I've been looking to get a pair of electrostatic headphones for awhile and was thinking about the Stax SR-L700s. As I have never listened to any electrostatic headphones before, I didn't want to spend that kind of money only to realize that I didn't like them.
I saw the first Massdrop for the Koss ESP/95X headphones but by the time I had finished researching, the drop had closed. I thought I had missed my chance for a reasonable priced pair of stats headphones but back the drop came and I was ready this time. :)
Let me say that I am very impressed.
Unpacking and Assembly
So the headphones shipped soon after the close of the drop and I received them a week later. The phones and amp arrived double boxed. The original Koss box inside contained the E/90X amp/energizer, headband, left and right earspeakers (to use Stax's terms) and power adapter for the amp/energizer. It was easy to assemble the headphones. Just follow the instructions provided by Koss' instruction manual and make sure you hear a slight click when you insert each padded cup assembly into the headband. Also, included was a link to register for your lifetime warranty.
Let's just say that you almost forget you are wearing headphones. I only know that I am wearing them because I broke my normal pair of reading glasses and am wearing another pair with thicker arms. The headphones clamp lightly relative to other headphones. They may clamp more than Sennheiser headphones but not by much. My temples are very sensitive to pressure and these headphones (BEFORE breaking my original reading glasses) do not cause me any discomfort.
These headphones are amazing. They only require a few hours of burn in if at all.
Please note that I have not listened to any other headphones since I received the Koss ESP/95X so I have not compared them to my HifiMan's for example. I will do that sometime but I am just loving the music for the moment.
They are very spacious. I have several other pairs of headphones (HifiMan HE-400i, Audio Technica, Sennheisers (not the really expensive ones), M&J MJ2) and none of them are as spacious as these. I am sure that there are very expensive headphones out there that are more spacious but these cost me $500. This is basically the same price as I paid for my HifiMan's. The sound stage is a bit wider than what I am used to on my other headphones but not artificially wide. These are the first headphones where there is actual depth in the sound stage. I was very surprised by that.
They are very revealing. Currently, I have them hooked up to an iFi-Audio DAC2 which I have in my home office and I am hearing how the DAC is limiting my listening experience. I am hearing a slight harshness to the sound which I could not perceive on the other headphones. However, they are not revealing to the point of being fatiguing. In fact, far from it.
They are detailed. Again, this is not to be point of being fatiguing. On very familiar tracks, I hear instruments and sounds that I have never heard before. The cymbals on 'The Bangles Return Post' are just exquisite. If it is on the recording, you will hear it with these headphones.
These headphones are not for bass heads. However, this does not mean they do not have bass. The bass is natural and extended to the lower frequencies. If the bass is there, you will hear it. They have just enough bass for me.
The midrange is wonderful. Female vocals just make you want to cry. The midrange in general is great but female voices really show the quality of the midrange.
I have touched upon the treble already but let's just say that it is detailed, non-fatiguing and extended.
I am very happy with my purchase.
Now, I have read that the Achilles heel of this setup is the energizer. I was considering upgrading the power supply as that is supposed to help as well. However, since I wanted to purchase a Stax earspeaker anyway, I have ordered the Stax SRM-353X and an adapter cable from Fong Audio. This way I can improve the sound of the Koss headphones and be prepared for a possible future Stax purchase.
I will update with my thoughts when the Stax setup is in place.
Update 1 - I forgot to thank Massdrop and Koss for making this package available at this price.
Update 2 - While I wait for the SRM-353X, I decided to use a different power supply. I have a Booster BOTW 9v supply that I use on my Sonore ultraRendu/ultraDigital combo. This power supply improves the sound a bit. The instruments appear to have more body and a longer decay. Also, there appears to be better instrument focus. Maybe, there is a lower noise floor which is contributing to all of these improvements. The bass seems to be tighter and might go even lower then before. The cymbals on the aforementioned 'Return Post' are even better. I can distinctly hear the stick and then the shimmer of the cymbals. Dire Straits' 'Your Latest Trick' has even more depth than before. This is still with the iFi-Audio DAC2. I'm sure the DAC is really limiting me here.
I can't wait for the Stax energizer.
Update 3 - The Stax SRM-353X arrived on Friday. I connected it and listened to it as soon as I powered it on. I am not impressed so far. I thought that the sound stage was narrower and the bass was not as tight or present. The midrange was still good though. I am hoping it needs some burn-in. There is also the fact that I am using a pair of RCA cables between my iFi-audio micro DAC2 and the Stax instead of the 3.5mm cable I used with the Koss E/90X which was connected to the headphone output of the DAC (I wanted to control the volume via the DAC so I didn't change the balance on the energizer. Also, I have the adapter cable connected between the headphones and the Stax. Keep in mind that I am comparing the SRM-353X to the E/90X powered by the Booster power supply. I am going to let the whole setup burn-in a bit and will report back.
Update 4 - The Stax SRM-353X now has several hours on it (maybe 12). I now find that the tremble is more extended than the Koss E/90X - Booster PS setup. All instruments seem larger more formed let's say. I have not been listening to the setup during burn-in. I have been listening periodically to check in on any changes. Soon, after a bit more burn-in, I will make a comparison between the Koss E/90X - Booster PS setup and the Stax SRM-353X setup at the same volume using a sound meter so differences in loudness isn't an issue.