Rear speakers - what do they add?

[Artsfols]

I currently have a 3.1 system and am reasonably happy with it. 2 Totem Arro's left and right, an ELAC centre channel and a Totem Tribe sub. The sub has its own amp; the rest is driven by a Denon 3700 amp.
The proposal I am entertaining is to replace the Arro's with KEF LS50 Meta's then move the Arro's to alongside my back wall. The room is not big. The Arro positioning is not a concern since there's lots of advice available on how to deal with that.

My question is this. What does going to 5.1 from 3.1 add? How would you describe the difference between a 3.1 and a 5.1 system in acoustic terms? Frame of reference is stereo and various 5.1 audio sources of musical content mostly classical and indie folk, both disc, and video and audio streaming. I am not interested in movie effects.
I am also not interested in exploring purely subjective responses to this question; I would prefer a more technical explanation of the difference.

Then a secondary question to this general one is what you might think of my proposal. I am open to doing something else entirely. I will add that right now I have so much doubt about this idea that without a convincing argument otherwise, I'll just stick with what I have.
The attachment is an REW display of the response in the room at my listening position. Also, the room dimensions are 11' x 10' x 8' high, with a skylight at one side. The system and speakers are arranged along the longest wall. It's a small-ish room.

 

[DVDdoug]

If you live near an audio/video store, go and listen!

I really enjoy the surround sound in movies, and with stereo music I use a "hall" or "theater" setting for some delayed reverb in the rear and the "feel" of a bigger room. That might be good with classical (which I only listen to rarely) since the concert hall or performance hall is a big part of the live sound.

I also have a shelf-full of concert DVDs (and a few Blu-Rays) with surround.

I "only" have 5.1 and it made a BIG difference. But I don't really have a desire for more channels. My (large) rear speakers are hanging from the wall above my couch, which isn't "ideal" but they don't take-up space in the room.

 

[Robin L]

I currently have a 3.1 system and am reasonably happy with it. 2 Totem Arro's left and right, an ELAC centre channel and a Totem Tribe sub. The sub has its own amp; the rest is driven by a Denon 3700 amp.
The proposal I am entertaining is to replace the Arro's with KEF LS50 Meta's then move the Arro's to alongside my back wall. The room is not big. The Arro positioning is not my concern since there's lots of advice on how to deal with that.

My question is this. What does going to 5.1 from 3.1 add? How would you describe the difference between a 3.1 and a 5.1 system in acoustic terms? Frame of reference is stereo and various 5.1 audio sources of musical content mostly classical and indie folk, both disc, and video and audio streaming. I am not interested in movie effects.
I am also not interested in exploring purely subjective responses to this question; I would prefer a more technical explanation of the difference.

Then a secondary question to this general one is what you might think of my proposal. I am open to doing something else entirely. I will add that right now I have so much doubt about this idea that without a convincing argument otherwise, I'll just stick with what I have.
The attachment is an REW display of the response in the room at my listening position. Also, the room dimensions are 11' x 10' x 8' high, with a skylight at one side. The system and speakers are arranged along the longest wall. It's a small-ish room.

I was lucky enough to find a matched 5.0 set of speakers at a thrift store. I already had a couple of subs, previously had 5.1 systems with speakers that came from different companies. The five Infinity Primus speakers I got included two Infinity Primus 350 floorstanding speakers for the front, two Infinity Primus 250 floorstanding speakers for the back and an Infinity Primus C 25 center speaker. The sound got more coherent than the system I used with a mixture of different speakers. The 3.1 image up front was very solid, but the rear speakers in 5.1 mixes often have to reproduce wonky mixes. I didn't hear the coherence in the rear channels I could in the front. Some of my issue was probably finding a good position for those speakers in the room I was using as a "mancave". A lot of my 5.1 SACDs are of classical music. The rear channels, with few exceptions, essentially reproduce hall echo and other ambient cues. I found that really didn't contribute much. Pop/Rock recordings usually place instruments behind you. I guess that boils down to a matter of taste. The audience perspective has the musicians in the proscenium arch. But a musician's acoustic frame of reference will be in the midst of the other performers. Some 5.1 productions, Like Bob Dylan's "Love and Theft", Roxy Music's Avalon or Beck's "Sea Change" are worth it. I've found some synthetic surround mixes (presets on AVRs) work surprisingly well. Am I correct in guessing the Denon 3700 is the 9.1 AVR?

