Small room surrounds: single vs array?

[efzauner]

My HT room build is progressing.

The main sitting area is 12 x 17ft and will have a sectional sofa filling the area. Above the area is a soffit all around. So the surround speakers will have to be mounted on the wall, up against the soffits. The plan is to make custom wedge surrounds and rears that aim diagonally down to the listeners.  But for all seating positions, either the surrounds or the rears will be almost directly overhead. 

Question: Would single "point" source surrounds and rear be best or would an array of say 4 full range speakers spanning 4-6 feet long be best for a more dispersed sound? 

 

In addition. there is a 3 foot wide hallway along the long side, making the room actually 15x17.  I don't want to mount a dipole under the soffit because it will be sticking down between the 12 foot wide section and the 3 foot wide hallway.  

Difficult to decide.  

 

thanks

 

 

[Chris A]

Question: Would single "point" source surrounds and rear be best or would an array of say 4 full range speakers spanning 4-6 feet long be best for a more dispersed sound?

 

The choice is really between point sound localization (sound effects only) and "listener envelopment" (LEV) for surround sound like music and ambient sounds, as it turns out.  The following figure will give you some idea of the contribution to the surround sound effect vs. position of loudspeakers.  I think that you'll find that the loudspeakers located far behind the listeners aren't very effective, in fact, they detract from the listening experience:

 

 

So placing surrounds becomes a trade-off between sound localization and "immersion".  Since immersion is the dominant effect for movies (percentage of listener's time) I'd think about placing the surrounds for best envelopment and for "timbre matching", which is a function of the coverage angles of the full-range channels and their frequency response relative to each other.  So if you use a loudspeaker surround type that is much wider than the fronts, you'll never get the timbres to match.  That's saying that point source and matching the coverage angles of the front three loudspeakers is actually important.

 

However, there is another group of people that believe that just being able to splash around sound in the room from the back surrounds is good enough. 

 

Since I listen to music recordings that localize music to each surround channel, I try to match timbres.

 

Chris

[Youthman]

I had a similar issue and Wakejunkie built me some custom angled mounts for my surround back

https://community.klipsch.com/index.php?/topic/146688-custom-mounts-for-my-rs-62ii-designed-by-wake-junkie/

[Chris A]

Having the surround channels at approximately the same height (usually slightly higher) than the fronts is also a recommendation from Dolby and THX. 

 

I find that there is a coupling between the coverage angles, frequency response of the surrounds, their horizontal locations around the listeners, and also their height above listener's ears.  I try to keep the surround midrange horns within 2 feet of the same height of the listener's heads, based on those experiences.  Otherwise, you wind up with a "HT only" system that doesn't play surround sound music very well.

 

YMMV.

 

Chris

[Zen Traveler]

I think that you'll find that the loudspeakers located far behind the listeners aren't very effective, in fact, they detract from the listening experience:

 

I realize the question involved using two sets of surround speakers in a small room but I find using a set of side surrounds parallel with the MLP and a set of rear speakers (connected to the Rear and not Surrounds)   works great/better than a single set of surrounds. I also listen mostly to Multichannel music and for both it and movies use the Dolby PLIIz (heights as well) feature which matrixes the side surrounds with the rears and there is a more enveloping sound with some 5.1 music seemingly having a discrete  rear channel--Talking Heads music REALLY sounds good on our Home Theater (listed below).

[derrickdj1]

My HT room build is progressing.

The main sitting area is 12 x 17ft and will have a sectional sofa filling the area. Above the area is a soffit all around. So the surround speakers will have to be mounted on the wall, up against the soffits. The plan is to make custom wedge surrounds and rears that aim diagonally down to the listeners.  But for all seating positions, either the surrounds or the rears will be almost directly overhead. 

Question: Would single "point" source surrounds and rear be best or would an array of say 4 full range speakers spanning 4-6 feet long be best for a more dispersed sound? 

