Building a multichannel system. Where and how to spend.

[Vacceo]

Hi all!

These last weeks I have been listening a lot of back and fourth discussion on speaker locations to reproduce Atmos and multichannel in general. I am wondering what is the science, studies and experience behind certain statements from different sources. Let´s see some of them.

-Gene in Audioholics considers that aside from left, center and right speakers, the most important are the ones on the sides.

His argument seems quite sound. Humans have a better sound perception to those stimuli coming to our front and sides compared to what comes to us from above or behind. Thus, Gene argues that if you have to save money on speakers, save on the rear ones for the benefit of of the front and sides. It is not stated, but I´m assuming that height speakers will provide a sound that the listener will not be able to perceive as clearly as the sound in front, so my guess is that cheaper speakers could be a fair compromise.

In an ideal world, all the speakers will be the same on all points, but we all know that this ranges from very difficult to directly impossible due to economy, space or aesthetics. Gene sounds very rational in his assesments but I´d like to know if you guys have something to add to this notion.

-There has been some controversy between the guys at Daily Hi Fi (particularly TechnoDad) and Audioholics about the location of height speakers for Atmos, DTS X and Auro 3d. The most evident notion is to set the upper speakers in the recommended configuration by Dolby to play Atmos. That is, a square around the listening spot for the upper layer angled towards the listening space and at a distance in the horizontal plane from the base layer speakers. This is the setup that the mastering in Atmos assumes on the side of the user, hence, it makes sense to replicate it as much as possible.

However, to archive a more flexible system, it is also argued that it is also possible to set an Auro-style setup with the height speakers not on (or in) the ceeling, but right above the base layer speakers if the angles are followed. With that configuration, Atmos could sound equally well. The guys in Audioholics argue that while possible, this is a substandard solution that delivers a weird sound that may or may not be to your liking, but that it is definetly not what Atmos is supposed to sound like. Due to the low amount of content in DTS X and the incredibly low amount of sources in Atmos 3D, it makes more sense to adhere to an Atmos setup as DTS X is more agnostic about speaker placement.

Ideas? Any science or experimentation you can share about all these elements?

-Most multichannel content mastered with height speakers in mind is a 7.X.4 setup. More speakers could be meaningful for larger spaces due to several rows of seats or very wide fronts, but the routing of sound will have to do more with the interpretation of the decoder than playing the source material as mastered. That means that once we pass 7.X.4, there are very clear diminishing returns. Any info about this?

I have tried to be respectful to all positions and I´m not taking sides or bashing anyone. Quite on the contrary, I am recognizing my lack of knowledge and detail on all these topics. So if Chana, Gene, Matthew or any participant in all these references reads this topic, know that I´m not critizising your ideas in any way or form, I´m bringing this up to hopefully learn a thing or two.

Since most the fellow forum participants have no vested interest on Dolby, Auro or any gear manufacturer, and we have a trove of knowledge around here, I think this forum is a good neutral ground to discuss it.

And of course, thanks for your time!

 

[Elkerton]

Vacceo,
I hope you get lots of answers (well, the correct one ). I too am interested, wanting to upgrade my 5.0 system (passive subs with high and low pass filters at mid point on opposite walls), perhaps to up-mix classical SACDs amongst other things.

 

[ooheadsoo]

I'm in the same spot, wanting to enter the multichannel space with 4 heights, but I'm unable to mount Atmos heights in the ceiling. I'm shooting for a 5.3.4 setup and debating whether or not I should set the rear heights up directly above the the side surround ala auro, or if I should try for a hybrid setup where the rear heights are above where my non existent rear surrounds would be.

 

[gene_stl]

You might consider posing the question at https://www.quadraphonicquad.com/forums/ where there is a larger concentration of people operating multichannel systems. Many of them are here too. There is a fair amount of discussion about Atmos and Auro 3D.