 

[Artsfols]

If you live near an audio/video store, go and listen!

I really enjoy the surround sound in movies, and with stereo music I use a "hall" or "theater" setting for some delayed reverb in the rear and the "feel" of a bigger room. That might be good with classical (which I only listen to rarely) since the concert hall or performance hall is a big part of the live sound.

I also have a shelf-full of concert DVDs (and a few Blu-Rays) with surround.

I "only" have 5.1 and it made a BIG difference. But I don't really have a desire for more channels. My (large) rear speakers are hanging from the wall above my couch, which isn't "ideal" but they don't take-up space in the room.

While we watch a number of shows and movies, they sound good enough for my taste. The centre channel was a significant improvement in understanding what people were saying on my streaming services.
I do have the same problem with not enough space for the rears, but it is solvable.
In the past, I have not liked reverb or other settings added electronically. A very subtle reverb might be okay ... but does not seem like sufficient reason to upgrade. I get quite a full sound now from the 3.1 setup that I have.
I am not trying to diminish what you are saying as clearly the change made a difference for you; I'm not sure it would translate into a difference for me. The system already sounds pretty good to my ears.

 

[Artsfols]

I was lucky enough to find a matched 5.0 set of speakers at a thrift store. I already had a couple of subs, previously had 5.1 systems with speakers that came from different companies. The five Infinity Primus speakers I got included two Infinity Primus 350 floorstanding speakers for the front, two Infinity Primus 250 floorstanding speakers for the back and an Infinity Primus C 25 center speaker. The sound got more coherent than the system I used with a mixture of different speakers. The 3.1 image up front was very solid, but the rear speakers in 5.1 mixes often have to reproduce wonky mixes. I didn't hear the coherence in the rear channels I could in the front. Some of my issue was probably finding a good position for those speakers in the room I was using as a "mancave". A lot of my 5.1 SACDs are of classical music. The rear channels, with few exceptions, essentially reproduce hall echo and other ambient cues. I found that really didn't contribute much. Pop/Rock recordings usually place instruments behind you. I guess that boils down to a matter of taste. The audience perspective has the musicians in the proscenium arch. But a musician's acoustic frame of reference will be in the midst of the other performers. Some 5.1 productions, Like Bob Dylan's "Love and Theft", Roxy Music's Avalon or Beck's "Sea Change" are worth it. I've found some synthetic surround mixes (presets on AVRs) work surprisingly well. Am I correct in guessing the Denon 3700 is the 9.1 AVR?

Avalon is a great record. I attend a large number of live performances, so anything with the instruments placed behind me ... I don't know. Mind you, on vacation last year, I ended up sitting in a club in Edinburgh in the middle of the performers. It was pleasant, with the sound all around us. On a humorous note, the bartender had sent us (my son and I) there as it was the only seating left in the place. It was a semi- open mic affair, and the host/emcee seemed to think I was up there to sing. I was up for it, but my son begged him not to let me do it. Perhaps that was for the best. My hidden possibilities as a singer remain untapped as of yet.
The idea of sound mixed explicitly for 4 distinct aural channels is intriguing, but how often is that done? I had a 4 speaker channel setup in the 1970s, but that was mainly for rock music, and the idea was just to obtain a higher volume of sound. Great for parties when I was into that. And I did have a buddy with a decent quadrophonic setup and an extensive quadrophonic collection. But that was then.

 

[kyuu]

This seems like a trick question. Surrounds add the ability to have sounds originate to your sides and behind you.

