Quad in a 7.1 (or 7.1.2 or 7.1.4) system

[ProgRules]

When playing a 4.0 source in a 7.1 system with no processing/upmixing, do the rear channels come from the side surrounds, rear surrounds or both?

It seems to me that the rear signals coming from the rear surrounds would be more like a true quad setup. I have a 5.1.4 setup which going by Dolby recommendations has the surrounds at about 100 degrees (ie slightly behind the MLP). This is obviously not the 4 corner quad setup. I would consider moving to a 7.1 bed if quad plays out of the rear surrounds, though tha's a little problematic. I'd need an amp to drive the rears (would just use an old AVR, so no big deal), but I don't have much room for proper speaker placement behing the sofa where the MLP is.

My room is also far from ideal, being a living room with most of one side open to the hallway, along with a few other non-standard features that detract from acoustics.

 

[SeeMoreDigital]

When playing a 4.0 source in a 7.1 system with no processing/upmixing, do the rear channels come from the side surrounds, rear surrounds or both?

Technically, discrete 4-channel (quad) encoded audio should come from just the sides, not the rears or a combination of both.

For those of us with 7.1 channel set-ups listening to quad properly is a compromise due to our side speaker placements, 'ideally' they should be further back (and the rear speakers should match the front speakers in both make and model) but how many of us are going to reposition our side speakers every time we play a quad mix.

Also, some AVR's matrix the audio from the side surrounds to the rear surrounds too which is just plain wrong!

 

[ProgRules]

Technically, discrete 4-channel (quad) encoded audio should come from just the sides, not the rears or a combination of both.

For those of us with 7.1 channel set-ups listening to quad properly is a compromise due to our side speaker placements, 'ideally' they should be further back (and the rear speakers should match the front speakers in both make and model) but how many of us are going to reposition our side speakers every time we play a quad mix.

Also, some AVR's matrix the audio from the side surrounds to the rear surrounds too which is just plain wrong!

Thanks for the info. So adding rear surrounds wouldn't change what I hear in 4.0. Unless my Pioneer matrixes the sound back there, which still isn't right.

 

[LuvMyQuad]

I like Quad rears coming from the sides.

 

[ProgRules]

I like Quad rears coming from the sides.

You prefer it to the conventional quad speaker arrangement? I've never had a true quad setup (1 each in 4 corners), but I always figured it was the best way to hear quad.

 

[AYanguas]

In my Denon , and I guess in most AVR, the 4.0 mch, or 5.1 with Center and LFE silent, have the rears always output to the Side Surrounds in a 7.1 system.

The Rear channel content is only "duplicated" to both Side Surrounds and Surround Backs in a 7.1 system when decoding DTS 5.1/4.0

For some mixes, the Quad playback with the rear channels going to the Side Surround Speakers can be pleasant and you may get a binaural "into your head" feeling when the Sides are located at 90-100º

But, generally, this cause a big volume presence from the Quad rears that 'hides' the front stage. It can be tuned a bit by lowering the volume level on the Side Surrounds.

The best way in a 7.1 system is to have the Quad Rear channels output to the Surround Back speakers, which locations are nearer to you beeing in the center of the Speakers Square for Quad.

This can be done in several ways:

1) Recabling or implement speaker switches.
It's a bit cumbersome.

2) Custom Speakers assign, if the AVR supports that. My DENON 8500 supports that.
Not bad, but you have to "reconfigure" the AVR, or load a different config from the USB stick. (And check if different room conditioning settings are still valid).
I think some newer AVR implement two "in memory" configs that can be switched.

3) There is the option in the MMH tool: "Remix Audio Channels / Move Quad Sides to Backs (Remix Quad to a 7.1 format file"
If you have a player that can play well the 7.1 mch file this could be the better solution it you have the Quad ripped mch files.

 

[barfle]

The room I have now is the first where I’ve had the space to actually put the rear speakers fully behind all the listening positions. My previous setups had a sofa against the back wall with the back speakers pretty much in line with the listeners’ ears.

All the information I had read about quad, going back to 1973 or so, indicated that the listener should be in the middle of a square of four identical sound sources for optimum sonics. I don’t have that, and probably never will, but what I have is pretty good.

My system is 5.1, and the digital stuff seems to decode properly through my Oppo 105. I doubt that I will do 7.1, although Atmos is in the plans.

 

[LuvMyQuad]

You prefer it to the conventional quad speaker arrangement?

Yes. Discrete sound coming from behind is too unnatural for me.

 

[ProgRules]

In my Denon , and I guess in most AVR, the 4.0 mch, or 5.1 with Center and LFE silent, have the rears always output to the Side Surrounds in a 7.1 system.