 

In addition. there is a 3 foot wide hallway along the long side, making the room actually 15x17.  I don't want to mount a dipole under the soffit because it will be sticking down between the 12 foot wide section and the 3 foot wide hallway.  

Difficult to decide.  

 

thanks

 

A pic of the room would really help with suggestions.  The RS speakers do a good job with point source and immersion for a HT/music system.  I just flush mount the RS speakers, angling will make the point source input a little much for me.

[Chris A]

I also listen mostly to multichannel music and for both it and movies use the Dolby PLIIz (heights as well) feature which matrixes the side surrounds with the rears and there is a more enveloping sound with some 5.1 music seemingly having a discrete rear channel

 

The figure provided above was from a paper where the researchers were using 24 surround loudspeakers in a ITU "standard room", then using combinations of surrounds shown in the individual columns.  The listeners were not told which loudspeakers were on and which ones weren't. 

 

What the data says from that experiment is that you don't need 24 loudspeakers to approximate the sound experience.  In fact 5 surround channels do very well, indeed.  Perhaps the acoustics of your room differs from the ITU "standard room".  I've found that having a room that's about 40' deep is much better in terms of listener envelopment than having rear surrounds...so I don't use them, and I put the surrounds at about 80 degrees from the front centerline of loudspeakers so that the chairs we sit in don't interfere with the direct sound arrival.  That has worked best for my listening room--by far.  The plot above also bears that out.

 

Chris

Edited February 22, 2016 by Chris A

[Zen Traveler]

What the data says from that experiment is that you don't need 24 loudspeakers to approximate the sound experience. In fact 5 surround channels do very well, indeed. Perhaps the acoustics of your room differs from the ITU "standard room. I've found that having a room that's about 40' deep is much better in terms of listener envelopment than having rear surrounds

 

Agreed that every room is different and our room isn't 40' deep. I also think using the Dolby PLIIz processing adds to the experience verses just considering the speakers in less than ideal situations...of course, some rooms already have suitable dimensions and speaker placement is easier done. We also have 2 HTs where we use the RS speakers in a 5.1 configuration and they work well for those purposes, but in our main HT and using the process described it does seem like we have a separate rear sound field on some material and the sound goes from the side surrounds to the rear on quite a few 5.1 Music disks, which is where I notice it most.

[Chris A]

Yes...and the loudspeakers themselves (coverage angles and their frequency response) seem to make a huge difference.

 

For instance, the Jubs in the front corners of the room (about +/- 34 degrees from centerline at the listening position) are much more enveloping due to the nature of the K-402 horns--basically the whole front wall plus some of the side walls become one radiating image.  The surround Cornwalls perform adequately as surrounds due to their position horizontally and at head level.  If I were using surround bipoles (as you apparently do), I'd have to change the surround locations (height and horizontal angle) fairly significantly. 

 

Bottom line: it's a bit more complicated than just using one factor (horizontal angle) or another (vertical angle from the listener's head), and includes the loudspeaker types, room acoustics, listening positions within the room, and what you're trying to achieve, unfortunately. 

 

Some of this discussion is based on guessing what the OP has in all those areas and what he's trying to achieve.  Perhaps a little more information may be useful in answering his basic question.

 

Chris

Edited February 22, 2016 by Chris A

[Zen Traveler]

For instance, the Jubs are in the front corners of the room (about +/- 34 degrees from centerline at the listening position) is much more enveloping due to the nature of the K-402 horns--basically the whole front wall plus some of the side walls become one radiating image. The surround Cornwalls perform adequately as surrounds due to their position horizontally and at head level. If I were using bipoles (as you apparently do), I'd have to change the surround locations (height and horizontal angle) fairly significantly.

