Bottlehead Forum
General Category => General Discussion => Topic started by: ssssly on March 28, 2013, 01:06:37 AM
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Anybody have any cool tricks for opening up the image on one side of the sound stage?
Left hand side images properly.
Right hand side is stuck right on the speaker.
Have tried various speaker positions. Changes things about the overall image but not the fact that it stops at the right hand speaker.
The left hand side of the room is a a couple feet longer.
Is a half wall that goes into the kitchen on the right.
A couch and CD racks on the left.
Gonna try breaking up the kitchen half wall and see how that does.
Any other voodoo or suggestions?
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I would try some less conventional positions like moving the right speaker closer to the listening position than the left or visa versa. Also, if the speaker is too close or too far from a wall that can lead to that kind of problem. Try moving it very close to the wall, just toed in to the listening spot. I have bipolars so my reflections are different than cabinets.
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Man, I got the same situation in my room. Sometimes, it helps to treat the offending side of that room with acoustic panels or something. I toe in the LEFT speaker a little more than the right one(the one with less 'stage'). It is a kind of whatever works is legal sort of thing. Keep us posted, 'cuz there is an answer for this I'm sure.
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Hi there,
Audio Physic has a useful guide: http://www.audiophysic.de/aufstellung/index_e.html
Best
Michael
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Yeah, that's pretty good advice though I think they overplay the notion that curtains are bad. Most rooms are too live through the midband and if curtains help I'm all for it. The trick is getting some sort of treatment that diffuses sound in the very high frequencies and damps the sound in the lower treble through bass region. IME that diffusion is best served up at the back of the room. So curtains on the front wall or a side wall aren't necessarily bad, and certainly better than a glass window.
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Be sure that the phase of your speakers is correct. Getting a decent test disk/file is the only way to go for checking this IMHO.
One thing that I've found that can be helpful to tweak imaging is, after getting the best you can with placement/toe in etc, try adjusting the tilt and maybe height (unless your speakers are big floor mounted).
I used some wooden shims to tilt one of my Magnepans forward a bit and it really helped focus the images.
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1. ATS acoustic panels at the first reflection points. (or whatever brand suits your fancy)
2. Making sure both channels are actually balanced with an spl meter.
3. Experimenting with speaker positions. I tried one that worked well: Measure the distance between one speaker and your primary listening position. Make the distance between the speakers 80% of that first number. Make sure the other speaker is also the same distance to listening position. If it's still not great try spreading the speakers apart in 1 inch increments. They may need some more space from the back walls too.
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Hi there,
Audio Physic has a useful guide: http://www.audiophysic.de/aufstellung/index_e.html
Best
Michael
Great article, thanks Michael. I just got my phasing right so both speakers sound about the same volume. Now with the help of this article I can improve my soundstage.
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I get the speakers a foot or two away from the side walls. I have Michael Green sound panels at the first reflection. Use a mirror to determine the first reflection. You sit in the listening position and have someone move a flat mirror along the wall. When you see the speaker in the mirror you have found the first reflection.
I have a quilt mounted on the wall behind me, the wall behind the speakers is pretty live. But the speakers are 8 feet into the room.
I have had some odd images on the right that I found were caused by a cabinet against the wall. The sound from the right speaker was bouncing back and giving me a really odd placement. I have move the cabinet 4' further from the speakers. It helps.
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I have been strugglling with the same issue - one side the speaker is closer too the wall and on the other, there is a doorway and window. hence, each side has totally different reflections. Unfortunately there is no other way to arrange things in this small room.
For me it is more of a balance issue. I move the offending speaker 1/2 closer to my sitting position and that tends to be enough to balance things out.
drew.
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Drew, I know that this is not the perfect answer, but I too, have a room with the same associated problems as yours. For me, after doing all that I can with positioning, etc. the coarse/fine volume control helps somewhat. I guess it's not much different than a balance control, and I know that this is not a balance/volume issue, but it helps non the less. I agree with Graingers idea of using a mirror to locate those reflections most troublesome. There may be a point of diminishing returns given the conditions in the first place, but it's all we can do.
One last thing, I did experiment with sticking my entire system in the corner, giving all new directions for the reflections. Results were mixed but not unpleasant. My wife thought otherwise.
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Roy at Green Mountain audio raves about corner placements - you really do need the right room for that though - it's always something that keeps us just out of reach of audio perfection! I'm still thinking of building that diffuser for my room . . .
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After another night of tweaking it is getting a little better.
First, the speakers are frugal horns. So I am pretty much stuck with them up against the back wall. Unless I go with a dedicated woofer from about 100hz down. Which kind of defeats the purpose of the speaker.
After about 30 different speaker positions the right speaker is now 1.5" further right than equidistant from the center. And toed in 20 vs 16 degrees for the left speaker.
This was a serious move in the right direction but I think room treatments are definitely in order. I've got a nice Persian rug that is about the size of the half wall on the right. Gonna see where that gets me and I'll report back.
Oh and the speakers are in phase. After the first time I spent a week repositioning speakers because they didn't sound right just to figure out the were out of phase, is the first thing I check. Was certainly a self critiquing realization.
And that link if a great read.
