Trying to clarify HTPC multi-channel room correction - AVS Forum
Forum Jump: 
 1Likes
  • 1 Post By 3ll3d00d
 
Thread Tools
post #1 of 12 Old 07-07-2014, 08:02 AM - Thread Starter
Member
 
12B4A's Avatar
 
Join Date: Mar 2014
Location: CR Iowa
Posts: 19
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 11
Trying to clarify HTPC multi-channel room correction

The goal is to have an HTPC movie/tv playback of DD/DTS multi-channel audio encoded content in a system where the audio will have room correction applied.

Currently my setup is a Mac Mini to an Emotiva UMC-200 that outputs analog audio to a 7.1 amplifier and video to a front projector.

It looks like the PC software solutions (Dirac, REW, etc.) for room correction would not work at the Mac Mini level during playback due to the DD/DTS encoding. With the software, I would be able to measure the speaker/room interaction and generate a corrected curve but I would not be able to apply that curve at the Mac Mini level since it would involve decoding DD/DTS, processing the decoded result, and then re-encoding to send to DD/DTS decoding hardware downstream (UMC-200 in this case). The software would need a DD/DTS license in order to do this and I don't see any indication of any PC software solution with a license.

It seems like in my situation, I would need a hardware solution between the DD/DTS decoding device and the amplifier (A/D, processing, then D/A back to amp) in order to implement the corrected curve.

Am I missing something here? I'd love to be wrong if there were a simpler setup.
12B4A is offline  
Sponsored Links
Advertisement
 
post #2 of 12 Old 07-07-2014, 08:21 AM
Advanced Member
 
3ll3d00d's Avatar
 
Join Date: Sep 2007
Location: London, UK
Posts: 578
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 238 Post(s)
Liked: 79
You decode on the PC, apply correction and then send multichannel PCM to the processor. There should be no need to re-encode back to DD or whatever.
IgorZep likes this.
3ll3d00d is offline  
post #3 of 12 Old 07-07-2014, 08:38 AM
AVS Special Member
 
markus767's Avatar
 
Join Date: Apr 2009
Posts: 5,303
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 795 Post(s)
Liked: 317
Quote:
Originally Posted by 12B4A View Post
Emotiva UMC-200
The UMC-200 has a built-in EQ. Why don't you use that for room correction?

Markus

"In science, contrary evidence causes one to question a theory. In religion, contrary evidence causes one to question the evidence." - Floyd Toole
markus767 is offline  
post #4 of 12 Old 07-07-2014, 09:07 AM - Thread Starter
Member
 
12B4A's Avatar
 
Join Date: Mar 2014
Location: CR Iowa
Posts: 19
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 11
Quote:
Originally Posted by 3ll3d00d View Post
You decode on the PC, apply correction and then send multichannel PCM to the processor. There should be no need to re-encode back to DD or whatever.
I will try this later today with Plex. It's a bit ambiguous:
Quote:
Originally Posted by Plex Page
Audio Output Channels
This option leads to a lot of misconceptions. This option is only used when not using passthrough. For example, when you have DTS unchecked but LPCM enabled it will transcode DTS audio to the number of channels configured here. Configure this option to match up with the number of speakers you have, but don't expect it to be used if you only play encoded audio.
Quote:
Originally Posted by markus767 View Post
The UMC-200 has a built-in EQ. Why don't you use that for room correction?
Their EMO-Q automated setup produces inconsistent results from one trial to the next. In addition it often fails to register the center and/or one or both of the surrounds. It is logically possible to manually adjust all channels but that would be rather tedious to do through their on-screen GUI.
12B4A is offline  
post #5 of 12 Old 07-07-2014, 09:52 AM
Advanced Member
 
3ll3d00d's Avatar
 
Join Date: Sep 2007
Location: London, UK
Posts: 578
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 238 Post(s)
Liked: 79
Quote:
Originally Posted by 12B4A View Post
I will try this later today with Plex. It's a bit ambiguous
It looks like you just need to set that to the no of physical channels you have & then use PCM/Direct as the output format.
3ll3d00d is offline  
post #6 of 12 Old 07-07-2014, 12:06 PM
AVS Special Member
 
markus767's Avatar
 
Join Date: Apr 2009
Posts: 5,303
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 795 Post(s)
Liked: 317
Quote:
Originally Posted by 12B4A View Post
Their EMO-Q automated setup produces inconsistent results from one trial to the next. In addition it often fails to register the center and/or one or both of the surrounds. It is logically possible to manually adjust all channels but that would be rather tedious to do through their on-screen GUI.
You can adjust EQ manually. Isn't that what you want? If you want fully automated room EQ then get an AVR.

Markus

"In science, contrary evidence causes one to question a theory. In religion, contrary evidence causes one to question the evidence." - Floyd Toole
markus767 is offline  
post #7 of 12 Old 07-07-2014, 01:50 PM - Thread Starter
Member
 
12B4A's Avatar
 
Join Date: Mar 2014
Location: CR Iowa
Posts: 19
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 11
Quote:
Originally Posted by markus767 View Post
You can adjust EQ manually. Isn't that what you want? If you want fully automated room EQ then get an AVR.
That's one possibility. Fully automated is also possible with a PC software implementation (if I can manage to get LPCM out of the Mac) and I wouldn't have to change any hardware.
12B4A is offline  
post #8 of 12 Old 07-07-2014, 02:00 PM
AVS Special Member
 
markus767's Avatar
 
Join Date: Apr 2009
Posts: 5,303
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 795 Post(s)
Liked: 317
Quote:
Originally Posted by 12B4A View Post
That's one possibility. Fully automated is also possible with a PC software implementation (if I can manage to get LPCM out of the Mac) and I wouldn't have to change any hardware.
What software/hardware do you have in mind?