 

I have heard there is no better listening experience than what happens in the room you describe above. That said, no I use RB-75s for both rear and surrounds and have found the direct sound coming from 4 speakers using Dolby PLIIz (and even the basic matrixing of prior Denon AVR models) than 2 speakers at either location whose horns are pointing away a better sound experience. Another factor is that we sit within 4 ft of our surrounds and are lucky enough to have the rears at about 8' back....{EDIT Note: We have also used/tried RS-7s/3s as side and rear surrounds in a 5.1 configuration over the years and it also sounded great, but if I had a choice--I'd do what we do.}

 

Fwiw, it appears that Dolby Surround on Atmos AVRs use similar principles converting legacy (5.1) material and using the other speakers--I haven't kept up with that in the last several months but prior folks were commenting that it was a feature that enhanced their listening experience.  

Edited February 22, 2016 by Zen Traveler

[efzauner]

Thanks for the info... but I have no leeway on height...  The R L surrounds and the 2 rears MUST be on the wall up against the soffits.  So about 7ft high.

For all purposes imagine a sectional sofa that is 12 feet wide with seating area against the walls on all 3 sides.  Thus the surround speakers are right above the seating area.

I don't have the option of placing at a distance...  Will draw a figure later tonight. Pictures wont do,  concrete and 2x4s only at this time.

 

Center is KLF C7  Maybe 2! one below screen and one above screen.

Mains either Tangent 400 or KLF-20

Surrounds.. none right now except for KG4 tweeters and Eminence Alpha 8s and generic crossovers that I can built into 4 wedge surrounds.

This will be mainly for HT as I do not have much in terms of 5 channel music recordings. For music I will just go Stereo.

I wont have room for any sort of Klipsch surround.  Just too big. Will hit your head on them.

Edited February 22, 2016 by efzauner

[efzauner]

I had a similar issue and Wakejunkie built me some custom angled mounts for my surround back

https://community.klipsch.com/index.php?/topic/146688-custom-mounts-for-my-rs-62ii-designed-by-wake-junkie/

 

Gorgeous but you  have 3 feet more height and 2 feet more side room.  Imagine the walls touching the seats on either side and the back of the seat against the rear wall!

[RoboKlipsch]

I have bookshelf speakers mounted on the wall 7ft above and 90-95 degrees from center and they sound absolutely great.  Lower is NOT necessarily better.  I mounted the bookshelves upside down to lower the tweeters a bit.  The back surrounds DO need to point down from that height (mine start at 6') because to hear the sweep of surround you need to have the backs pointing to just above the listener position (imo).  What happens if they are too high is you simply don't hear it properly...it's back there but it doesn't have any location at all.  

 

Before mounting I tried every height between ear level and the ceiling (using a ladder, boxes, etc.).  Yes, at ear level you hear them but assuming your space is not wide, they are too close, and distracting.  But as you move up (I think probably 6' or so is likely ideal), they don't fade like you might expect.  I didn't want anybody hitting their head on the speakers so 7" was good...and one is above a doorway and required it.  I've tilted them down 7 degrees, but it's not necessary.   

[RoboKlipsch]

 

I also listen mostly to multichannel music and for both it and movies use the Dolby PLIIz (heights as well) feature which matrixes the side surrounds with the rears and there is a more enveloping sound with some 5.1 music seemingly having a discrete rear channel

 

The figure provided above was from a paper where the researchers were using 24 surround loudspeakers in a ITU "standard room", then using combinations of surrounds shown in the individual columns.  The listeners were not told which loudspeakers were on and which ones weren't. 

 

What the data says from that experiment is that you don't need 24 loudspeakers to approximate the sound experience.  In fact 5 surround channels do very well, indeed.  Perhaps the acoustics of your room differs from the ITU "standard room".  I've found that having a room that's about 40' deep is much better in terms of listener envelopment than having rear surrounds...so I don't use them, and I put the surrounds at about 80 degrees from the front centerline of loudspeakers so that the chairs we sit in don't interfere with the direct sound arrival.  That has worked best for my listening room--by far.  The plot above also bears that out.

