The SR007, or “Omega 2”, was Stax’s flagship between 1998 and 2011. The Mk1 version had a few revisions, this one being an early model (serial number in the 71xxx range) with gold cups and brown headband/earpads. It’s a very beautiful pair of headphones, and quite comfortable.
It looks big on pictures but is not that large in reality, and relatively light. The SR-007 is hard to power and most Stax amps don’t deliver enough current to power it, which affects the dynamics/compression and the bass/treble. The Stax Sigma I had was however harder to drive. The SR-007 is a warm headphone and would sound too soft with weak amplifiers.
○ Release : 1998
○ Current status : Discontinued
○ Type : Over-ear / Open-back
○ Measured weight : 371g
○ Impedance : 170k Ohms
○ Sensitivity : 100dB/100V
○ Average used price : $1200-1700
The SR007 mk1 is very warm. It sounds close to the Audze house sound and rumors say Audeze based their tonal signature on the 007. Bass is a bit elevated (around 2-3dB) and has good quantity, with very nice extension – a bit better than HD800, but not as good as an Hifiman HE-6 or Audeze LCD-4. Next to a good dynamic or planar, it lacks some physical slam despite the good quantity. Bass is a bit “fat” and thick, and it can be worse with weak amplification.
Midrange is lush, very refined and pleasant. It’s mostly dipped around 2-3 khz but vocals dont sound distant or recessed. I prefer by a mile the 007 midrange to the HD800. Extremely liquid and organic sounding. The detail and resolution of the midrange is amazing.
Treble is very smooth but not very coherent. Low-treble is very recessed, but there is a 10khz peak that sticks out a lot, and a lot of upper-treble. No “shh” or edgy harshness (good!), but a lot of air and sparkle, without coherent and good treble energy/body. As a result, treble, while being clean and extremely refined, sounds a bit thin.
Staging is decent, with good depth, but not better than HD800, K701 or L700. This is a fast sounding headphone, but it can sound compressed at times. I tried it on my 323s and on a KGST, and the Mjolnir amp could provide a boost in macro-dynamics and bass control. I hope to try a modern SR-007 (mk2.9) as it is said to be a bit more forward in the midrange/treble.
Measurements & Resources
Bass lift around 55hz, but the extension remains flat below the 50hz drop. Major recession around 2-7khz, a few dBs below what would be the ideal for me. Sticking out peak around 9khz, easily audible. There’s a solid amount of air, just like on most Stax.
The overall frequency response is close to the typical signature of the Audeze LCD serie models : flat bass and low-mids, and recessed upper-mids / treble.