Home Theater Amp

[fretfingers]

I would like to monitor my ProTools sessions in 5.1 via my living room home theater system. Does anyone know of a box that will convert an ADAT Lightpipe stream into either an HDMI (LPCM) output or a Dolby Digital AC3 stream (via optical)?

Thanks

[Darryl Ramm]

Not exactly what you are asking but one option is to get a MacBook Pro or Mac Mini or the new Mac Pro with HDMI output. And use that HDMI output as your playback engine. You need a receiver that will do 6 channel PCM. You also *might* be able to do this on your Mac Pro with a HDMI capable graphics card.

Other options are just using Neyrinck SoundCode and exporting a Dolby digital file. http://www.neyrinck.com/soundcode-fo...gital-features. Also not what you are after as its not real-time playback. I'm not aware of any convertor box etc. that will do exactly what you are asking, not that I've ever looked hard.

[nst7]

I just recently posted about how to do this. If you have any Mac that's from 2010 or later, you can actually send multichannel HDMI out from your Mac with a simple Minidisplayport to HDMI adapter (from your signature it appears you have the current quad 3.2, so that will definitely work).

I only recently found out about this capability. Basically the HDMI protocol is built into the recent Macs, even if they don't have the physical HDMI output jack.

To verfy that your Mac has this capability, go to the upper left Apple icon, select "About this Mac">"more info">"system report">"hardware">"Audio (built in)". Over to the right you will see all your Mac's options including line out, headphone out, digital out, etc. Down at the bottom you will see "HDMI / Displayport output". If that last thing is listed, then your Mac has this capability. You just need the adapter and cable and you're good to go.

What you'll be doing is sending multichannel PCM audio out. Most recievers will accept that. No need for encoders/decoders, etc.

This is the adapter you need:

http://www.bestbuy.com/site/DisplayP...port&cp=1&lp=4

Amazon has it even cheaper, and you can just have Best Buy match the price (sometimes they'll calculate the match with shipping added):

http://www.amazon.com/gp/product/B00...A1C9SLS6HT1I6Z

And of course you'll need an HDMI cable of whatever length you need.

I've been using this from my 2010 Mac Pro into my home theater receiver (they're both in the same room). With a single HDMI cable, I not only get the multichannel audio, but my TV (hooked up by HDMI to the receiver) is seen by the Mac as a 2nd display, where I have the typical options of using it for extended desktop, or mirroring mode, just like I would with any other display.


So as not to waste more space, I will link to my original posts where I describe how to set this up:

http://duc.avid.com/showthread.php?t=341812

Let me know if you have more questions about it.


Note that I have not said anything about using optical cables, because I briefly tried it and was not able to get it to work.

But theoretically, you should be able to just go into your reciever's optical inputs, and the same principle applies, in that you're sending straigh PCM out with no need for encoding/decoding. So all you should need is an optical cable.

I have a cheap reciever, and I did not spend much time trying to mess with it. When I couldn't get it to work, I decided it was more convenient the other way. But your experience may differ, so it may work better for you.

I like the fact that using the HDMI from the Mac also lets me use my big screen TV as an additional monitor for the computer as well.

[fretfingers]

Thank you very much! That was super helpful! I do need to keep my hdx rig running while monitoring surround but I can pipe the audio to my laptop and then go hdmi from there.

I just realized though... My amps optical in says that it supports PCM audio. Does that mean I could just directly connect the Adat out of my interface to my amp?

[dj_grimmace]

No, you can't pipe adat lightpipe into your optical input. I've actually been looking around for an analog to ADAT converter for a while now, and the only option seems to be to buy a usb interface with adat outs.

Regardless, if you could go out of your PT rig analog, you could use this nifty guy

http://www.amazon.com/GefenTV-HDMI-P...I1UUITHEAOIOGL

You could also buy the neyrinck plug in to convert your pt output to dolby, which would allow you to connect directly to your receiver from your optical out:

http://www.neyrinck.com/soundcode-for-dolby-digital

[nst7]

So the reciever's optical input will only recieve an encoded signal rather than straight PCM? That explains why I couldn't get it to work.

[Darryl Ramm]

what exactly it does will depend on the processor/receiver, most will do stereo PCM, Dolby Digital and/or DTS on the TOSLINK input. But not > 2channel PCM (consumer stuff does not do ADAT/SMUX).