 

Chris

 

 

First let me say that Chris' post above this that shows the study of speaker positions....that's the s***!  Few that I've seen have a definitive grasp of what works, how well, and what you lose if you do something different.  That chart says just about everything about basic placement.

 

If you read closely to what he wrote above...he is saying that his surrounds are NOT at 90 degrees or more...meaning they are not behind the seating position or even with it.  They are slightly in front.  And the study he posted shows that from maybe 60 degrees up until 120 degrees you get a great room response.

 

So there is your answer....you can put the surrounds in a 5.1 setup IN FRONT of the seating position, and still achieve great surround, perhaps ideal.  The question you should pose to Chris and the others then is what speakers will do best in THAT situation...where the sidewalls and backs are at the seating position.  Bookshelves?  I'm guessing an RS or RP surround would be incredible.  I'm a newbie, but love this s***!

[RoboKlipsch]

 

Question: Would single "point" source surrounds and rear be best or would an array of say 4 full range speakers spanning 4-6 feet long be best for a more dispersed sound?

 

The choice is really between point sound localization (sound effects only) and "listener envelopment" (LEV) for surround sound like music and ambient sounds, as it turns out.  The following figure will give you some idea of the contribution to the surround sound effect vs. position of loudspeakers.  I think that you'll find that the loudspeakers located far behind the listeners aren't very effective, in fact, they detract from the listening experience:

 

 

So placing surrounds becomes a trade-off between sound localization and "immersion".  Since immersion is the dominant effect for movies (percentage of listener's time) I'd think about placing the surrounds for best envelopment and for "timbre matching", which is a function of the coverage angles of the full-range channels and their frequency response relative to each other.  So if you use a loudspeaker surround type that is much wider than the fronts, you'll never get the timbres to match.  That's saying that point source and matching the coverage angles of the front three loudspeakers is actually important.

 

However, there is another group of people that believe that just being able to splash around sound in the room from the back surrounds is good enough. 

 

Since I listen to music recordings that localize music to each surround channel, I try to match timbres.

 

Chris

 

This chart should be put in a sticky thread for basic speaker setup.  It's the most clear and concise summary of speaker placement and results.  Chris A - you're the man on this stuff!

[Zen Traveler]

I also listen mostly to multichannel music and for both it and movies use the Dolby PLIIz (heights as well) feature which matrixes the side surrounds with the rears and there is a more enveloping sound with some 5.1 music seemingly having a discrete rear channel

The figure provided above was from a paper where the researchers were using 24 surround loudspeakers in a ITU "standard room", then using combinations of surrounds shown in the individual columns. The listeners were not told which loudspeakers were on and which ones weren't.

What the data says from that experiment is that you don't need 24 loudspeakers to approximate the sound experience. In fact 5 surround channels do very well, indeed. Perhaps the acoustics of your room differs from the ITU "standard room". I've found that having a room that's about 40' deep is much better in terms of listener envelopment than having rear surrounds...so I don't use them, and I put the surrounds at about 80 degrees from the front centerline of loudspeakers so that the chairs we sit in don't interfere with the direct sound arrival. That has worked best for my listening room--by far. The plot above also bears that out.

Chris

First let me say that Chris' post above this that shows the study of speaker positions....that's the s***! Few that I've seen have a definitive grasp of what works, how well, and what you lose if you do something different. That chart says just about everything about basic placement.

If you read closely to what he wrote above...he is saying that his surrounds are NOT at 90 degrees or more...meaning they are not behind the seating position or even with it. They are slightly in front. And the study he posted shows that from maybe 60 degrees up until 120 degrees you get a great room response.

So there is your answer....you can put the surrounds in a 5.1 setup IN FRONT of the seating position, and still achieve great surround, perhaps ideal. The question you should pose to Chris and the others then is what speakers will do best in THAT situation...where the sidewalls and backs are at the seating position. Bookshelves? I'm guessing an RS or RP surround would be incredible. I'm a newbie, but love this s***!

