering the Munich High-End show for Stereophile last year, I was hanging around outside the MOC convention center just shooting the breeze with some folks when I saw Alex Rosson, CEO of Audeze. I'd been thinking quite a bit about planar magnetic cans and how they might be improved and had a couple ideas I wanted to run by Alex.

"Hey Alex! Got a minute?"

"Sure Tyll, what's up?"

"Well, I been thinking about planar magnetic cans and some of the problems I see in the measurements. I think…

Audeze Headphone Changes Over Time
I decided to dig into the many headphone measurement spreadsheets I've acquired over the last three years since starting InnerFidelity and compare the numerous models tested. A couple of things to note: Some of the traces for early models of the LCD-3 are an average of three or four headphones; the FR traces of these models will be somewhat less noisy in the treble due to the averaging of multiple cans response. Also, please remember that headphone measurements are notoriously difficult, and while I try to be very careful the data is not 100%…

Measurements

Having spent quite a bit of time in the article talking about the frequency response of these cans I'll not repeat myself here except to say that in the uncompensated response the reduction in energy between roughly 3kHz and 10kHz is easily seen. It is this dip that I think needs some filling in to be neutral in the upper mid-range to treble transition.

V-Moda XS ($212)
Val Kolton, CEO of V-Moda, is a funny guy. Totally committed to style and fashion, totally committed to high build quality, totally committed to music and great sound, and totally committed to doing things in his own, very unusual way.

So it was with no significant surprise when the diminutive V-Moda XS's reviewer kit arrived in a rather large box. "I wonder what he's up to this time?" I slice open the box and pulled out a large plastic bin covered in gaudy bumper stickers and filled with cheap plastic…

Sound Quality
I was a bit worried when I heard the tuning of the XS was changed from the M-80—I liked that headphone quite a bit. It deserved its place on the "Wall of Fame". Fortunately the folks at V-Moda seem to have a nuanced hand and, like with a lot of things about this new headphone, they've done a very good job of making some subtle but beneficial improvements without any other unintended negative consequences.

Overall tonal balance of the V-Moda XS is a treat. Matching fairly closely the Harman target response curve, the XS is slightly warm and quite smooth…

Measurements

Raw frequency plots are astonishingly similar to the Harman Response curve. Looking at the compensated plot you can see a fairly good resemblance of a flat but warm tilted response. The XS sounded really balanced to me—other than the loose bass and lithpy articulation in the treble. I'm thinking what we want to see in a headphone's compensated response plot, is a straight line with a -15dB tilt, 20Hz to 20kHz. It might be that if I mix my head's ID HRTF with a -15dB tilt....well, I think you can see…

Oppo Digital PM-1 ($1099)
It's a pretty bold maneuver introducing your first headphone in the rarified $1000+ category. You better have something up your sleeve. In this case it's Igor Levitsky, a long-time independent designer who has worked with BG Radia and SLS Audio on planar driver designs, who has been working on the new PM-1 driver and headphone for the past 2 years. I've been very fortunate to have had the pleasure of some long email exchanges with Igor—his enthusiasm for audio is infectious, and his understanding of…

PM-1 Planar Magnetic Driver Description
Having had the opportunity to have numerous email exchanges with Igor Levitsky, I'll be including some of his thoughts as I work through the description and justifications for this driver design.

One of the first things the observant headphone enthusiast will notice about the PM-1 is that, while it is a planar design, the sound radiating from the diaphragm surface does not go directly to the ear, but rather has to travel through a "mandarin" segmented hole prior to getting to the ear. This has raised quite a few eyebrows among…

Measurements

Charts for the PM-1 with both velour and leather pads are shown above. Aside from the slightly less reliable seal of the leather pads (as seen in the variations in the raw FR plot) and the very slightly brighter sound of the leather pads (as seen in the slightly raised leading edge of the 300Hz square wave) the two sets of measurements are quite similar and I'll adress the measurements as a whole.

Again, raw FR plots show…

Having recently announced my electrostatic headphone measurement program and the forum thread for readers to submit headphones for measurement, I've begun to see headphones arriving for measurement and the first SR-207 was measured last week. It's a good start and I look forward to filling up the headphone measurement page with all the Stax and other electrostatic headphone maker's products as time goes on.

What I didn't expect—at all—was to find myself measuring a DIY electrostatic headphone. These are not simple to build…