I tested these headphones in several configurations:
- Connected to the PC via a sound card (very well made) with the jack: a downright smothered, lots of bass, no treble, horrible. Even with the equalizer there was nothing to be learned.
- Connected to a smartphone via jack: same as for the PC.
- Connected to the PC via Bluetooth 4.0 Key: Its average still too low but the sound is less muffled. Correct equalized once but unfortunately it can not be done by applying an application. So not practical.
- Connected to a smartphone via Bluetooth 2.1: same as for the PC
- Connected to the PC with the USB cable: a bit better than Bluetooth, but is always a way. handy if there is no battery but think to offline bluetooth otherwise it beeps continuously.
I have not tested long enough (my ears have not supported) to judge autonomy.
Given the very positive but former opinion, and rather recent negative reviews, I would bet on a bad run or a change in components to explain this. Especially since the few journals made by audiophiles on the net is positive.
I leave 2 stars: One for comfort (very light and does not heat the ears And the price for having received offers flash it interesting..
Helmet returned the day after the delivery.