 

[JoachimStrobel]

For a long time I had a 5.0 system with rears being rears being slightly behind me. All speakers a floorstanders of the same type which sounds good for the Dvda and sacds with 5.0 mixes.
Now I am upgrading to Atmos. I am placing 4 heights. That is „easy“. And I am adding - sides? So my current floorstanders will then become true rears which are of less importance. But my sides will/can only be small Dali Fazon Sats. But then, listening to my 5.0 mixes, these sides become the rears and my now true rears are switched of. At least this is the way my Nad 778 does it. That leaves me pretty unhappy. It seems that a Setup for 5.0 with good speakers can not be transformed into a good 7.x.y system by simply adding small sides and delegating the old big „rears“ to „true-rears“.

 

[ooheadsoo]

For a long time I had a 5.0 system with rears being rears being slightly behind me. All speakers a floorstanders of the same type which sounds good for the Dvda and sacds with 5.0 mixes.
Now I am upgrading to Atmos. I am placing 4 heights. That is „easy“. And I am adding - sides? So my current floorstanders will then become true rears which are of less importance. But my sides will/can only be small Dali Fazon Sats. But then, listening to my 5.0 mixes, these sides become the rears and my now true rears are switched of. At least this is the way my Nad 778 does it. That leaves me pretty unhappy. It seems that a Setup for 5.0 with good speakers can not be transformed into a good 7.x.y system by simply adding small sides and delegating the old big „rears“ to „true-rears“.

What about keep your current surrounds where they are and add the new speakers as rear surrounds? Rear surround are supposed to be in the back and are relatively unimportant. The side surrounds sounds like they are probably in a decent compromise position where they already are.

 

[JoachimStrobel]

What about keep your current surrounds where they are and add the new speakers as rear surrounds? Rear surround are supposed to be in the back and are relatively unimportant. The side surrounds sounds like they are probably in a decent compromise position where they already are.

Yes, I slowly understand that. I will move the current half-rears a bit forward to the side. That looks a bit awkward as the floorstanders occupy more if the room. I always believed that in a 5.x system the rears are like in the old quadro concept. A clever switching logic in an AVR caring for different geometries between 5.x and 7.x setups and sources would be nice future feature.

 

[DavidMcRoy]

Anecdotally, I just moved to a new house. I had ceiling-mounted height speakers mounted corresponding to the recommendations for Dolby Atmos in the old house. In the new place, I fudged a slight compromise by ceiling-mounting the same height speakers (JBL LSR305, Gen I) "over" the front and back L and R speakers. The angles aren't radically different in my case, the room only being 9'X14'X17'/2.7X4.3X5.2m (HWD,) only slightly bigger than the previous room. Honestly, I find any audible difference negligible. Now, even though I'm a retired audio-for-video designer, I don't create Atmos mixes professionally, so take that with a grain of salt. There would be a little more difference in angles if the height speakers were mounted on the front and rear walls like "height/presence" speakers, though. Never tried that.

 

[Vacceo]

Yes, I slowly understand that. I will move the current half-rears a bit forward to the side. That looks a bit awkward as the floorstanders occupy more if the room. I always believed that in a 5.x system the rears are like in the old quadro concept. A clever switching logic in an AVR caring for different geometries between 5.x and 7.x setups and sources would be nice future feature.

From what I have read from Harman, human audition is not as good from the rear and above than from the front and sides (what Gene argues in the video), so the not that great speakers will be fine on the rear. Give both options a try and tell us!

Anecdotally, I just moved to a new house. I had ceiling-mounted height speakers mounted corresponding to the recommendations for Dolby Atmos in the old house. In the new place, I fudged a slight compromise by ceiling-mounting the same height speakers (JBL LSR305, Gen I) "over" the front and back L and R speakers. The angles aren't radically different in my case, the room only being 9'X13'X17' (HWD,) only slightly bigger than the previous room. Honestly, I find any audible difference negligible. Now, even though I'm a retired audio-for-video designer, I don't create Atmos mixes professionally, so take that with a grain of salt. There would be a little more difference in angles if the height speakers were mounted on the front and rear walls like "height/presence" speakers, though. Never tried that.