 

[Robin L]

The idea of sound mixed explicitly for 4 distinct aural channels is intriguing, but how often is that done? I had a 4 speaker channel setup in the 1970s, but that was mainly for rock music, and the idea was just to obtain a higher volume of sound. Great for parties when I was into that. And I did have a buddy with a decent quadrophonic setup and an extensive quadrophonic collection. But that was then.

SACDs are the best format for 5.1 sound. Note that 5.1 means 5 distinct channels. Of course, front and center is a lot like phantom center. While SACDs really didn't take off in pop music (thought it does alright in Jazz) lots of multichannel mixes sort out into something close to the sound of a 5.1 mix. And if your amp is a multi-channel AVR, I would think that would be the way to go.

 

[Artsfols]

This seems like a trick question. Surrounds add the ability to have sounds originate to your sides and behind you.

The question is - given the audio sources I use, and the proposed setup, how would the aural experience change for the better.

If someone asked me if they should upgrade from 2.0 (with Totem Arros) to 3.1, I would answer something like this. The Arros put out clean bass, and on classical sources, a sub will not add much. On indie folk, a sub will be significant, but make sure you buy a high quality sub, and have an amp that allows you to set the crossover. You'll get more volume out of the Arro's and thus, out of the system as a whole, because the woofers will have less work to do. The centre channel should not be used for your stereo sources as it will screw with the imaging. However, for video streaming (Netflix, Disney, etc.) dialogue will be much clearer coming through the centre channel.
For pop and rock records that are not compressed and have a multi-channel audio track with decent dynamics (i.e. Eric Clapton's Crossroads), you will have a much fuller sound experience and the dynamics will be increased. Some orchestral classical CDs will also have much fuller forte's and crescendo's.

So if I add the rears what would be the equivalent description?

 

[GD Fan]

For years all I listened to was upmixed 5.1 multi-channel music from CDs. The past few years I've only listened to the intended stereo replay. And, for me, 2.1 isn't as good.

My SACDs and Blu Ray audio, as well as TV & movies, still play in 5.1 and to me that's outstanding.

For background and a technical look at the subject check out chapter 15 of Sound Reproduction by Floyd Toole.

 

[Artsfols]

SACDs are the best format for 5.1 sound. Note that 5.1 means 5 distinct channels. Of course, front and center is a lot like phantom center. While SACDs really didn't take off in pop music (thought it does alright in Jazz) lots of multichannel mixes sort out into something close to the sound of a 5.1 mix. And if your amp is a multi-channel AVR, I would think that would be the way to go.

For years all I listened to was upmixed 5.1 multi-channel music from CDs. The past few years I've only listened to the intended stereo replay. And, for me, 2.1 isn't as good.

My SACDs and Blu Ray audio, as well as TV & movies, still play in 5.1 and to me that's outstanding.

For background and a technical look at the subject check out chapter 15 of Sound Reproduction by Floyd Toole.

Is it a question of imaging being improved in a 5.1 mix? A good stereo mix fools the ear into spreading the instruments across a soundstage, and the speakers literally disappear. That is what happens with my current setup, and why I do not use the centre channel with stereo sources.
It strikes me that a 4 or 5 channel mix could even go one step further. Is that the difference? Also, I don't have Floyd Toole's book. Keep in mind I am more concerned with what happens than how it happens.

 

[Chrispy]

In a 5.1 you first get surrounds, takes 7.1 to get "rears". FWIW.

 

[Artsfols]

In a 5.1 you first get surrounds, takes 7.1 to get "rears". FWIW.

Thanks for the clarification.
It strikes me that before there were 7.1s, i.e. 4.0 and later 5.1, they were called rear speakers.
But when you play a 7.1 mix through a 5.1 setup, does it play the rear track(s), the surround track(s), or some composite of the two?

 

[Chrispy]

Thanks for the clarification.
It strikes me that before there were 7.1s, i.e. 4.0 and later 5.1, they were called rear speakers.
But when you play a 7.1 mix through a 5.1 setup, does it play the rear track(s), the surround track(s), or some composite of the two?

