When the Stax SR-009 first came out, there wasn't anything on the market really capable of matching its resolution and clarity. Give or take 7 years later, there still isn't really anything on the market that can match the detailed, transparent sonic image only electrostats can provide
In terms of positives, the SR-009 are still the most transparent headphones on the market. I've always hated phrases that describe transparency, "it sounds like an open window to the music" or "just the music" due to their vagueness. Whenever reading comments such as those on the SR-009 I always wondered what it was that my headphones weren't doing right. Was it the sound signature that was limiting my open window? Maybe my headphones lack of transient speed? The goal of ultimate transparency is to have the listener forget that he/she is wearing headphones, I personally believe that the only real way to understand transparency is to hear it, and believe it or not, it's not exactly what everyone goes for. Transparency implies an ultra-revealing, and natural sonic image, and thus can be tiring. Constantly having an ultra low distortion microscopic view into your music can wear you out. Every headphone seems to have a flavor except for the SR-009. It offers perfection in speed, transients, decay, resolution and realism, but lacks flavor and coloration.
Just about every headphone I've been through, I've always found flaws in its sonic signature that lacked the "technical" 5% to give a 100% ideal musical experience. Even the HD800 (with SDR modifications) I found to be somewhat lacking in ultimate speed, and only now owning the SR-009s, transparency have I realized this. Electrostats are on another plane of sonic existence compared to everything, they have it and everything else doesn't really have it (yet). The SR-009s have the speed to resolve just about anything the song offers due to their ultra-fine film diaphragm. However it seems that these ultra fine diaphragms have their fair share of weaknesses
Mainly Dynamics...
Head splitting, ear shattering, and explosive aren't the kind of phrases you'd use to describe the SR-009. It's sound is more like clean, fast, and effortless, yet that sound is somewhat physically 2-dimensional. They lack the ability of headphones such as the Utopia to reach out and tickle your ears. To burst out of the mold the diaphragm provides. which leads me to ask...
Where's the meat?
The sound of the SR-009 is like eating the most delicious meal in the world, but not having it fill you. The SR-009 lacks that filling euphoria that you get when you bite into a thick steak (e.g. Focal Utopia, Audeze anything). There's a whole meal after the meal, namely when your sitting on your couch after dinner recuperating and watching Sunday night football that the SR-009s seem to lack, it leaves you hungry. I'm not saying that they're thin or un-involving, their tonal balance prevents that, however compared to today's offerings, the SR-009 lack big boy dynamics, which seems to be a common characteristic in these new gen thin film diaphragms (Hifiman HE-1000). While the HE-1000 is just polite and smooth, the SR-009 is a straight edge of a headphone that still remains sonically involving due to it's sheer resolving capabilities.
Now onto Sound
Signature
Basically perfect, the SR-009 has the most linear SS I've ever heard, especially the treble. The massive dip at 6k is perfect, prevent harshness and sibilance (which plagued the HD800). It naturally resolving quality leave no vagueness in the treble either. The bass is extremely linear as well (just look at the graphs, it's like fiction). It's an extremely clean sounding bass that reaches very low, though not as low as Audese's offerings, but they go toe to toe with any other dynamic headphone. Bass resolution is also ungodly impressive. The SR-009 are like the CIA's version of Photoshop, where they can zoom into anything and maintain resolution.
SoundStaging and Imaging
Here's where they lose to the other World's best headphone. The HD800's bests them in soundstage width, and overall imaging. The HD800s are the closest thing to speakers, whereas the SR-009s are still blatantly headphones (which is fine, it's why you still listen to headphones). The sound is still in your head with the SR-009. The imaging of the SR-009 however is very impressive due to its speed, though not as much as the HD800s, which have that extra bit of space allowing more precise placements of various sounds. However, I do feel like the SR-009s do a better job in the sizing of the instruments and tones. I felt that the HD800s made tone and instruments larger then they actually were, whereas the SR-009 has more accurate sizing (not placement though). The Utopia's also do a good job of this, and are actually better then the SR-009s at this.
My Equipment and Biases
I run the SR-009s through a KGST, but have heard them through the Blue Hawaii, and various other DIY efforts. Now you can criticize me (and my 5k setup) for not having the last word in amping the SR-009s, but I highly doubt that they would ever have better dynamics then the Utopia, the Audeze's, or even the HD800 (which did actually have greater slam) on a well driven amp. The SR-009 was never design to have amazing slam or powerful dynamics, and while it has good dynamics, they just can't match traditional dynamic headphones in this category. It was never a focus to begin with, and that quality is very apparent when listening to the SR-009s
Conclusion
It all depends on what your looking for. If you want the clearest window into music, estats my friend, but you must be willing to trade the dynamics and low end slam for it.