I was thinking something similar. If the front stage is around 2,5 meters away from the listener and the rear wall is around the same distance (relatively short room), there shouldn´t be a huge difference between a speaker located up on the wall next to the ceeling or in the ceeling itself (let´s consider a 3 meter tall room) as long as the angles are kept within spec.

 

[Adi777]

-Gene in Audioholics considers that aside from left, center and right speakers, the most important are the ones on the sides.

A lot of people say that the L and R speakers are not that important, because they are cut off at 80 Hz anyway, hmm ...

 

[Vacceo]

A lot of people say that the L and R speakers are not that important, because they are cut off at 80 Hz anyway, hmm ...

Do you mean L and R on the front or on the sides? Because crossover frequency is dependant on the capacities of the speaker. I´d see no point on crossing a tower speaker to 80hz when it is capable of going lower.

 

[Adi777]

Do you mean L and R on the front or on the sides?

Front.

 

[Vacceo]

Front.

Then my argument stands: you cross those speakers at whatever point they are able to deliver. 80 Hz is the THX standard, but depending on your speakers, it may or may not apply.

 

[ooheadsoo]

Then my argument stands: you cross those speakers at whatever point they are able to deliver. 80 Hz is the THX standard, but depending on your speakers, it may or may not apply.

Depends on how much you want to control distortion. Most full range speakers exhibit skyrocketing distortion below 100hz. I recall FToole high passed his Salon2s in his old setup. I think it also makes bass management more manageable.

 

[DavidMcRoy]

Re: 80Hz crossover: people get way too hung up on it. It isn't like a brick wall filter is completely killing all the bass going to your full range/wide range speakers. It's only a 12dB/octave slope. There's still TONS of bass energy that your main and satellite speakers are contributing to the sound. I get much better imaging, less-colored vocal sound and considerably better dynamics out of all of my speakers, including the fronts, with an 80-, 100- or 120Hz crossover. Anything else is a compromise to me. I view bigger fronts as simply capable of more dynamic range.

 

[Vacceo]

Re: 80Hz crossover: people get way too hung up on it. It isn't like a brick wall filter is completely killing all the bass going to your full range/wide range speakers. It's only a 12dB/octave slope. There's still TONS of bass energy that your main and satellite speakers are contributing to the sound. I get much better imaging, less-colored vocal sound and considerably better dynamics out of all of my speakers, including the fronts, with an 80-, 100- or 120Hz crossover. Anything else is a compromise to me. I view bigger fronts as simply capable of more dynamic range.

The factors for this or that crossover are many: room modes, extension and distortion, how loud can the speaker play, directivity...

 

[Elkerton]

Re: 80Hz crossover: people get way too hung up on it. It isn't like a brick wall filter is completely killing all the bass going to your full range/wide range speakers. It's only a 12dB/octave slope. There's still TONS of bass energy that your main and satellite speakers are contributing to the sound. I get much better imaging, less-colored vocal sound and considerably better dynamics out of all of my speakers, including the fronts, with an 80-, 100- or 120Hz crossover. Anything else is a compromise to me. I view bigger fronts as simply capable of more dynamic range.

and the ability to play louder, much louder

 

[jhaider]

In an ideal world, all the speakers will be the same on all points,

I don't think that's true, except in an psychoacoustic-aesthetic sense - if everything looks the same some brains may read "sounds the same" into that. Marketers that have managed to convince many people that a lowly toppled-MTM can be "timbre matched" to a speaker of better design because "the tweeters are the same" or some such twaddle is strong evidence for that.

However, to archive a more flexible system, it is also argued that it is also possible to set an Auro-style setup with the height speakers not on (or in) the ceeling, but right above the base layer speakers if the angles are followed. With that configuration, Atmos could sound equally well. The guys in Audioholics argue that while possible, this is a substandard solution that delivers a weird sound that may or may not be to your liking, but that it is definetly not what Atmos is supposed to sound like.

I think the Audioholics crew is wrong here. Three thoughts.

