So the problem do not come from the speaker. The speakers works fine in bluetooth with my iphone, without changing anything on the speaker. I have read that there us to be bluetooth audio trouble with OS x 10.7.4 with sound quality decreasing rapidly, but here i have no sound at all !! If i disable the option 'use as an audio device' on the bluetooth/Onbeat awake menu, the sound comes from the MBP as usual. I tried many times to unpair/re-pair, stil doesn't give any sound. All the sound options seem to be fine, even bluetooth options. Of course, i checked that noise was not turned to mute (both on speaker and MBP). When i launch a music on Itunes or any other 'noisy' file, the 'bluetooth' light on the speaker is not flashing anymore which indicates that it communicates with the MBP but. MBP and speaker pair well, the speaker is recognize by the MBP, even indicated 'connected'.
I just bougth a JBL Onbeat Awake speaker in order to get bluetooth audio service with my MBP.