The Rear channel content is only "duplicated" to both Side Surrounds and Surround Backs in a 7.1 system when decoding DTS 5.1/4.0

For some mixes, the Quad playback with the rear channels going to the Side Surround Speakers can be pleasant and you may get a binaural "into your head" feeling when the Sides are located at 90-100º

But, generally, this cause a big volume presence from the Quad rears that 'hides' the front stage. It can be tuned a bit by lowering the volume level on the Side Surrounds.

The best way in a 7.1 system is to have the Quad Rear channels output to the Surround Back speakers, which locations are nearer to you beeing in the center of the Speakers Square for Quad.

This can be done in several ways:

1) Recabling or implement speaker switches.
It's a bit cumbersome.

2) Custom Speakers assign, if the AVR supports that. My DENON 8500 supports that.
Not bad, but you have to "reconfigure" the AVR, or load a different config from the USB stick. (And check if different room conditioning settings are still valid).
I think some newer AVR implement two "in memory" configs that can be switched.

3) There is the option in the MMH tool: "Remix Audio Channels / Move Quad Sides to Backs (Remix Quad to a 7.1 format file"
If you have a player that can play well the 7.1 mch file this could be the better solution it you have the Quad ripped mch files.

Thanks. That's great info.

As for quad coming from the sides, the impetus for this thread came from my experience listening to the quad of Miles of Aisles. It is a great experience, but Joni's voice seemed to come either right in front of me or even right over my head. In a way it was kind of cool, but I couldn't help but think that her voice should be coming from the middle of the room and having the rear channels to my sides was pulling it back more than it would be in a true four corner setup. Your explanation fits with what I experienced and what I was thinking.

And that's why I was wondering if I moved to a 7.1 channel bed if the rears would play in the rear surrounds. Why aren't AVR's made like that? Because they're focused on movie sound and multichannel music is an afterthought???

 

[ProgRules]

Yes. Discrete sound coming from behind is too unnatural for me.

As I've never experienced a four corner setup, can't say if I'd find it unnatural or not. But as I stated above, having the rears come from the sides doesn't sound exactly right. Though certainly not unpleasant.

 

[DrKlahn]

Placement and your speakers will enter into it. My older 5.1 setup that I played SACD/DVDA was basically how you would want a Quad setup with the 2 rears in more of a corner configuration. My 7.1 setup has channels 4/5 slightly behind and angled towards the sweet spot. Because of the dispersion characteristics of the speakers they don't have any issues being further forward and almost to the sides. They can convincingly image behind your head. Of course it helps that the current speakers are a lot better than the old setup was.

 

[SeeMoreDigital]

As I've never experienced a four corner setup, can't say if I'd find it unnatural or not. But as I stated above, having the rears come from the sides doesn't sound exactly right. Though certainly not unpleasant.

I guess it depends on where people's journey into surround sound started...

My journey started with quad using matched speakers equally spaced near corners. When I moved up to 5.1 (5-channels in reality as I didn't want a sub/lfe) primarily to hear Dolby Surround movies I bought the required processors and a powered centre speaker to accommodate it.

When surround audio gear went fully digital I bought a dedicated AVR a set of smaller speakers and stupidly sold the pair of speakers I'd been using for quad along with the quad amplifier/receiver!

Perhaps when I move house I'll be able to create a dedicated music listening room with at least four matching speakers so I can listen to quad correctly again

 

[DrKlahn]

I guess it depends on where people's journey into surround sound started...

My journey started with quad using matched speakers equally spaced near corners. When I moved up to 5.1 (5-channels in reality as I didn't want a sub/lfe) primarily to hear Dolby Surround movies I bought the required processors and a powered centre speaker to accommodate it.

When surround audio gear went fully digital I bought a dedicated AVR a set of smaller speakers and stupidly sold the pair of speakers I'd been using for quad along with the quad amplifier/receiver!

Perhaps when I move house I'll be able to create a dedicated music listening room with at least four matching speakers so I can listen to quad correctly again

I will say if you get a pair of capable rears that timbre match well, you don't have to get identical speakers. It wouldn't be practical in my case to put the same towers that are my L/R in the 4/5 location. But other than the rear channel extension not going as low (I cross them over at 60Hz), the voicing is spot on. Naturally if the room can handle all 4 being the same, no reason not to go that route.

 

[AYanguas]

Why aren't AVR's made like that? Because they're focused on movie sound and multichannel music is an afterthought???

IMO, the Home Theater systems started with 5.1, and it was no doubt that for a 4.0 content or 5.1 content the rear channel content goes to the 'only' existing rears.

Then it came the addition of the Surrounds Back, to complete the rear stage by "adding" the Surrounds Back speakers for the 7.1 (No mention to the 6.1 with a single rear channel).

As the additional surround backs (over 5.1) are that, "additional", current mch 5.1 files, where a Quad mix is provided, continue to output to the same Surround Channels as before. The surrounds, now called "Sides" to differentiate from the Rears or, now, Surround Backs.