In terms of positives, the SR-009 are still the most transparent headphones on the market. I've always hated phrases that describe transparency, "it sounds like an open window to the music" or "just the music" due to their vagueness. Whenever reading comments such as those on the SR-009 I always wondered what it was that my headphones weren't doing right. Was it the sound signature that was limiting my open window? Maybe my headphones lack of transient speed? The goal of ultimate transparency is to have the listener forget that he/she is wearing headphones, I personally believe that the only real way to understand transparency is to hear it, and believe it or not, it's not exactly what everyone goes for. Transparency implies an ultra-revealing, and natural sonic image, and thus can be tiring. Constantly having an ultra low distortion microscopic view into your music can wear you out. Every headphone seems to have a flavor except for the SR-009. It offers perfection in speed, transients, decay, resolution and realism, but lacks flavor and coloration.
Just about every headphone I've been through, I've always found flaws in its sonic signature that lacked the "technical" 5% to give a 100% ideal musical experience. Even the HD800 (with SDR modifications) I found to be somewhat lacking in ultimate speed, and only now owning the SR-009s, transparency have I realized this. Electrostats are on another plane of sonic existence compared to everything, they have it and everything else doesn't really have it (yet). The SR-009s have the speed to resolve just about anything the song offers due to their ultra-fine film diaphragm. However it seems that these ultra fine diaphragms have their fair share of weaknesses
Mainly Dynamics...
Head splitting, ear shattering, and explosive aren't the kind of phrases you'd use to describe the SR-009. It's sound is more like clean, fast, and effortless, yet that sound is somewhat physically 2-dimensional. They lack the ability of headphones such as the Utopia to reach out and tickle your ears. To burst out of the mold the diaphragm provides. which leads me to ask...
Where's the meat?
The sound of the SR-009 is like eating the most delicious meal in the world, but not having it fill you. The SR-009 lacks that filling euphoria that you get when you bite into a thick steak (e.g. Focal Utopia, Audeze anything). There's a whole meal after the meal, namely when your sitting on your couch after dinner recuperating and watching Sunday night football that the SR-009s seem to lack, it leaves you hungry. I'm not saying that they're thin or un-involving, their tonal balance prevents that, however compared to today's offerings, the SR-009 lack big boy dynamics, which seems to be a common characteristic in these new gen thin film diaphragms (Hifiman HE-1000). While the HE-1000 is just polite and smooth, the SR-009 is a straight edge of a headphone that still remains sonically involving due to it's sheer resolving capabilities.
Now onto Sound
Signature
Basically perfect, the SR-009 has the most linear SS I've ever heard, especially the treble. The massive dip at 6k is perfect, prevent harshness and sibilance (which plagued the HD800). It naturally resolving quality leave no vagueness in the treble either. The bass is extremely linear as well (just look at the graphs, it's like fiction). It's an extremely clean sounding bass that reaches very low, though not as low as Audese's offerings, but they go toe to toe with any other dynamic headphone. Bass resolution is also ungodly impressive. The SR-009 are like the CIA's version of Photoshop, where they can zoom into anything and maintain resolution.
SoundStaging and Imaging
Here's where they lose to the other World's best headphone. The HD800's bests them in soundstage width, and overall imaging. The HD800s are the closest thing to speakers, whereas the SR-009s are still blatantly headphones (which is fine, it's why you still listen to headphones). The sound is still in your head with the SR-009. The imaging of the SR-009 however is very impressive due to its speed, though not as much as the HD800s, which have that extra bit of space allowing more precise placements of various sounds. However, I do feel like the SR-009s do a better job in the sizing of the instruments and tones. I felt that the HD800s made tone and instruments larger then they actually were, whereas the SR-009 has more accurate sizing (not placement though). The Utopia's also do a good job of this, and are actually better then the SR-009s at this.
My Equipment and Biases
I run the SR-009s through a KGST, but have heard them through the Blue Hawaii, and various other DIY efforts. Now you can criticize me (and my 5k setup) for not having the last word in amping the SR-009s, but I highly doubt that they would ever have better dynamics then the Utopia, the Audeze's, or even the HD800 (which did actually have greater slam) on a well driven amp. The SR-009 was never design to have amazing slam or powerful dynamics, and while it has good dynamics, they just can't match traditional dynamic headphones in this category. It was never a focus to begin with, and that quality is very apparent when listening to the SR-009s
Conclusion
It all depends on what your looking for. If you want the clearest window into music, estats my friend, but you must be willing to trade the dynamics and low end slam for it.
Thanks and regards,
Steve