I’ve always been fascinated with the technology behind electrostatic headphones, but never found the extra cash lying around to pick up a set. Fortunately for me, I’m good friends with Head-Fi member Spekkio, who just so happens to be a bit of a Stax addict. I’ve known him to be quite picky with his audio equipment, witnessing several purchases over the years followed by quick resales after. He’s held on to this particular pair of Stax headphones for quite a while though, which is quite a feat considering his purchasing history.
For the benefit of those who have no idea what electrostatic headphones are, allow me to give you a brief description on how it works. They work by harnessing the electrostatic force to modulate or flex a diaphragm, in contrast, conventional headphones apply electromagnetic force. A thin piece of mylar is used as a diaphragm, encased within 2 conductive sheets of metal called “stators”. They trap and charge the air, creating a pressure that pushes the mylar in both directions. This form of sound creation requires a large amount of electricity, which is why a specific kind of amplifier has to be used with these headphones. Due to the large voltage required, the electrostatic amplifiers require a wall plug, coupled with the fact the headphones are open and aural by nature, these are not portables.
Before I could take a gander at his revered pair of headphones, he pulled out something interesting which I’ll quickly describe now. Its a pair of Stax SR-003 open air type in-ear speakers. In short, it’s much like a “Baby Stax” so to speak. It functions on the same princples as full size electrostatic headphones, just on a miniscule version. It has a short canal stem wrapped in silicon that’s supposed to sit in your ear canal which ordinarily should isolate sound, but since it’s an open air type, it doesn’t isolate sound and the in ear design is to increase listening comfort. I was rather bemused putting these on, it may have been designed to add comfort, but I didn’t think it was comfortable at all. It felt slightly more intrusive than an on-ear bud and it doesn’t sit or fit like an in-ear monitor should. I listened to it on a Stax SRM-252S electrostatic amp that looks just as novel as this gimmicky “Baby Stax”, it too was ridiculously small for an electrostatic amp. The amp was connected to a JDS Lab ODAC, with lossless quality files pumping through it. After a couple of songs, I had to take them off, not from the discomfort, but I didn’t think they sound great at all. Sound stage seemed unimpressive, bass was diminished, simply put, it was a lot like standard fare from sub $150 in-ear monitors. Cute idea but completely unnecessary.
Next, we moved on to his prized pair. The Stax SR-007 Omega II Mark 1. Production of these stopped in 2007 when the Mark 2 was released. The Mark 2 didn’t retain the bass nor treble of the Mark 1, neither did any of the Stax models that came after. As such, many would consider the SR-007 Omega II Mark 1 the “bassiest” of the lot. Since the end of its production, it’s become a much sought after model in the second hand market. To illustrate this point, a quick search on eBay and you’ll find a 5 year old pair going for $2,198. The omega range started when Stax changed the design of their electrostatics from a rectangular design to a circular look. The SR-007 Omega II Mark 1 doesn’t have removable cables, and features lambskin leather detailing. They were extremely comfortable, although it took a little bit of getting used to the pressure build up in your ear. We paired the SR-007 Omega II Mark 1 (let’s call it the MK 1 from now on) with the Stax SRM-323S electrostatic amp, with the JDS Lab ODAC as our source.
My reference equipment were the Grado project, with UP-OCC copper dual mono to Hirose balanced connector cable, fed through an iBasso PB1 balanced amplifier, out through a UP-OCC copper line out dock to an iPod Classic. We’ve been meaning to compare the 2 set ups for a while now, and we’re very glad we did. The files used were of course lossless and identical despite 2 separate setups being used.
We took turns listening to each selected song, and compared our thoughts after every song, coming to a unified conclusion every time. We started with some Guns N’ Roses, tracks like Welcome to the Jungle and Sweet Child O’ Mine. The MK 1 astounded me with it’s sub bass, it charged the tracks with a phenomenal rumble that was very enjoyable. However, there was a lack in mid bass that made the tracks less exciting as well, the bass “slam” wasn’t apparent. Instrument separation was stellar, giving me an acoustic 3D representation of the band and it’s instruments very clearly. Sound stage was deep and convincing. Treble was much like the bass, enjoyable but lacked excitement or “sparkle”. In contrast, the Grado seemed to have plenty of hard hitting bass, but not much sub bass. Treble extension was better and presented a very lively presentation. Instrument separation was comparable but slightly worse than the MK 1, but sound stage was about the same. During guitar riffs though, we both preferred how they sound through the Grado over the MK 1. Every chord was so pronounced, it sounded like a live performance.
Next we tried folk band Mumford and Sons. Little Lion Man was a song we were both very fond of. Once again, the MK 1 showed off it’s speed in handling complex soundscapes. Every instrument seemed like it was in a sphere of their own. Vocals were clear and well presented. However, the decision between the MK 1 and the Grado on this one was difficult to say the least. Simply put, we liked them both and called it a draw.
Scouring through our lists of songs, we came across U2. I picked Walk On, which is probably one of the most popular songs by the band. Here, I have to to say, the MK 1 edged out the Grado a tiny bit. The vocals seemed clearer and slightly better presented as compared to the Grado. The sub bass on this track was what it needed as well, which the Grado lacked in quantity. Spekkio thought they were about the same, but I think I’ll give this one to his MK1.
We might have played a few more songs, but I doubt there would be any point describing similar findings. Sound quality and presentation wise, these 2 set ups are on par. Yes you read that right. They’re both excellent performers and we have yet to find anything else better that doesn’t sacrifice something crucial to the listening experience. My Grados give a very realistic live performance experience and his MK 1 gives a quality studio recording experience. 2 very different flavors but both equally enjoyable. Now to highlight the difference between the MK1 and the other Stax models, Spekkio recently visited Japan and had a go at a few of the other Stax models including the SR-009. He didn’t like what he heard, according to him, on some models, mid bass was increased, and treble increased, but sub bass was vastly diminished. The overall presentation, including that of the SR-007A, wasn’t as enjoyable to him as his SR-007 MK 1. I trust his opinion, and would pick up a MK 1 should I ever feel like venturing into the electrostatic world, it had just the right balance in my opinion. With that, I leave you to one final picture. My Grados on par with the legendary SR-007 Omega II Mark 1, would you believe it?