Hi - my MBA is late 2012 (8 GB, 2 GHz i7, 10.7.4). When I hook it up to the LED TV (a Toshiba 40L2200U) using a Folsom miniDisplayPort to HDMI cable (no separate adaptors, it's a 6' cable with mDP at one end and hdmi at the other) it works fine - audio is transmitted and it comes through the TV speakers. But when I close the lid and try to continue watching with the laptop in clamshell mode (a magic trackpad is around that is paired to it), video continues just fine but the audio cuts out. Annoyingly, when I open it back up the audio still doesn't work. I have to futz around a while before it comes back (restart programs with audio, unplug the cable and plug it back in again, move the audio in system preferences to the native speakers and back again etc.) Does anyone know what's up with this? I don't think it can be the cable's fault--clearly it's able to transmit audio along with the video, and nothing changes about the cable when I close the lid.