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Talking Heads 5.1 Downmixes

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windhoek

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Here's an interesting oddity. Someone has downmixed the Talking Heads 5.1 releases to stereo and although it seems like a bizarre thing to do and perhaps odd to talk about it here at QQ, the downmixes seem to offer something new. Robin Sharoma, the guy who made the new mixes, reckons the 5.1 mixes are more dynamic for a start, so pulling that back to a stereo mix, should result in a stereo mix with better dynamic range. He also reckons there are other upsides about doing this including iirc, that the 5.1 mixes were created using the original multitrack tapes. The upshot of which is, the downmixes are almost certainly going to sound different to most other stereo releases, if not all - whether that includes vinyl, I don't know.

I downloaded all the albums last night and the dynamic range is very good and the music does indeed sound different to the stereo versions that come as part of the CD/DVD-A releases. Do I like them? In a word, yes! :)

I'd be happy to share the download link with anyone, but in any case, you'll probably want to click here at Robin's website where he talks about the project before doing anything else. Fwiw, the downmixes aren't directly available to download from his website.
 

Franklin

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So wouldn't it skip a stage or two to just set the player to downmix, then pro logic it at the amp?
 

windhoek

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That's a good question. I can only speculate that if that was the case, Robin wouldn't have went to all that trouble to create downmixed files.

I'm at work, but when I finish tomorrow, I'll see if I can try that out. I imagine I should be able to output 5.1 from my OPPO and force a downmix to stereo with my AVR. I'll update the thread with the results...
 

Ninecats

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I have no insight in downmixing, but as I've stated in a poll for one of these releases, yes the stereo versions of the CD/DVD package are not very good. The original vinyls have much better sound. Way more dynamic in the multichannel option, however, they all sound very good!
 

Franklin

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That's a good question. I can only speculate that if that was the case, Robin wouldn't have went to all that trouble to create downmixed files.

I'm at work, but when I finish tomorrow, I'll see if I can try that out. I imagine I should be able to output 5.1 from my OPPO and force a downmix to stereo with my AVR. I'll update the thread with the results...
That sounds a bit more complex for the amp - two processes. I've got some Talking Heads in 5.1 so I could give it a go here. FWIW, and you probably know this, an AV amp via HDMI can be forced into downmixing if connected by HDMI to a stereo TV and set to dual (rather than seperate). I guess I could try both downmixing at the player stage and at the amp stage and see if either works better than the other.
 

windhoek

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That sounds a bit more complex for the amp - two processes. I've got some Talking Heads in 5.1 so I could give it a go here. FWIW, and you probably know this, an AV amp via HDMI can be forced into downmixing if connected by HDMI to a stereo TV and set to dual (rather than seperate). I guess I could try both downmixing at the player stage and at the amp stage and see if either works better than the other.
That's a very good idea Mike. I'll probably start off with the LOVE DVD-A by The Beatles because that's a multichannel-only disc and if I can get that downmixed to stereo via HDMI to my AVR (whether using my TV to help out), then hopefully the same results can be achieved with a 5.1 source via HDMI to my AVR.

On the fly downmixing might be simpler, but I'm not sure why Robin wanted 5.1 downmixes in the first place. Perhaps he didn't have a multichannel setup at the time or simply wanted better stereo sources to play in stereo-only setups. Who knows. But I look forward to experimenting tomorrow and hearing about what you discover too - or not as the case may be :)
 

zeerround

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When downmixing one has to decide how much C to but in L and R, how much LFE (if any) and how much LS and RS. Sadly, there doesn't seem to be a standard, with different hardware doing different things, and some formats allowing the producer to decide ahead of time.

So, your downmix in hardware might come out different than "downmixed by someone".

I would argue that downmix should match what would happen at the listening position in an ITU 5.1 setup (in terms of levels of the different channels), however most downmix implementations are going to drop the rears by some amount.

Also, I didn't understand the reference to pro-logic. What is that for? If you have multi-channel listen to the 5.1 in multi-channel.
 

