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I have a 2014 MacBook Pro Retina and a set of Logitech z906 speakers which has two TOSLink optical line-in ports. I bought a mini-TOSLink to TOSLink cable on Amazon which arrived this morning, and I gleefully plugged it in and fired up Logic and opened a surround-sound project.
I went to the audio settings and enabled Surround in the Advanced settings as so:
I then configured the Audio Preferences's Surround section under I/O Assignments to show as 5.1 and default to the WG-4 channel assignments as so:
The sound output is fine, except it's still in Stereo and the DSP in the amp is upscaling the signal to use the available channels, and unfortunately, no matter what I do, I only seem to be able to get stereo output. If I pan a channel towards the rear speakers, it's as if I just turned down the fader rather than sent it to a different channel.
If I load up the Audio MIDI Setup panel from Utilities, the Built-In Output only allows me to select Stereo under the Multichannel settings:
I find it very hard to believe that Apple would go to the expense of including a mini-TOSLink output in the MacBook Pro and then not support 5.1 through it, so I'm guessing I'm missing something here.
Does anyone know how I can complete my setup so that I can get 5.1 audio output?
Edit: I gather from discussions on Apple's support pages that Quicktime 'passes through' the 5.1 audio signal straight to the output without performing any processing on it, so I'm wondering if Logic is able to do the same. 'Passes through' sounds a bit hokey to me, though, if I'm being honest. :/ It still feels like there's a configuration option I'm missing, somewhere.
Audio Midi doesn't show this new device at all… it's not 'built-in audio' if you bought a toy to do it. – Tetsujin – 2014-11-28T21:12:33.253
It's not a device, TOSLink is the name of the optical cable connection used for S/PDIF. I—apparently, as I am beginning to discover, wrongly—assumed that if Apple have gone to the expense of including a digital optical output connection on their laptops, then they would use a DSP chip that is capable of outputting the sound setup that the people who are most likely to plug those cable in would expect. If anything's proving itself a toy, it's the bloody MacBook itself. >:/ – Benjamin Nolan – 2014-11-28T21:37:53.477
I'm not really up to speed on 5.1, but I've been an audio engineer for about 30 years… so forgive me if I know some bits but not others - S/PDIF & TOSLink I never thought were the same thing, S/PDIF can only carry stereo [or something like AC3, which is x.1 compressed into a stereo format, to be re-de-coded at the far end; not well, I may add], TOSLink can carry 7.1. I'd need to do some research, but I think we may be beyond the limits of SuperUser & into Sound Design territory, where you might find someone right on genre.
– Tetsujin – 2014-11-28T22:11:36.243Ah, I'll go ask there. It's beginning to look like it's not possible without buying a USB 5.1 DSP, which is annoying TBH, because if you're expecting me to pay £2,500 for a laptop you could at least throw the extra £30 at the DSP to support 5.1. >.< I'd /almost/ rather they didn't have the optical connection at all. >.< – Benjamin Nolan – 2014-11-28T22:46:18.273
1I feel your pain - though tbh, I've never used a puter's built-in audio, always used dedicated external DACs – Tetsujin – 2014-11-29T19:29:40.397