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Room symmetry and symmetry of speaker placement are both very important to getting the best imaging. If the room isn't symmetrical, get the speaker as far away from the walls as possible. And one can try putting acoustically absorbent screens behind and beside the speakers to reduce the influence of the asymmetric walls. You can see what I'm talking about here:
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fwww.bottlehead.com%2FBH_08_3.jpg&hash=5d7a1e630321f2930d658edb31b35231586fd6ff)
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Looks like 10 amps per side! How does that work?
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It's only 9 per side - the 10th is the active crossover.
Four woofers, 1 amp each, all Paramounts.
Inefficient midrange with four amps in an unusual arrangement to combine their power, more Paramounts.
One tweeter amp - was originally an SR45, more recently ... another Paramount!
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This thread inspired me to try some experimentation. I have a 14x18 ft room with a fireplace in the middle of the speakers. the fireplace is not centered on the wall. The right speaker is 2 ft from the wall, the left speaker is 3 ft. The right wall is flat drywall, the left has a door and window. speakers are 32 " from the back wall. I also have my gear behind the right speaker on a rack, the only place I can currently fit it.
In this configuration, my soundstage is shifted to the right speaker. I have absorption panels on the front and back walls. I thought that the problem was the right speaker being closer to the wall. So I experimented putting some sound absorption there (in this case a very thick comforter, not sure what the technical specs are :)) This made the shift more apparent. So I tried the absorption on the left wall and voila, the soundstage opened up to the left in a not very subtle way. Quite surprising and a bit counterintuitive for me. What was a dead zone of sound is now filled with voices and instruments.
So it is definitely worth getting some serious room treatments in place and experimenting with placement. I am going to continue to experiment and try some assymetrical treatments as well. I did try moving speakers around and even centered them at one point without as much impact.
Anyway, I hope this gives you some ideas and good luck with it.
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Get into near field listening. Once you get closer to the speakers, the room reflections etc will take a back seat. Try it.
shreekant :)
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I'm only 10" from the speakers. So os fairly near field.
Pulling the speakers away from the wall eliminates all bass below 90hz. They are rear loaded horns and use the wall as part of the horn expansion. So pulling them away from the wall isn't really an option either.
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Guys,
I've had nothing but difficult, assymetrical rooms, and as Doc says, start with the front wall, and the first reflection points, but after that the thing I have found to work by far better than anything else is diffusion panels instead of absorption. And you can do an awful lot with just a few panels -- I've typically found them to be best behind or off to the side of the speakers, and one overhead on the ceiling.
The only other thing that worked, but I eventually abandoned as it was just cumbersome, was a diagonal room setup. But of course my rooms have all been fairly small, so I was pretty limited in how far out into the room I could pull the speakers.
Drew, I'd deefinitely go with that diffuser panel first -- it will also give you something to build ;-).
I think there was a post in the speakers section by another guy here who had a similar issue with his Lowther speakers and found a homemade diffuser panel to do the trick.
I'm starting out on my new room with the Michael Green RoomTune pack, but I will probably still need a diffuser or maybe two at some point. This room is asmall, so I'm pretty cautious about over damping the room with too many absorption panels. I'm certainly no expert in this, but I do have a good amount of experience playing around with small assymetrical rooms, and have been able to achieve some incredible listening spaces where the room walls virtually are not there and with amazing soundstagging... but it tookk a whole lot of time and experimentation and super critical speaker placement as well -- and the speakers were in a perfectly parallel stance when all was said and done.
-- Jim
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check out Jim Smith Get Better Sound. i bought the book a few years ago and think it is full of useful setup tips. this would not be a quick fix but might be worth it. i think by now he has several different books and even a setup DVD. good luck tweaking
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I'm only 10" from the speakers. So os fairly near field.
Pulling the speakers away from the wall eliminates all bass below 90hz. They are rear loaded horns and use the wall as part of the horn expansion. So pulling them away from the wall isn't really an option either.
I also use horns and have pulled the speakers 5 feet from the wall and used a sub. But, if I may give you a new direction..........are your cables broken in? You may laugh because you have put in a few hundred hours on them, but with single drivers, I have found that it does take a lot of breaking of all cables to get the sound stage right...... just my experience.
shreekant :)
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I think the following may apply to this topic of room treatment. It is as much a question as anything. I have been thinking about how different materials for absorption handle different frequencies, and I have wondered in cases where a room needs a lot of absorption on one side, whether or not 'memory foam' would be more useful than other materials. Your thoughts everybody.
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A standard sound-absorbent material has the optimum flow resistance - that is, it is harder than air and softer than wood. :^) You can blow through it with moderate effort, more like a pillow than a fiberfill comforter. It will absorb sound pretty well when the material is more than a quarter-wave thick. A wavelength at 1kHz is about a foot (34cm actually) so a 3" pad is good down to 1kHz. The memory foam I've seen is very hard or impossible to blow air through, so it would not be a good absorber.
That's from the simplest theory. Clever material designers can push this lower, maybe as much as an octave, by exploiting more subtle material parameters and/or non-uniform materials. And a thinner pad of higher resistance will absorb less energy but do it down to a lower frequency.
I have left out bass traps which get to much lower frequencies but only in a more narrow frequency range, by exploiting resonances.
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Thank you Paul, Everything has a song when it comes to resonance. I have long been interested in acoustics, as things are not as you might expect. This leads me to constant curiosity.