First, the Atmos "optimal" layout of a square above your damn head is basically stupid and impratical. Maybe it's fine for people who have their own little movie holes, but normal rooms used by normal people often have important functional features such as ceiling fans that are incompatible with a stupid square of speakers right over one's head. It just makes much more intuitive sense to put the heights close to in-line to the mains. Someone (Trinnov, or maybe Auro themselves) has a good paper about a "unified speaker layout." That's worth finding and digesting.

Second, most ceiling speakers suck for fidelity. That's a huge problem for immersive, and likely colors impression of different speaker arrangements. Basically if the speaker only fires straight down, ignore it on fidelity grounds. Either the baffle needs to be angled so that it can aim towards the listening position, or the midrange and tweeter (not just the tweeter!) need to be able to be angled towards the listening position. Also the same performance criteria as for every other speakers should apply - smooth directivity, flattish and smooth frequency response. That's very rare in ceiling speakers, where a tweeter-on-a-stick or toppled MTM configuration is common. So you're limited to a handful of models, most of which are expensive. (One exception is Tannoy CMS 403DC, which isn't the prettiest thing but is practical due to the gourd-shaped enclosure that can be rotated inside the mounting ring. It's a very small speaker, though, with just a 4" coax. We did fine with similar bookshelf speakers wall mounted in the old house, but I'm not sure how they'd hold up to comic book movie special effects.)

Third, personally I've not heard any notable Atmos image degradation from a setup that fits within the specs of Auro and Atmos - height speakers mounted in the ceiling roughly in line with the mains, but with V-shaped baffles to allow the midrange and treble to be aimed towards the use. Admittedly I'm not a big movie buff - truth be told I'm not sure I've sat down and watched a whole movie this decade, including during the lockdown! (Plenty of TV was binged; TV seems to be where quality story-telling has gone.) However, I listen to a lot of music in Atmos, which is a more rigorous challenge from an imaging perspective because there are no visual cues to psychoacoustically anchor sounds. I'm aware of one attempt to compare in the same room, but IMO it was flawed because the speakers used - SVS Prime Elevator - don't have particularly inspiring on axis FR and were not designed for smooth directivity (flat waveguide, etc).

 

[Vacceo]

Thanks @jhaider !

I have been giving some thought about upgrading my speakers from my old Kef IQ´s (I have been using IQ1´s angled downwards above my fronts and rears). What has cought my attention are both the Perlisten R series and the KEF R series. I like the very controlled directivity of both and the quite forgiving setup due to directivity. Another option would be using Genelec Ones. However, speaker aside, it seems like your take on speaker location aligns more with that Technodad states combined with a nice amount of REW analysis to get a clean response.

 

[Keened]

Second, most ceiling speakers suck for fidelity. That's a huge problem for immersive, and likely colors impression of different speaker arrangements. Basically if the speaker only fires straight down, ignore it on fidelity grounds. Either the baffle needs to be angled so that it can aim towards the listening position, or the midrange and tweeter (not just the tweeter!) need to be able to be angled towards the listening position. Also the same performance criteria as for every other speakers should apply - smooth directivity, flattish and smooth frequency response. That's very rare in ceiling speakers, where a tweeter-on-a-stick or toppled MTM configuration is common. So you're limited to a handful of models, most of which are expensive. (One exception is Tannoy CMS 403DC, which isn't the prettiest thing but is practical due to the gourd-shaped enclosure that can be rotated inside the mounting ring. It's a very small speaker, though, with just a 4" coax. We did fine with similar bookshelf speakers wall mounted in the old house, but I'm not sure how they'd hold up to comic book movie special effects.)

I was going to link the RSL C34E and mention that I saw they were releasing a larger successor model but it looks like it's now live so I would say that it the one to look into next.

Personally I'm considering one to use as a dedicated kitchen speaker, mount it high up on the wall and have it angled down towards the cooking area. The steep angle and distance should means decent mono sound at the stove, sink, and counter without the reflections you'd get from a smaller speaker on the counter directly.