Markus

"In science, contrary evidence causes one to question a theory. In religion, contrary evidence causes one to question the evidence." - Floyd Toole
markus767 is offline  
post #9 of 12 Old 07-07-2014, 04:53 PM - Thread Starter
Member
 
12B4A's Avatar
 
Join Date: Mar 2014
Location: CR Iowa
Posts: 19
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 11
I'm happy with the results from the Dirac Live trial version in 2 channel mode. I've also tried the Fuzzmeasure 3 trial and REW.

As far as hardware, if I take in to account what I would get for selling my separates and the cost savings of not going for Dirac Live, I think the Denon AVR-4000P fits my ideal with maybe something one or two steps down in the line if I'm feeling pinchy. The only unanswered question here is if Audyssey is a comparable performer to Dirac Live. I've read too many arguments to make a clear decision on that.

Those are the strongest possibilities to me unless there are better suggestions.
12B4A is offline  
post #10 of 12 Old 07-08-2014, 12:11 AM
AVS Special Member
 
markus767's Avatar
 
Join Date: Apr 2009
Posts: 5,303
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 795 Post(s)
Liked: 317
Quote:
Originally Posted by 12B4A View Post
I'm happy with the results from the Dirac Live trial version in 2 channel mode. I've also tried the Fuzzmeasure 3 trial and REW.

As far as hardware, if I take in to account what I would get for selling my separates and the cost savings of not going for Dirac Live, I think the Denon AVR-4000P fits my ideal with maybe something one or two steps down in the line if I'm feeling pinchy. The only unanswered question here is if Audyssey is a comparable performer to Dirac Live. I've read too many arguments to make a clear decision on that.

Those are the strongest possibilities to me unless there are better suggestions.
Not sure what you want. With REW and the UMC-200 you already have a multichannel room correction solution. All you need to do is learn REW and waste considerable time on setting things up.

Dirac Live isn't available as a multichannel box. It is available in the Datasat RS20i and Emotiva claims that they are working on an processor with Dirac Live.

There was a box from Audyssey but it is no longer available. XT32 is available in various AVRs.

The only solution for processing audio in real time before it is sent out of your PC would be AcourateConvolver or Dirac Live (8 channel version).
Another solution is a separate PC that does the audio processing.
Both solutions are rather shaky because of HDCP issues.

PEQ, Audyssey, Dirac Live and Acourate are all different room correction solutions. They follow different strategies to solve the problem but Audyssey and Dirac Live don't disclose what they are doing.
Again with REW and PEQ you already have a solution that gives you full control over the optimization process. It even allows you to do things Audyssey and Dirac don't offer.
Good paper that scratches the surface of the problem: http://www.dirac.se/media/12044/on_room_correction.pdf

Markus

"In science, contrary evidence causes one to question a theory. In religion, contrary evidence causes one to question the evidence." - Floyd Toole

Last edited by markus767; 07-13-2014 at 04:56 AM.
markus767 is offline  
post #11 of 12 Old 07-08-2014, 05:14 AM - Thread Starter
Member
 
12B4A's Avatar
 
Join Date: Mar 2014
Location: CR Iowa
Posts: 19
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 11
Yep, I don't know what I need either. Having discussions like these do help inform though and I'm glad you're taking the time.

One little technical hitch I haven't mentioned that's playing a big influence here is that I'm having an EDID interaction problem with the UMC-200 that is, so far, a unique encounter. I'm unable to send out any audio over HDMI from the Mac due to the UMC-200 not telling the Mac it is a valid audio downstream component only when connected to the projector. Connecting to an audio-less computer monitor or TV produces the desired audio over HDMI. I work around this by using the optical output which passes encoded DD/DTS stuff but limits PCM audio to 2 channels only. So LPCM multichannel is a possibility coming from the Mac but...

I've gotten no word back from Emotiva which makes me disinclined to spend any more money with them re: XMC-1 with Dirac Live. I think in order to solve the problem I just have to change one little bit in an EDID file but knowing what to change, how to change it, and where it needs to be changed is going to involve becoming 1/4 to 1/2 an expert on EDID.
12B4A is offline  
post #12 of 12 Old 07-11-2014, 09:41 PM - Thread Starter
Member
 
12B4A's Avatar
 
Join Date: Mar 2014
Location: CR Iowa
Posts: 19
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 11
Update for anyone who might run in to this or similar problem: I had to get an EDID spoofer (Dr HDMI in this case) to get everything working but only after putting in line after substituting a panasonic plasma for the projector. The Dr HDMI didn't enable full 8 channel audio with the full HD presets when it was between the Mac and the UMC-200 in any case.

Mac--> UMC-200--> JVC Projector = HDMI audio disabled, 2 channel optical audio working
Mac--> Dr HDMI (any EDID preset)--> UMC-200--> JVC Projector = HDMI audio enabled for 2 channels only from the Mac
Mac--> Dr HDMI (any EDID preset)--> UMC-200--> Panasonic Plasma = HDMI audio enabled for 2 channels only from the Mac
Mac--> UMC-200--> Panasonic Plasma = HDMI audio enabled for 8 channels from the Mac
Mac--> UMC-200--> Dr HDMI (sponged EDID)--> JVC projector = HDMI audio enabled for 8 channels from the Mac
12B4A is offline  
Reply Audio theory, Setup and Chat

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off