MacOS – Does the MacBook Air Support 5.1 Surround Sound

If you want to have 5.1/7.1 (multichannel) audio, you can do it via the optical out (mini-toslink), the HDMI or the Mini-Display Port.

On the receiver side, you must have a decoder, able to decode the stream (PCM for 2 channels and DD/AC3/DTS and their variants) and convert it to analogue signal.

I had the same dilemma when I got my ATV2, I wanted something to be able to utilize my optical SPDIF, and to be able to decode Surround sound. After doing some research, there were several solutions:

• Optical->RCA analogue convertors. Stereo only, like GefenTV. This doesn't do multichannel.
• A small size 5.1 Decoder - you can read the HD Audio Rush review here.
• A Logitech Z-5500.
• Full-blown 5.1/7.1 amplifier.

Personally I decided to go with the amplifier and bought a Pioneer 7.1 receiver.

Unfortunately, Mac OS X has fairly limited multi-channel audio support. It can stream already-encoded Dolby Digital or DTS audio from a DVD (and programs like VLC can do this from other file formats) but it doesn't provide a means of expanding stereo sound to more channels. Futhermore, Toslink only has enough bandwidth for uncompressed stereo or Dolby/DTS-encoded multi-channel, so you'd need to encode the audio to one of these formats on-the-fly -- this is another feature Mac OS X lacks.

It's generally up to your audio receiver to provide a means of expanding stereo sound to utilize multiple speakers. Does your digital surround system have an option for Dolby Pro Logic or DTS Neo? These are other popular algorithms for expanding two-channel sound to multiple speakers.