I already told you about my electrostatic headphones in previous post and now it’s time to look at another very interesting headphones from Stax that was made roughly at the same time. SR-40 is not an electrostatic headphones but “electret” ones. It’s very similar to electrostatics, only membrane there is thicker and already hold an electric charge to react in static field. With precharged membrane there is no need for addition electricity circuit just for build up a static charge, so it helps to reduce production cost. Beside it, electret technology considered inferior to electrostatics. Actually, all those electret headphones from Stax are dirt-cheap compared to more elaborate electrostatics and you can get them from Ebay for mere 50$-100$. So I decided that it’s not too expensive and have got one for myself.