PDA

View Full Version : Multi-channel audio files and downmixing 5.1 to 4.0 help please



windhoek
17-10-2014, 12:32
I've got a lot of multichannel audio files on my HTPC and in the very near future, will have a quad setup in place and would appreciate some help in working out how best to play those files in 4.0 surround sound. Let me first say what kit I will have help to identify what's needed.

Source: HTPC (JRiver)
Front Amp: Teddy Pardo Pre/ Power combo
Front Speakers: ATC11s

Rear Amp: Teddy Pardo Poweramp
Rear Speakers: ATC7s

The way I see it, I've got two options:

A: Use HTPC to play m/c SACD ISO files and use Jriver to downmix (if possible) and stream to external processor/ DAC
B: Use HTPC to play m/c SACD ISO files and use external processor/ DAC to downmix

Whichever option I choose, the external processor/ DAC needs to support m/c audio via USB or HDMI.

My back up option is to use my OPPO 103D to spin and downmix SACDs to 4.0, but that defeats the purpose of ripping my m/c SACDs and is probably the last resort. there's not much on the web about this sort of stuff, so if anyone has done something similar, please share your experience/ knowledge. I know I could just buy an AVR with HDMI inputs, but I don't have space for another big box and the good ones invariably are!

Thanks,
Derek

windhoek
18-10-2014, 06:02
I think I have the answer and I was looking at it all along :doh:

All I need to do is attach a HDD containing my m/c DSD files (or use my OPPO to pull the audio from my HTPC via the wifi router) and set the OPPO to convert DSD to PCM. Once I do that, I can apply speaker management to downmix 5.1 to 4.0 and adjust speaker levels. I thought I'd probably have buy an external processor of some sort to play m/c DSD files from a hard drive/ PC, but it looks like the OPPO can deliver once again. The whole point of doing it this way rather than simply spinning discs is that streaming allows greater buffering and therefore, should make for a more accurate read of the data, at least, I think that's why streaming is preferable to spinning discs.

The only thing the OPPO won't do is apply EQ, but considering I'll be using ATC 11s at the front and 7s at the rear from the same product period (i.e. 2013 versions) and Teddy Pardo amps for the front and rear speakers, the front and rears should be sonically concordant with one another. :)

windhoek
02-01-2015, 12:53
Finally, after what seems like an interminable period of time, I now have m/c playback :)

In the end I've had to shelve plans to use my HTPC as source and processor for m/c music because I can't afford an Exasound E28 DAC and the Dirac Live software I'd probably want to use to make sure the sound is EQ'd to compensate for room inadequacies etc; besides, I'm not confident my PC skills are sufficiently good to ensure Dirac applies optimal correction, so I'd probably need to pay someone to do that on my behalf. The solution I chose therefore, was to stick with disc playback for the foreseeable future and simply send m/c PCM from my BDP to AVR, where DSP trickery such as downmixing audio to 4.0 and room correction can be applied. Here's the audio flow I use to achieve this:


Digital (2.0):
HTPC>Lavry DA11>Teddy Pardo i80a>ATC SCM7

Digital (4.0):
(f): OPPO 103D>Marantz NR1504>Teddy Pardo i80a>ATC SCM7
(r): OPPO 103D>Marantz NR1504>ATC SCM7
(c): no centre
(s): no sub

As you can see, I still use my HTPC as source for stereo digital playback and disc playback via my OPPO and AVR for m/c audio.

Fwiw, I tried using my OPPO as source, processor (i.e. downmixing audio to 4.0 and adjusting speaker distance and levels), DAC and preamp, but it sounded absolutely terrible and I knew very quickly that without decent DSP trickery, my plans to have a good 4.0 setup would be dashed. The Marantz was fairly cheap at 250 and fortunately has Preouts for the front channels to allow my main stereo amp to drive the front speakers while the AVR drives the rears. But not only do I have a fully functional 4.0 setup, it sounds fricken' awesome!

I may revisit plans to use my HTPC as source for m/c audio in the future, but unless AVRs begin to support m/c audio via Async USB, I'll probably keep things as they are; that reminds me, I don't have space for a big AVR, so the Marantz 1504 (or similar Marantz models) was the only AVR I could use due its low profile and front channel Preouts.

Brigadoon
16-05-2015, 07:20
Does the Marantz not allow you to specify your speaker setup and then down mix accordingly? My Sony does