Bad position of speakers for stereo: ideas for improvement

mfur

Standard Member
Hello,

recently I built my first in-room sound system (outside super-budget setups), primarily designed for home cinema. System is in living room that is still being finalized.

Room is 3.6x9.2x2.4m and extends to the kitchen. Attached picture taken from listening position, ~3.4m from speakers.
As you can see front stereo pair is in bad position: mounted high walls too close to them. Left speaker has wall on one side and right speaker is in corner created by chimney - walls on both sides. I imagined that this will be suboptimal but couldn't come up with any better mounting idea that wouldn't interfere with the room practical requirements. I imagined it will be suboptimal - but not as bad at is turned out.

I am satisfied with the setup when used in 5.1 mode for movie watching, 5.1 music or electronic music in stereo where imaging is not important. Height of the speakers seem not to be problematic. Speakers are turned with tweeters down. High position was selected so they are more in line with center speakers and for functional reasons.

As for stereo - it is disaster. Imaging is tragic. Vocals seem to come either entirely from left speaker or from each speaker separately. Best case vocals are centered for specific pitches in certain calibrations (mainly with specific phase delays - speaker distance configurations).

Today I took multiple measurements of various speakers to get insight on what is going on. I was shocked when I saw FR comparison of left and right speakers. There are multiple areas that jump out. ~170-200Hz and ~280-320Hz ranges are ~10dB lower on right speaker than on left.
That corner where right speaker is located seems to introduce all kinds of issues (room modes?). I also wanted to put subwoofer there but it has the same issues as front right, it's response is not linear at all. Blue line 20-100Hz chart shows FR of subwoofer when placed in that corner below right speaker. Red line is from position in room corner by the couch.

Can you help me with what options I have in this situation? With current mounts I can't move speakers more than a few centimeters. I did play with turning them right/left, directly towards listener vs a bit apart and using different angles without much improvement. Even if I could move mounts I wouldn't know where to put them. I can't somehow move right speaker to the left so it wouldn't have wall behind it - it would at least interfere with walking in and out of the room when projector screen is in use if I managed to find appropriate mount. I could potentially move speaker a bit bit further from the wall with modifications to the mount, but not sure if that would do any good.
What are reason for frequency responses I get for the right speaker if I am not looking into them too much? Seem very bad. Could I do anything with room treatment in the offending corner - diffusers, absorbers? Perhaps with software?

Listening to stereo in current state is driving me crazy. I apologize if I posted this in wrong forum section - it is not strictly HiFi, but I am specifically troubled by stereo reproduction / imaging. Any suggestions will be appreciated.

Components:
  • Sony STR-DN1050
  • B&W DM602 S2

I heard those speakers in different room (albeit with different Marantz stereo receiver) so I know that they are capable of excellent stereo reproduction (for my ears).

room.jpg
FR_front_leftBlue_rightRed.jpg
FR_subwoofer_blue.jpg
 

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Paul7777x

Distinguished Member
I can see what you mean. That graph is awful! I feel your pain sir.

The positioning is dire and the Sony is not helping.

The only possible solution here is some DSP room correction.

I’d suggest you sell the Sony and find yourself an older Anthem MRX.

The ARC software will help enormously in your room.

And they are top class as stereo amps as well.


And, if you can’t lower the speakers, but you should,
I’d suggest turning them down at least a few degrees to get the tweeter beaming closer to ear height.
 
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Paul7777x

Distinguished Member
This would be a better bet than the Sony.


but also keep your eyes open, if you’re interested, for the MRX 500 or 700, and if you’re lucky, then the 310, 510, or 710 might be possible and not too much more expensively.
 
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mfur

Standard Member
I can see what you mean. That graph is awful! I feel your pain sir.

The positioning is dire and the Sony is not helping.

The only possible solution here is some DSP room correction.

I’d suggest you sell the Sony and find yourself an older Anthem MRX.

The ARC software will help enormously in your room.

And they are top class as stereo amps as well.


And, if you can’t lower the speakers, but you should,
I’d suggest turning them down at least a few degrees to get the tweeter beaming closer to ear height.
Thanks for suggestion.
Speakers are already turned with the tweeters down.
Didn't know that Sony was bad with DSP. Unfortunately no Anthems are currently available locally. I'll look into them and DSP in receivers in general.
What are the chances that such situation can be resolved by DSP? I'm new in hifi world, but I read about how fighting room modes/nulls (if this is the case here - I do not know) is not a good idea.
 

