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How do you check your channel assignment?

BeoProf

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How do you make sure the channels are hooked up correctly?
This seems like a trivial question, but please, bear with me.

Reading through the many discussion in the polls section I encountered many instances where placement of the instruments on various albums was discussed. Sometimes there were inconsistencies between the different posters, sometimes the posted placement was different from what I was hearing. The main issue seem to be the rear channels.
At first I assumed my rig is hooked up improperly, but I triple checked everything and found everything to be where it should be. In the process one encounters a natural question - how do you make sure the correct channel information is sent to the correct speaker? For instance, what if a tech working on one's vintage quad receiver swaps channels somewhere inside - how would one recognize this?

There are three ways I use with my setup:
1) enter the "speaker distance" menu on the SACD player, then it plays white noise as a test tone for each speaker, so it is easy to identify channels
2) play files with test tones for QS and SQ, that allow to identify each channel - I have these from a trusted source
3) finally, I check the placement of the instrument on the Dutton Vocalion "Boules conducts Bartok" SACD - the information about the placement of all the instrument is shown on the front cover and listed in the booklet.

When all channels are hooked up correctly all three agree and I am confident all channels are connected correctly, but still sometimes the things I am hearing are very different from what some are reporting...
Is there a good explanation?
 
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sjcorne

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...moving the conversation from the Birds Of Fire poll thread to here:

Now, assume for a second that my channel identification is correct - are there any other explanations for what people are hearing?
I can think of two examples. One would be non-identical front and rear speakers, I had such a setup for a while and it can sound unbalanced and have weird effects. Another is accidentally leaving some kind of surround processing on the receiver instead of letting all the channels from the SACD go straight through.
1. Non-identical front and rear speakers could cause balance issues, but to actually change what information is coming out of each speaker? I can't see how that's possible.
2. Like you, I'm running a vintage quad receiver - no digital processing involved in my setup. I've also verified what's in each channel by playing the discs on different systems and by ripping them and examining the waveforms on my PC.

When all channels are hooked up correctly all three agree and I am confident all channels are connected correctly, but still sometimes the things I am hearing are very different from what some are reporting...
Just checked your old posts to see what other discs you've got - I'm gonna list some examples of what I'm hearing on my setup (and PC), let me know if it's the same or different for you:

The Doors - Best Of The Doors
- On "Love Her Madly", the guitar intro is in rear left
- On "Moonlight Drive", the intro call-and-response bit jumps from front left to rear right

Herbie Hancock - Head Hunters
- On "Chameleon", the electric bass counter-melody enters from the rear right channel at around 0:40

Deodato - Prelude
- On "2001", the rear left channel is silent for the majority of the song, aside from the occasional horn part
 
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BeoProf

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The Doors - Best Of The Doors
- On "Love Her Madly", the guitar intro is in rear left
- On "Moonlight Drive", the intro call-and-response bit jumps from front left to rear right

Herbie Hancock - Head Hunters
- On "Chameleon", the electric bass counter-melody enters from the rear right channel at around 0:40

Deodato - Prelude
- On "2001", the rear left channel is silent for the majority of the song, aside from the occasional horn part
Thanks for listing these, it is great to have a reference.
So when I read your post in the morning I thought I know what the answer is, since I remembered checking one rear speaker during Deodato's 2001 intro because it seemed silent, and I remembered which one it was - it was the rear left. However, now in the afternoon I had the time to check all the disks you mentioned and the findings are quite surprising:
- my playback agrees with yours on Herbie and Deodato;
- however, on The Doors the rear channels play in reverse to what you listed, namely:
> on "Love her Madly" the guitar is in the rear right
> on "Moonlight Drive" the intro call-and-response is entirely on the left side, jumping from front left to rear left....

Now how about that???
The only thing I can think of now to explain this is that AF disks can make some SACD players or receivers decode the rear channel information differently... is that even an option?
 
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LuvMyQuad

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Thanks for listing these, it is great to have a reference.
So when I read your post in the morning I thought I know what the answer is, since I remembered checking one rear speaker during Deodato's 2001 intro because it seemed silent, and I remembered which one it was - it was the rear left. However, now in the afternoon I had the time to check all the disks you mentioned and the findings are quite surprising:
- my playback agrees with yours on Herbie and Deodato;
- however, on The Doors the rear channels play in reverse to what you listed, namely:
> on "Love her Madly" the guitar is in the rear right
> on "Moonlight Drive" the intro call-and-response is entirely on the left side, jumping from front left to rear left....