Quad (4.0) was a bit different, more intended as more or less equal channels (usually for same speakers as fronts as well), and arranged differently. Yeah, some early 5.1 stuff did call them rears but in use the surrounds are set more to the sides rather than rear. Look up Dolby speaker placement guidelines perhaps.

As to the 7.1 mix, most gear will know if you have 7.1 or 5.1 and will either use an available 5.1 mix or core, or downmix the 7.1 to 5.1.

 

[GD Fan]

Is it a question of imaging being improved in a 5.1 mix? A good stereo mix fools the ear into spreading the instruments across a soundstage, and the speakers literally disappear. That is what happens with my current setup, and why I do not use the centre channel with stereo sources.
It strikes me that a 4 or 5 channel mix could even go one step further. Is that the difference? Also, I don't have Floyd Toole's book. Keep in mind I am more concerned with what happens than how it happens.

I guess I'd say, as a purely personal and subjective impression which is therefore to be considered strictly as such, that 5.1 is more enveloping while 2.1 may better allow for that sound stage that you're familiar with - the stereo sound stage always strikes me as spacially in front of me. So both have their place and their benefits. When music is mixed for 5.1 (lots of Dire Straits and Pink Floyd, probably others as well) it is an awesome experience.

 

[kyuu]

I think the best way to see for yourself what it offers is to do a temporary setup and get a good multichannel source. There's a lot of good multichannel classical releases. For something more pop/rock, I might recommend Peter Garbriel's I/O. Great album, and excellent multichannel mix.

 

[Artsfols]

So what I'm getting is that 5.1 mixes are distinctly different from 2.0 mixes. I am curious as to what is different about the mix, but I don't disbelieve that in some cases, it will offer a better listening experience.
A good stereo mix can be awesome compared to a poor one. Stereo mixes can sound flat and lifeless on one hand, or crisp and exciting on the other.
So with more channels, there is scope to improve the mix even further.
It does strike me now that this is worth doing. So the question reduces to whether the proposed speaker configuration is workable.
I am of the mind that if speakers are accurate, brand does not really matter.
For example, my ELAC centre channel does fine with my Totem speakers when I play a 5.1 mix through it.

 

[Artsfols]

Quad (4.0) was a bit different, more intended as more or less equal channels (usually for same speakers as fronts as well), and arranged differently. Yeah, some early 5.1 stuff did call them rears but in use the surrounds are set more to the sides rather than rear. Look up Dolby speaker placement guidelines perhaps.

As to the 7.1 mix, most gear will know if you have 7.1 or 5.1 and will either use an available 5.1 mix or core, or downmix the 7.1 to 5.1.

Does it downmix? Or does it just drop 2 of the channels, and if so, which?

I'm pretty sure when playing multi-track through my 3.1 system the AVR just drops the rears and surrounds.

 

[Robin L]

Does it downmix? Or does it just drop 2 of the channels, and if so, which?

I'm pretty sure when playing multi-track through my 3.1 system the AVR just drops the rears and surrounds.

Center and sub.

 

[Artsfols]

Center and sub.

The question is - when playing a 7.1 mix through a 5.1 system, what does the AVR do?
There are 3 possibilities that I see: drop the rears, drop the surrounds, or mix rears and surrounds in some way.

 

[boxerfan88]

My question is this. What does going to 5.1 from 3.1 add? How would you describe the difference between a 3.1 and a 5.1 system in acoustic terms? Frame of reference is stereo and various 5.1 audio sources of musical content mostly classical and indie folk, both disc, and video and audio streaming.

Difference between 5.1 vs 2.1:
1. Sound envelopment from venue ambience/echoes, audience claps and noises coming out of the side speakers. (Live content)

2. 3D effects from side speakers if studio music content is engineered/mixed by someone.

That’s pretty much it, in my opinion. I enjoyed it for a short period and moved back to 2.1 for music; and used 5.1 primarily for movies.