Paul7777x

Distinguished Member
I can’t see any other way to improve your stereo set up.

In a sense it is not wise to attempt to completely fill nulls, especially in bass frequencies.

But it is not at all difficult for modern DSP to limit them and to make the v shape more narrow and therefore less obvious to the ears.

Modes are child’s play. Simple. So the combination of getting rid of the peaks and limiting the nulls is very useful indeed. Making the difference as small as possible is the the only way to proceed.

There are frequently MRXs on eBay. The reason I mention Anthems in particular is because ARC really is impressive. Even the first version.

Audyssey is noticeably less so, and I never got on with it. DIRAC is also excellent but a stand alone unit to fix the stereo is around £450 new. And very rare second hand.

But, short of a new room with plenty of space to situate the speakers, good quality DSP is your only chance I’d say. And ARC is the cheapest very good one.
 

Paul7777x

Distinguished Member
Ps, for stereo especially, it’s also very important to get the speaker levels as close as possible to the same volume from the listening position.

That’s is, any discrepancy between any part of the frequency range in absolute volume between left and right ruins a stereo set up for music.

For instance in your graph there is at least a ten DB difference between speakers at 80Hz, 200hz and 300hz. That’s a huge gap.
 

gava

Well-known Member
Do you have a budget to fix this?

For that kind of mounting position you would ideally have a CBT style array, and a (sub)woofer on the floor, need a decently powerful amp to drive and preferably a DSP system if you can.

Doesn't need to be crazy expensive, could manage for perhaps £1,500.

Otherwise forget stereo and just add extra speakers to get better coverage in the listening position and flatten out the curve a bit.

What speakers are you using on the walls?
 

mfur

Standard Member
I don't have any hard budget defined but I do strive for good price/performance point. 1500€ sounds completely reasonable if that would provide we me long-term satisfaction. I prefer to buy second-hand as that gets me much higher grade components in most cases.

My bar is not set all that high I think. Coming from car audio background I can say that my DEH-80PRS with 200€/pair Hertz fronts, 250€ Crunch amplifier and 350€ DLS sub is keeping me very happy for at least 5 years and I don't see I will ever need more than that. Stereo image is perfect, I can hear vocals fixed right in front on me over the steering wheel, practically outside of the car.
I kind of expected that DSP in Sony will be able to provide something similar in home, but it does not even compare.

Front wall-mounted speakers are B&W DM602 S2.
Center is B&W LCR60. Back speakers are Infinity HCS and so is sub - temporary ones so I can listen to something while doing research. Center was also Infinity HCS but it was bothering me so much that I replaced it very soon. Now I have Monolith THX 10 on the way as sub replacement (with leaving option open to add another one in future). Surrounds will probably be used B&W speakers to match tweeters on the front row.

Never heard of CBT arrays, will take a look. Looks strange and exotic on first sight :).

As audio/video source I am using almost exclusively PC. I'm planning to experiment with various software solutions like Dirac Live to at least get a feeling what DSP can do as Paul7777x suggested. I'd love to test Anthems, but they are not available here in Slovenia and I'd like to avoid costly shipping of delicate receivers if possible.
 

gava

Well-known Member
This sort of thing should give much better directionality (80Hz upwards) mounted in that position. You can then add a subwoofer(s) on the floor.

 

lindsayt

Active Member
Room is 3.6x9.2x2.4m and extends to the kitchen.


View attachment 1609525

That's the first time that I've seen a screen hanging in a room with a large space behind it, instead of against a wall.

It looks like a domestic nightmare. As well as being acoustically odd with the centre speaker hanging from the ceiling and blocking a large part of the screen along with the mains stuck up on the wall.

I'd be looking to rotate the whole room layout by 180 or 90 degrees.

What does the room look like from the kitchen?

I'd rather have the screen in front of a window than in the middle of the room like that. Just make it a motorised or easily retractable screen. With the centre speaker below the screen and the mains with the tweeters at ear level.

Or have the screen facing across the 3.6 metre width of the room. And maybe go for dual concentric mains for the somewhat nearfield listening distance with that solution?
 

mfur

Standard Member
That's the first time that I've seen a screen hanging in a room with a large space behind it, instead of against a wall.

