Hello,
As I promised in the last post I will describe the mod that drastically increased the sound flowing from my new Stax SRS-3100 system.
* First of all, almost everything is solid plastic so between the part with pad and rest of headphone there is a space that always will have some sound leakages (this ellipsoid place), it will never be perfectly close together because of its plastic nature.
You can avoid it by placing there 1-2mm thich ductile tape.
After that we have low-bass frequency corrected a bit.
* Next SUPER-IMPORTANT thing that works probably only with electrostatic headphones (doesn't work with dynamic and planar headphones - yes I checked on my own) - we can easily do something that hugely improves low and low-mid ranges, have more mass in sound, bass line is fuller and more present, more dense and lasts longer. In addition we have much wider sound-stage and this is all without any negative changes in the rest of frequencies (higher mid and highs).
OK then what needs to be done to achieve it? (I don't know if what I have done in the first point has any meaning here because I tried this after that). Having headphones on head, catch them by fingers and pull off the head very little, few millimters, try few distances.
Good test is listening to this playlist from 30 to 60hz and checking what distant from head makes bigger difference for you:
How to sustain this distance from the head is not hard to discover I suppose
The final result:
Now the question is, why it works that way? I have some suspicions. Maybe because of the very construction of electrostatic headphones and the big size of surface that produces the sound-wave. Making a little bit of space between the head and pad let the sound waves flow around the head and some parts of frequency (especially low and low-mid) interfering with eachother making certain range fuller.
Ps. I warn you, if you have thought that Stax headphones have no isolation - try it now : P