Now how about that???
The only thing I can think of now to explain this is that AF disks can make some SACD players or receivers decode the rear channel information differently... is that even an option?
Aren't you playing these using quad legacy amplification? It is common for modern AVRs to process 4.0 as stereo, but there isn't any of that going on in your system, is there? Even then, it doesn't swap the rears, it just doesn't reproduce anything in them.

That leaves only the disk player as a possibility.

Was the AF disk authored as a true 4.0 disk, or did it include silent center/LFE? Is this formatting different from the Hancock and the Dedato?
 

BeoProf

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Aren't you playing these using quad legacy amplification? It is common for modern AVRs to process 4.0 as stereo, but there isn't any of that going on in your system, is there? Even then, it doesn't swap the rears, it just doesn't reproduce anything in them.

That leaves only the disk player as a possibility.

Was the AF disk authored as a true 4.0 disk, or did it include silent center/LFE? Is this formatting different from the Hancock and the Dedato?
Yes, I am using a Sansui QRX 7001 4-channel receiver. The SACD player is feeding it via its analog outs to Tape 2. The receiver has a separate switch for "CD-4/4-channel direct" which is what I am always using for SACD playback, and I always make sure that the disc is recognized as an SACD and playing the multichannel layer.

As for SACD authoring I don't know anything about that kind of technical details for SACDs - all I can say that both of the AF discs we're discussing here (The Doors "The best of the Doors" and Mahavishnu Orchestra "Birds of Fire") have 4.0 written on the cover.
The Herbie Hancock is a Japanese Sony release and it is marked as 5.1. On the Deodato I cannot find any information about this.
I am guessing however that this does not really answer the question, since what you're asking is what is the actual situation on the disk itself, and that I don't know.

Could a different number of channels present on the disk be responsible for the situation?
 
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LuvMyQuad

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I am guessing however that this does not really answer the question, since what you're asking is what is the actual situation on the disk itself, and that I don't know.
I don't have any of the disks mentioned, so I cant answer either. Perhaps sjcorne can have a closer look at them
 

sjcorne

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Was the AF disk authored as a true 4.0 disk, or did it include silent center/LFE? Is this formatting different from the Hancock and the Dedato?
The SACD spec actually does not allow for straight 4.0 authoring. The AF discs are 5.0 (silent center, no sub) and the D-V discs are 5.1 (silent center and sub).
 

LuvMyQuad

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The SACD spec actually does not allow for straight 4.0 authoring. The AF discs are 5.0 (silent center, no sub) and the D-V discs are 5.1 (silent center and sub).
Ok so that might be the only difference, 5.0 vs 5.1. Perhaps BeoProf's disk player gets confused with 5.0 files? Hard to believe if the SACD standard is laid out in a way that allows for 5.0. Even harder to believe that the result is swapped rears.
 

BeoProf

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Ok so that might be the only difference, 5.0 vs 5.1. Perhaps BeoProf's disk player gets confused with 5.0 files? Hard to believe if the SACD standard is laid out in a way that allows for 5.0. Even harder to believe that the result is swapped rears.
If I can suggest, I am thinking that my player is actually handling the 5.0 correctly, the evidence being that when I play the AF Mahavishnu Orchestra "Birds of Fire" SACD the discussed drum roll circles around the room as it should...
 

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If I can suggest, I am thinking that my player is actually handling the 5.0 correctly, the evidence being that when I play the AF Mahavishnu Orchestra "Birds of Fire" SACD the discussed drum roll circles around the room as it should...
As I mentioned in the BoF thread, that disc was authored incorrectly with the front channels reversed. It sounds like you are hearing that already-faulty channel layout with the rears swapped as well - so the drum roll does circle, but in the wrong direction.
 

J. PUPSTER

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Yes, I am using a Sansui QRX 7001 4-channel receiver. The SACD player is feeding it via its analog outs to Tape 2. The receiver has a separate switch for "CD-4/4-channel direct" which is what I am always using for SACD playback, and I always make sure that the disc is recognized as an SACD and playing the multichannel layer.