It looks like a domestic nightmare. As well as being acoustically odd with the centre speaker hanging from the ceiling and blocking a large part of the screen along with the mains stuck up on the wall.

I'd be looking to rotate the whole room layout by 180 or 90 degrees.

What does the room look like from the kitchen?

I'd rather have the screen in front of a window than in the middle of the room like that. Just make it a motorised or easily retractable screen. With the centre speaker below the screen and the mains with the tweeters at ear level.

Or have the screen facing across the 3.6 metre width of the room. And maybe go for dual concentric mains for the somewhat nearfield listening distance with that solution?
Hi, thanks for response. Screen is motorized and not visible most of the time. Indeed it would be very odd if it would be down all the time.

Living room part of the place has slanted wall on one side, exit to balcony on the other, open to kitchen on third and plain wall on the last one. Makes positioning difficult.
Only potential orientation that would make any sense in my view is the one with couch by plain wall looking towards balcony exit. That would block the exit/window and still be asymmetric: slanted wall on one side and open on the other. No placement for center speaker in this position - it would be right at balcony exit.

I really like the current orientation because in usual mode with screen up is very open.

Never mind the funny center speaker mounting: It is temporary. It will be above projected image. I just replaced the center speaker - I drilled previous one and mounted it directly without any silly strings. However I don't want to drill new one until just yet. Will come up with nicer mounting though. Lots of things in room are currently temporary - still setting it up.
 

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lindsayt

Active Member
I would turn the room by 180 degrees.

Have the screen part way down the sloping part of the end wall. As far down as it will go whilst giving a comfortable viewing experience from the sofa.
Bring the sofa out and place it near where the main right speaker is now.
Centre and main speakers placed along the vertical bit of the end wall.
Possibly a change of main speakers to ones that will be happy placed right in the corners - depending how you get on with your existing speakers in that location.

The benefits would be that it would be much better for listening to music and watching TV whilst cooking. And it keeps your whole room more open plan when the projector is in use.

And it looks like you could house a bigger screen with my suggested layout...
 
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mfur

Standard Member
It's an interesting idea.
Main problem I see with it is that sofa would stick out in the middle of the room to allow (approximately) centered view of the screen and centered position between speakers. Alternately if put in the corner so it wouldn't stick out too much the viewing angle wouldn't be optimal, same for distance to speakers. Also projector and right surround speaker would still have to be mounted in odd way, so no esthetic improvement there. View from couch would be worse (less distance to wall, no view of kitchen when screen is up).
Kitchen has separate speakers in slanted part so this is covered.

This would also require disassembly of absolutely all mounts (screen, projector, speakers) and in-wall cabling which I'm not willing to do right now after setting them. But it is an option in the future when I get upgrade itch about bigger screen (90" now), projector dies or something like that.
 

lindsayt

Active Member
For the sofa, the main listening / watching position would be with your ears at the end of it, where it's sticking out most into the room. There's no good reason at all for the sofa to be symetrically placed in the room. I do almost all of my TV watching lying down on my sofa.

It's common for projectors to be ceiling mounted. Visually it would be vaguely the equivalent of an old fashioned light and shade in the middle of your open plan room.

There would be about 0.5 to 1 metre less distance between yourself and the screen? Is that a huge deal?

Your main speakers would have symetrical acoustic positioning. Which they have no chance of having with the current layout.

The kitchen speakers could be removed. And the rear surrounds could be mounted either where the mains are now, or in the kitchen wherever is most convenient. The location of the rear speakers is less critical than the mains. They only provide infill for gimmicky movie surround sound effects.

The plant pots or some low bookshelf type storage could be put against the vertical part of the wall behind the projector screen.

It is of course entirely up to you what you do with your home. I'm just giving you the best advice I can, given my experience of having a vaguely similar open plan kitchen and living room 2 houses ago. I used to really enjoy cooking whilst listening to music on a decent stereo system firing down the living area.
If a jobs worth doing, it's worth doing well.
 

mfur

Standard Member
Well, I'm certainly warming up to an idea. Love the sound symmetry that such layout would provide.

I even moved the couch yesterday for quick evaluation. For me it might work as sound has high priority, however my better half was not impressed at all. Got a straight veto. Might need some time 😀.

