Audio Out Different from Retina Model MacBook Pro? I have somewhat of a weird issue. I have a client who wants to send their audio out from their MacBook Pro 15" Retina to their TV from the headphone jack output on the MacBook. The TV has a 1/8th audio input, so that all plugs in very nicely. After it's plugged in, the audio stops coming out of the MacBook's speakers, just like it would if you had headphones plugged in, but there's no audio coming out of the TV speakers. 

When I plug in my MacBook Pro 15" (not Retina) with this setup, the audio works just fine. Is there something in the Retina model that's blocking this? Any advice would be great. Thank you.
You say it works fine with your set up. Are you connecting to his TV?
If so, it points towards the issue being with his MBP.

One quick bit of troubleshooting you could try - plug a set of earphones into his MBP and ensure audio is being sent. That'll help to isolate the problem.