As for SACD authoring I don't know anything about that kind of technical details for SACDs - all I can say that both of the AF discs we're discussing here (The Doors "The best of the Doors" and Mahavishnu Orchestra "Birds of Fire") have 4.0 written on the cover.
The Herbie Hancock is a Japanese Sony release and it is marked as 5.1. On the Deodato I cannot find any information about this.
I am guessing however that this does not really answer the question, since what you're asking is what is the actual situation on the disk itself, and that I don't know.

Could a different number of channels present on the disk be responsible for the situation?
I have a Sansui QRX-8001; and it sounds like your running it the same way I run mine. Is it possible that your Sansui was worked on at sometime and the analog out wiring inside on Tape 2 got moved?
Edit* - I believe mine is wired from my player into the Aux. inputs though; so try different inputs.
 

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As I mentioned in the BoF thread, that disc was authored incorrectly with the front channels reversed. It sounds like you are hearing that already-faulty channel layout with the rears swapped as well - so the drum roll does circle, but in the wrong direction.
Actually, I think it can be all explained. Bear with me :)

In the stereo version Cobham's drum set is spread across the two channels. Now move this whole drum set so that it is now spread across the rear channels. It would be logical to sit Cobham so that he is playing behind the listener, facing the listener's back. This however means, that you need to rotate the drum set 180 degrees in relation to the previous position in the front and:
1) the very minor bleed through between the front and back is mismatched
2) the drum roll won't do the circle anymore
In order to fix these two issues all you need to do is to swap the front channels.

I am thinking this is what AF did on this disc.
 

BeoProf

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I have a Sansui QRX-8001; and it sounds like your running it the same way I run mine. Is it possible that your Sansui was worked on at sometime and the analog out wiring inside on Tape 2 got moved?
Edit* - I believe mine is wired from my player into the Aux. inputs though; so try different inputs.
Don't think so, if it would get moved this would affect all disk equally, and this is happening only on some.
 

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Actually, I think it can be all explained. Bear with me :)

In the stereo version Cobham's drum set is spread across the two channels. Now move this whole drum set so that it is now spread across the rear channels. It would be logical to sit Cobham so that he is playing behind the listener, facing the listener's back. This however means, that you need to rotate the drum set 180 degrees in relation to the previous position in the front and:
1) the very minor bleed through between the front and back is mismatched
2) the drum roll won't do the circle anymore
In order to fix these two issues all you need to do is to swap the front channels.

I am thinking this is what AF did on this disc.
OK, then what about The Doors tunes? I'd still try different inputs just to be sure.
 

BeoProf

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Correct. Swapping the fronts on the AF disc matches the old SQ LP and Q8.
That's not my point at all - the above description is the explanation why the front channels on the SACD are swapped in relation to the stereo version. The placement of channels on the SACD is logically determined by the requirements of surround on this material and the fact that Cobham's drums occupy two channels, not just one. This also explains why the drum roll on the SACD goes in the other direction.
 
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sjcorne

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That's not my point - the above description is the explanation why the channels on the SACD are swapped in relation to the stereo version. The placement of channels on the SACD is logically determined by the requirements of surround on this material and the fact that Cobham's drums occupy two channels, not just one. This also explains why the drum roll on the SACD goes in the other direction.
With all due respect, you're overthinking it: AF simply made a mistake authoring their disc. I have the SQ LP and a transfer of the Q8 that confirms it. It should be violin on the left, guitar on the right, and clockwise drum roll. I concede that I may have been wrong about the layout of the stereo mix (my apologies), but I know the quad well and swapping the fronts on the AF yields the proper layout.
 

BeoProf

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With all due respect, you're overthinking it: AF simply made a mistake authoring their disc. I have the SQ LP and a transfer of the Q8 that confirms it. It should be violin on the left, guitar on the right, and clockwise drum roll. I concede that I may have been wrong about the layout of the stereo mix (my apologies), but I know the quad well and swapping the fronts on the AF yields the proper layout.
Let's agree to disagree then. As I explained above, the swapped front channels on the SACD would be the obvious consequence of the engineer paying attention to detail when remixing this material for multichannel. If the front channel assignment would be kept as in the stereo release, to match the rears Cobham would have to be playing with his back towards the listener and the rest of the band, which is not a reasonable choice (nevertheless it seems to be the choice on the Q8 at least, since the front matches stereo and the drum roll goes in a circle).

However, going back to SACD players: please correct me if I am wrong, but it seems to be a confirmed conclusion of this discussion that some of these players swap rear channels, depending on whether they are playing a 5.0 or 5.1 discs. This is quite surprising.
 
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