Such position do look symmetrical, however there is still large empty space behind listening position on one side and chimney corner on the other. Stereo speaker positioning methods usually specify that you should start at 1/5 - 1/3 room distance from the wall (or some similar rule with relatively long distances), but this wouldn't be possible to satisfy in any case in this room. I guess I will have to experiment and see if results are incomparably better than current position.

Surrounds would be in worse position that they are now, but they are indeed less important than fronts. Another practical issue is how to get HDMI cable from projector all the way to the receiver. This was done for current position when drywall was being placed, now it is much more difficult. I do have thin (~11mm) tunnel that could be used, but HDMI with connectors wouldn't fit in.

So my plan of action is to first try what I can do with room correction. Perhaps I get my hands on hardware such as Anthem with ARC or similar. While waiting for such opportunity, I will play around with on PC with REW / EqualizerAPO / Dirac Live trial.

I will also play with front speaker positioning under slanted wall symmetric position to see if I can get epic results that might convince my girlfriend 🙂.
 

eastsoutheast

Well-known Member
I would be looking at a pair of floorstanders which would work much better and place the tweeters at the correct height. The sub could move to the wall opposite the large blind next to the chair. There is not much you can do with the center but the above should offer a decent improvement all around.
 

mfur

Standard Member
I would be looking at a pair of floorstanders which would work much better and place the tweeters at the correct height. The sub could move to the wall opposite the large blind next to the chair. There is not much you can do with the center but the above should offer a decent improvement all around.
I have all the wiring ready for floorstanders, but center would be in entirely different height than L/R in this case. This is the main reason mains are mounted high so panning across speakers is more seamless. For movies it works great.

Also low mouting wouldn't solve the issue of asymmetric front placement (left near one wall, right near two walls) that I suspect is big contributor to bad stereo and is visible in big difference in FR between R/L.

First sub is on the way and I plan to find the best location for it. Currently the location with most linear response seems somewhere below front left. Below front right in corner is the worst one so far. Didn't measure your proposed position yet as it is unconvenient one, but I plan to.
 

ryart

Active Member
“As for stereo - it is disaster. Imaging is tragic. Vocals seem to come either entirely from left speaker or from each speaker separately. Best case vocals are centered for specific pitches in certain calibrations (mainly with specific phase delays - speaker distance configurations).”

Just a thought, have you checked that your speakers are wired in phase? That is, positive on the speakers to positive on the amp on both speakers. If the wiring is reversed on one speaker you could get the effect you are describing. Whilst your setup is, as you say, far from ideal, you should still get reasonable stereo imagery.

Don’t worry too much about the narrow nulls in your graphs, that is normal when looking at frequency response with smoothing at 1/24 octave. You will get a better impression of what you hear using smoothing at 1/3 octave. In any case there is little you can do about nulls, even with dsp, other than moving your speakers to a position with better compromises. Fortunately, the ear doesn’t tend to notice nulls as much as peaks, which happily can be reduced without too much damage.
 

ashenfie

Well-known Member
Killing two birds with one stone. First having a speaker hanging from the ceiling in front of the screen is never going to work consistantly . The window needs a blind when using the projector. What I did previously was have a project screen over the window. I had a 100% blackout blind (no light around the edges) and the the screen came down over the window area. So move the project and screen around to you project to the window.

Then maybe smaller speakers wall mounted. The centre could be roof mounted pointing down or better stand mounted behind the screen.

That means it would be open to the kitchen to the right. A movable partition of some type would be good to the right.
 

mfur

Standard Member
I can confirm that speakers are in phase. It is not quite that bad fortunately :). It is mostly that vocals mainly seem to come from left speaker or "center" seems to jump from center to the left. Some songs are quite nice - I guess that this might be because the vocals are just the right pitch that is reproduced similarly on both L and R..

Thanks for the hint about smoothing. Indeed it looks more normal with 1/3 or 1/6 smoothing applied. I am now looking into MMM (moving microphone method) of measurement so I can make more consistent measurements. Then I will apply smoothing and play with amplitude and (later) phase adjustments. Still new to this - looking into REW, Equaliser APO and rePhase.

@ashenfie screen over the window (exit to the balcony) is very problematic position. It is still very asymmetric for speakers and there are no placement for center (right at the balcony door). If I would be turning everything around, I'd probably pick symmetric orientation suggested by @lindsayt, although this one also has it's problems.
 

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