I agree that Chris knows his stuff, but he and I were discussing different approaches and my comment dealt with rear speakers in conjunction to using surrounds and the processing done in the preamp.

[twk123]

I have wondered about this as well. For movies I have always wanted to try bouncing my surrounds off a 3d quadratic diffuser to hide the point source. For me, 'localization' means, "Cool, I can hear my left/rear surround channel now." But for 5 channel music its a totally different story, especially if its just you in the sweet spot. 

[RoboKlipsch]

 

 

 

I also listen mostly to multichannel music and for both it and movies use the Dolby PLIIz (heights as well) feature which matrixes the side surrounds with the rears and there is a more enveloping sound with some 5.1 music seemingly having a discrete rear channel

The figure provided above was from a paper where the researchers were using 24 surround loudspeakers in a ITU "standard room", then using combinations of surrounds shown in the individual columns. The listeners were not told which loudspeakers were on and which ones weren't.

What the data says from that experiment is that you don't need 24 loudspeakers to approximate the sound experience. In fact 5 surround channels do very well, indeed. Perhaps the acoustics of your room differs from the ITU "standard room". I've found that having a room that's about 40' deep is much better in terms of listener envelopment than having rear surrounds...so I don't use them, and I put the surrounds at about 80 degrees from the front centerline of loudspeakers so that the chairs we sit in don't interfere with the direct sound arrival. That has worked best for my listening room--by far. The plot above also bears that out.

Chris

First let me say that Chris' post above this that shows the study of speaker positions....that's the s***! Few that I've seen have a definitive grasp of what works, how well, and what you lose if you do something different. That chart says just about everything about basic placement.

If you read closely to what he wrote above...he is saying that his surrounds are NOT at 90 degrees or more...meaning they are not behind the seating position or even with it. They are slightly in front. And the study he posted shows that from maybe 60 degrees up until 120 degrees you get a great room response.

So there is your answer....you can put the surrounds in a 5.1 setup IN FRONT of the seating position, and still achieve great surround, perhaps ideal. The question you should pose to Chris and the others then is what speakers will do best in THAT situation...where the sidewalls and backs are at the seating position. Bookshelves? I'm guessing an RS or RP surround would be incredible. I'm a newbie, but love this s***!

I agree that Chris knows his stuff, but he and I were discussing different approaches and my comment dealt with rear speakers in conjunction to using surrounds and the processing done in the preamp.

 

ZT -- I apologize.  As I quickly wanted to quote Chris, I did so and didn't realize I brought your quote in also.  I intended to respond to the original poster and interpret the basics from Chris and simply say "Hey, the chart shows that in theory, putting the speakers in front of that big *** sectional sofa is not only OK but maybe ideal."  I did NOT intend to make it come across as it did, that I was replying to your post.  I'm too new to even pretend I can be sure enough to tell you what you should think.  I was honestly just excited to see someone use a study to show speaker positions and what the subjective response was.  There's no doubt it's only the beginning and the other factors not only influence but can completely change what should be chosen.  

 

I'm incredibly impressed with the newer Dolby IIx (haven't heard z).  It's not like the old days when Dolby was "eh".  They really process the sound well and I don't even think a 7.1 recording is all that important.  The Dolby processing does such a good job converting 5.1 that I'm not sure I could tell the difference short of a Gravity-like movie using poinpoint sound.  

 

Again sorry ZT I didn't want that to be our first interaction!

 

RK

[efzauner]

My feeble attempt at excel drawing! But you get the idea.

[Chris A]

If it were me, I'd move the couch forward at least 2 feet to get away from the back wall, and forget about any back surrounds, based on your drawing.  Then I'd find a way to mount the remaining two surrounds at or just above ear height while seated, and move the surround on the hall side to the wall, then correct the distance using an AVP or AVR.

 

Chris