DTS would adress this situation and try to "image" the rear content from 5.1/4.0 in a similar location as with the first 5.1 systems, with the surrounds more "back" and not as "side". Then it activates both surrounds pairs for that purpose. Even decreasing the volume level a little to have same overall volume level with the double of speakers, I think.

Yes. Discrete sound coming from behind is too unnatural for me.

The "binaural" good effect coming from Sides at 90-100º not only behaves like "into my head", but also you may feel that the sound is coming from above, even no cealing speaker is engaged.

Once I get used to that, when I listen Quad mixes in this way, it looks that I like more, but the problem, as I said above, is that the Front Stage sound appears "lowered" and the global result is not well balanced.

Then, when I change to 7.1 with Quad to Surround Backs, Yes, the volume level is balanced, but I loose that good binaural feeling..

For Quad, the Rears coming from behind, although it should be "as the mixer intended", result in a less spectacular rear sound stage than with Sides.

But with Atmos, when different discrete content is used for Sides and Surround backs, the effect is really amazing. The 'unnatural" sound coming from behind, is so unnatural that makes the overall mix so spectacular and amazing.

I will say if you get a pair of capable rears that timbre match well, you don't have to get identical speakers. It wouldn't be practical in my case to put the same towers that are my L/R in the 4/5 location. But other than the rear channel extension not going as low (I cross them over at 60Hz), the voicing is spot on. Naturally if the room can handle all 4 being the same, no reason not to go that route.

The hearing human perception is less for sounds coming from behind than for sounds coming from the front. So, a lower quality level than the front towers, could be enough, if budget or room possibilities are a compromise. But the timbre match (for example, same series manufacturer, but lower level), I think is important to keep the nature of the same sound when moving/panning or circling around you. Both for films and for music.

 

[MidiMagic]

Why aren't AVR's made like that? Because they're focused on movie sound and multichannel music is an afterthought???

Because Dolby wants people to abandon all quad and matrix systems (including his own now out of patent protection) and buy only his new patent-protected Atmos. Planned obsolescence.

Actually, I want to hear my old matrix recordings more than I want to hear anything discrete. I am thinking of doing both.

I am in the process of building a system with multiple stereo amplifiers to feed the speakers and switchboxes to select which sources go to which speakers. Since the quad sources are separate from the 7.1 sources, they could be wired as needed to the switchboxes..

The different quad systems work better with different speaker layouts.
- To keep discrete from cogging, the back speakers must be to the sides instead of behind the listener.
- Dolby Surround and the Hafler diamond do not cog and work best with the listener in the center.
- Other matrix systems need various treatments.

 

[SeeMoreDigital]

I am in the process of building a system with multiple stereo amplifiers to feed the speakers and switchboxes to select which sources go to which speakers. Since the quad sources are separate from the 7.1 sources, they could be wired as needed to the switchboxes..

Nice to hear

 

[armyjazzer]

You prefer it to the conventional quad speaker arrangement? I've never had a true quad setup (1 each in 4 corners), but I always figured it was the best way to hear quad.

There seems to be differing opinions:

https://www.wendycarlos.com/surround/surround.html

I have been trying to sort this out for a long time. Do some experimenting and see what you like best.

Right now I have finally got my new 5.1 speaker setup completed and I am testing out having the fronts and center channels placed like traditional 5.1, but my rears placed like the surround master manual recommends for Quad rears. So far great with 5.1 and a few Quads that I have listened to. I'm not sure what changes will be needed when I expand to Atmos height speakers also, but so far even Atmos content I have played on the 5.1 setup sounds good.

 

[barturtle]

In my Denon , and I guess in most AVR, the 4.0 mch, or 5.1 with Center and LFE silent, have the rears always output to the Side Surrounds in a 7.1 system.

The Rear channel content is only "duplicated" to both Side Surrounds and Surround Backs in a 7.1 system when decoding DTS 5.1/4.0

Interestingly, Onkyo (at least the TX-RZ70, but I'll assume their other 7.1.4 capable are the same) when 4.1/5.1 Dolby digital, which is what I think Rhino is using on their Quadio Blu-ray, rear info comes from surround back speaker, but DSD uses the sides.

 

[quicksrt]

As I've never experienced a four corner setup, can't say if I'd find it unnatural or not. But as I stated above, having the rears come from the sides doesn't sound exactly right. Though certainly not unpleasant.

Rears coming from the sides is too close to the fronts for me. I want harder stronger separation, and having a four-corner square keeps thing separate if the mixer wanted it that way.

 

[quicksrt]

Interestingly, Onkyo (at least the TX-RZ70, but I'll assume their other 7.1.4 capable are the same) when 4.1/5.1 Dolby digital, which is what I think Rhino is using on their Quadio Blu-ray, rear info comes from surround back speaker, but DSD uses the sides.

This is interesting and needs more investigation. I want my rear speakers to be in the rear / back of the square room. We'll have to compare an AF "Full Sail" with a Quadio "AWB" and a DV EW&F and see if this is true.