Headphone Reviews

Stax SR-007 Late Mk. 1 (~$2600)
Description - This is a full size, open, electrostatic headphone. I'll quote one of the Stax Mafia here:

SR-007 Mk1 early version - different driver frame plus some minor material changes, older style carbon fiber box.

SR-007 Mk1 late version - the version tested here and the most common of the Mk1's, S/N either 7xxxx or SZ1-xxxx

SR-007A/SR-007Mk2 - S/N SZ2-xxxx, Stax change the earpads, how they sit and introduce a port to the earcups. Sound is a mixed bag depending on fit but can be fixed to sound pretty much like the Mk1.

SR-007A/SR-007Mk2 - S/N SZ3-xxxx, often called the Mk2.5, Stax supposedly change the diaphragm which results in a much more forward sound signature.

Pink Noise - Slightly muffled sounding. Fairly even from lowest octave to upper mids, but treble markedly shelved down with clearly audible mid-treble peak ("sss").

Bass Texture/Extension - Good texture and extension but slightly lacking in heft relative to the rest of the music.

Bass Slam - I'm quite surprised how well these do in this department. Though a tad low in level, the extension is good, so these deliver a good bit of punch. However, I do hear a bit of looseness the takes the edge off the slam.

Midrange - Wow, the mid-range is very impressive on all these headphones, and the SR-007 is no slouch. Plenty of heft and organic tonality, but the transition to the treble is a bit rough, and the last bit of realism isn't quite there. Still I'm very surprised how warm and inviting these are.

Treble - Oddly, these sound somewhat laid-back but have sparkle at the same time. Sort of the opposite problem from the LCD-2, these seem to me to lack attack in the highs; a bit too airy without treble impact. Instruments are, however, very naturally portrayed, though a bit distant.

Dynamics - I find these the least dynamic of the bunch. The somewhat laid back treble lacks snap, and they sound a bit confused on complex dynamic passages relative to the others.

Imaging - Imaging is nice and wide, and fairly specific, but somehow lacks depth compared to the 009, likely due to the relaxed highs and a somewhat veiled sound.

Measurements

Both the 007 and 009 had a small step in the frequency response at about 50Hz. This may have contributed to the slightly thinner sounding bass than the planar magnetic headphones in the test. Otherwise, the response below 2kHz is pretty good, though a bit bumpy. Other than the narrow and moderately sized peak centered at 10kHz, 2kHz to 20kHz is shelved down 10dB relative to the mids and bass, likely delivering the somewhat "veiled" or muffled sound I heard. This may be tempered just a bit by the narrow peak at 10kHz, which, it seems to me, may be adding a little sparkle to the sound.

30Hz square wave is a little bowed, but basically quite good. Frankly, I'm surprised an estat delivers this much bass.

Both the 300Hz square wave and impulse response show a fast and well behaved diaphragm, other than a little noise.

THD+noise plot is surprisingly flat indicating good power handling properties.