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Speaker Asylum General speaker questions for audio and home theater. |
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Speaker Asylum General speaker questions for audio and home theater. |
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In Reply to: Re: For Leftiself (and Susan) posted by Susan on January 5, 2002 at 14:53:37:
Susan,I've got no experience with rooms as tall as those you and Leftiself has. I've got 10' ceilings and that's it. I'm not certain what effects such a tall ceiling will have apart from (1) increasing the volume of the space loaded by the speaker which is likely to mean you need to set volume levels higher than you would with a normal ceiling and (2) probably ensuring that floor to ceiling nodes are likely to be significantly different than the nodes in the other 2 dimensions which should help smooth bass response a bit unless the ceiling height is a multiple of one of the other dimensions in which case nodes will be replicated and room response will get bumpy. It's possible that the floor to ceiling node will reinforce a port tuning frequency and you may get some boom that way. What's more likely is that the large space allows a lot of reverberation and that's what produces your "boominess" - the low frequencies just hang on for too long. Try clapping your hands and see how long the echo persists, then do it in a normal room and compare. Ideally it should cut off as quickly as in the normal room or perhaps even a little quicker.The only way to reduce the duration of the echo - the reverberation time - is by absorption, especially in the corners and also mid wall helps.
What all 3 of us have in common is a speaker "in a corner", even if it's a bit out in the open, and one that isn't in that sort of position because there's no wall within a long distance to the side. Effectively the first speaker gets a lot of assist from the corner, hence the fullness in sound of your right speaker, while the other gets a bit of support from the rear wall behind and nothing from the side.
What we would all love is symmetrical placement but there's no way of physically doing it by putting in a wall. The solution is to place absorption around the corner to reduce the reinforcement the speaker there receives, thereby balancing the sound. The bass trap in the corner and the absorbing panels should do that.
What you should end up with is a better balance between the sound of the two speakers but you may still have the boominess, hopefully reduced to some degree. If that's the case, then you could look at trying to put bass traps out in the corners of the adjacent areas if that's possible. I don't know how effective that will be because of the height of the ceiling but it might help a bit. I'd try one of the corners to start and then move on to others. You may not be able to fix it entirely but I think you can get somewhere with it.
Jon Risch has a "recipe" for quick and dirty bass traps which just involves sticking several roles of fibreglass insulation still wrapped in their plastic bags in each corner. You can wrap the bags with open-weave material to dress them up. I've got a fairly live room and didn't want the high frequency reflection that the plastic bag gives and I wasn't happy about fibreglass. What I did was buy some bags of wool/polyester blend insulation batts but straight polyester will do and wrap them with wire fencing mesh to compress them to a density of 2 lb/cu ft. I then wrapped the wire mesh in thin polyester batting from a craft shop and had a bag made from loose weave curtain material to cover them. Using one bag of batts per trap produced a bass trap a bit under 4 ft high, 21" wide and 18" deep. You can test how they will work pretty quickly by just tossing the bag of batts into the corner as it comes - compression in the bag is likely to be close to the right density - so that will give you a rough idea, though the plastic will be reflective of high frequencies. If you can persuade a hardware store to let you take some bags of batts with the option of returning them unopened if they don't work, you can get a very quick idea of whether this approach will help. A few minutes tossing bags of batts in corners and time to play the disc which gives you the most problems and you will have a pretty good idea of whether you want to go to the expense and effort of dressing up the traps and making some absorbent panels. You might want to stack 2 bass traps this size in some of the "taller" corners to get more effect, especially if you can't put them in every corner because of the way that space is currently being used.
I wouldn't worry about diffusion devices out in the adjacent area - if there's too much reverberation then diffusion won't help reduce it.
In a space like that you'd really want modern furniture, wouldn't you? I don't have that much space but I just spent a fair amount of time looking for a decent listening chair and ended up placing an order for the Le Corbusier chaise-longue that Mirage were showing in their ads in Stereophile some months ago. I think it would really look great in a space like that but it's likely to look cramped in my room, still I bought it for the physical comfort and I'll get that. I like fairly firm seating and all of the standard recliners were way to soft for me.
David Aiken
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- Re: For Leftiself (and Susan) - David Aiken 23:37:54 01/05/02 (0)
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