Franklin

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If you have multi-channel listen to the 5.1 in multi-channel.
Yeah, that's a strange one, but it appears to be suggested that the decoding is different. That's non-commital comment at its finest.
 

windhoek

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I spent the last 30 minutes or so experimenting with on the fly downmixing and I think it's safe to conclude, downmixed music sounds different to the stereo equivalent: sometimes for the better, sometimes not.

I achieved this by adjusting my AVR's speaker setup to front Left and Right only to ensure all multichannel audio was downmixed and used my HTPC to switch between various stereo and m/c tracks of the same album. With regard to Talking Heads, The downmixed intro to The Overload sounded better and more dynamic than the stereo version, but the glissando bass intro to Road To Nowhere doesn't appear in the downmixed version (whether played in 5.1 or downmixed) and I think the song is better with the bass slide, as found on the stereo version. So in that instance, I think the stereo version is better. I did the same with other songs and with other artists and again, the results varied.

So the results achieved by Robin Sharrock can be replicated simply by tweaking the settings of our hardware to force downmix to stereo on the fly. I suppose if one wanted a downmixed file to play in a stereo only system, such as through headphones with a portable MP3 player, then creating new files could be useful. And there is undoubtably some merit in downmixing if it sounds better than the stereo equivalent as well as the multuchannel mix. Considering there are some duff multuchannel mixes out there, it might even be the best option! An opportunity for further experimentation :)
 

Franklin

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...the glissando bass intro to Road To Nowhere... and I think the song is better with the bass slide, as found on the stereo version.
Yeah, that sticks out like a sore thumb. I don't think it works better for being cut.
 

alk3997

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That's a very good idea Mike. I'll probably start off with the LOVE DVD-A by The Beatles because that's a multichannel-only disc and if I can get that downmixed to stereo via HDMI to my AVR (whether using my TV to help out), then hopefully the same results can be achieved with a 5.1 source via HDMI to my AVR.

On the fly downmixing might be simpler, but I'm not sure why Robin wanted 5.1 downmixes in the first place. Perhaps he didn't have a multichannel setup at the time or simply wanted better stereo sources to play in stereo-only setups. Who knows. But I look forward to experimenting tomorrow and hearing about what you discover too - or not as the case may be :)
An interesting disc you bring-up from a downmix standpoint. The downmix coefficients for the Love DVD-A are not correct. They result in too much level going to the front left/right channels if you play the disc on a stereo system that implements the downmix correctly.

I know this because my wife had a Lexus with a "funky" Mark Levinson system. This was before true 5.1-channel was implemented but after DVD-Audio was added to the Levinsons. What that system did was to take whatever source was used, convert it to stereo and then create a synthesized surround output. So, it actually downmixed 5.1-channel to stereo, using the coefficients when possible, and then recreated the "surround experience" from the downmixed stereo input.

Any time I'd try to play the Love DVD-Audio disc in that car (which we no longer have) any loud peaks would distort. Only disc that did that. I was able to check with someone at the company who confirmed that was the likely source and it's the only reason that made sense.

So, if your downmix of the Love DVD-Audio disc isn't quite "right" then it's not your system that has a problem. I'm sure there are probably some systems that add extra headroom but that wouldn't be accurate.

Bottom line if you don't account for the possibility that adding front left and rear left will result in twice the maximum level the system can handle, then you might get digital distortion when you play the combined channels back.

Andy
 

zeerround

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That's why I posted about the difference between letting your hardware do it and somebody doing it in software.

I haven't seen any mix down coefficients that are technically correct for music (all channels should result in the same volume at your ear, as they would have in the 5.1 case). -3dB rears, "dialog normalization" on the center, no LFE, etc. etc.

Then there's the problem you highlighted, Lazy producer not checking for mixdown clipping when setting the coefficients (probably just took the default).
 

zeerround

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Here are my 5.1 to 2.0 mixdown coefficients.:
L R
LF 31.6% 0%
RF 0% 31.6%
C 15.9% 15.9%
LFE 15.9% 15.9%
LS 31.6% 0%
RS 0% 31.6%

31.6% = -10dB
15.9% = -16dB

That allows for a 0dB signal in all six channels without clipping, so you'll probably want to normalize after downmixing, as that is unlikely to happen so you're overall volume would be low without normalization (but guaranteed no clipping). Sony SoundForge is one good tool for these processes.
 
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