I was looking at Brainwavz S1 and R3 specs on their official website: http://www.yourbrainwavz.com/index.php and I realized that their declared Max Input Power is only 2mW and their sensitivity is also pretty low (around 93/95 dB at 1mW).
Most headphones I've came across have declared Max Input Power above 20mW, which is, as far as I understand, pretty logical since even a small iPod Shuffle is supposed to be able to deliver much more than 2mW into a 16/32 Ohms load.
I wonder whether this (2mW) value is not correct, or if this IEMs are that fragile (electrically).
I've sent an e-mail to email@example.com asking if the Max Input Power declared on their website is correct or not, but I haven't received any answer yet.
This is a list of other IEMs Max Input Power:
VSonic GR99: 30mW
VSonic GR07: 50mW
Yamaha EPH-50: 50mW
Shure SE535: 50mW
Hifiman RE400: 30mW
Maybe I'm missing something... What do you think?