Years ago I bought a satellite/subwoofer speaker system (with passive crossover) the sound of which was never completely satisfying. It had good low bass, upper midrange, and treble, but the upper bass and low midrange was never quite sufficient. It had a "cold" sound instead of the warm clarity that I prefer. I obtained other speakers and relegated the sat/sub system to storage, eventually changing the crossover and getting closer to the sound I wanted but not putting it into regular usage.
I am in the process of converting a small barn loft into a combination workshop and sound production studio, and part of this process is installing a couple of speaker systems, one of which is the sat/sub. The loft is finished in painted drywall and has hard reflecting and diffusing surfaces with a plywood floor painted with oil-based floor enamel. Due to space considerations I placed the sat/sub against the short wall of the rectangular room in between some other items which made a sort of niche for the system. I hooked up a receiver and a CD player to run some listening tests and on all the music I played the system had an unpleasant hard sound, almost hornlike in its projection of midrange frequencies and dull sounding without treble clarity. Some instruments on familiar recordings were barely audible and there seemed to be almost no stereo separation, no spaciousness to the sound. The bass sounded all right, but the other effects made the speakers nearly unlistenable.
These effects were noticed at a listening distance of about two meters on axis. When I moved closer to the speakers (inside one meter) the sound improved considerably and had the clarity and pleasant tonal balance I remembered and preferred. "Aha!" thought I, "The room is at fault!"
I looked online at room treatment products available from various sources, and my impression was that they were quite expensive for what was supplied. I considered other materials for room treatment that were not specifically made for that purpose and settled upon memory foam. In my area (central United States) some of the big box stores sell what are known as mattress toppers, made from memory foam. The toppers are simply mattress-sized pads that are placed on top to provide more cushioning and comfort for the sleeper. The stores I shopped carried toppers in both 1.5 inch and 3 inch thicknesses. I bought the 1.5 inch topper which was manufactured with geometric patterns embossed into the memory foam, somewhat similar to acoustic treatment products. The topper manufacturer calls these patterns "Comfort Zones", and I thought that combined with the memory foam construction I might get a useful bit of both absorption and diffusion.
I trimmed the toppers to the dimensions needed and set to work. My setup involves the satellites resting on top of the subwoofer boxes which are hard against the front wall and have sharp-cornered structures on either side. I believe the satellites, which have small baffles of about 10 inches by 7 inches, were interacting with all of the near hard surfaces and refracting off all the corners to give an unpleasant quality of midrange hash to the sound. Basically I used one thickness of the topper material (pattern side out) to line all the reflecting and refracting surfaces in proximity to the speakers and added an extra thickness to the flat surfaces immediately to the outer sides of the baffles. I also rolled up some of the material and placed the roll lengthwise between the satellites (about one meter apart).
This treatment made a very noticeable improvement to the sound. The midrange hash is gone at the listening distance of two meters. The treble has a clarity from being in proper proportion to the midrange. Reverb tails are more audible. The improvement that leaped out at me, however, is the stereo separation. The instruments are now clearly discernible in the mix and their left/right positions are easy to identify. Now, the only question is: Do I want to treat the whole room with this stuff?
This is the first time I have applied sound treatment to a room (and the first time I believe it was needed). I have read many references to the effects the room has upon the sound of speakers, but since I normally listen at close range I had never before heard the room influence demonstrated so clearly. I am a convert!
I would be interested to hear from other members to know if anyone else has used memory foam material as room treatment. If anyone is interested in trying it, the mattress toppers I have seen are available in twin, full, and queen sizes, and I would not be surprised to know that king-sized toppers exist. The larger sizes are more economical as they provide more material for not proportionally more money. The price I paid was under $20.00 USD for a queen size topper.
It worked for me; maybe it will work for you.
I am in the process of converting a small barn loft into a combination workshop and sound production studio, and part of this process is installing a couple of speaker systems, one of which is the sat/sub. The loft is finished in painted drywall and has hard reflecting and diffusing surfaces with a plywood floor painted with oil-based floor enamel. Due to space considerations I placed the sat/sub against the short wall of the rectangular room in between some other items which made a sort of niche for the system. I hooked up a receiver and a CD player to run some listening tests and on all the music I played the system had an unpleasant hard sound, almost hornlike in its projection of midrange frequencies and dull sounding without treble clarity. Some instruments on familiar recordings were barely audible and there seemed to be almost no stereo separation, no spaciousness to the sound. The bass sounded all right, but the other effects made the speakers nearly unlistenable.
These effects were noticed at a listening distance of about two meters on axis. When I moved closer to the speakers (inside one meter) the sound improved considerably and had the clarity and pleasant tonal balance I remembered and preferred. "Aha!" thought I, "The room is at fault!"
I looked online at room treatment products available from various sources, and my impression was that they were quite expensive for what was supplied. I considered other materials for room treatment that were not specifically made for that purpose and settled upon memory foam. In my area (central United States) some of the big box stores sell what are known as mattress toppers, made from memory foam. The toppers are simply mattress-sized pads that are placed on top to provide more cushioning and comfort for the sleeper. The stores I shopped carried toppers in both 1.5 inch and 3 inch thicknesses. I bought the 1.5 inch topper which was manufactured with geometric patterns embossed into the memory foam, somewhat similar to acoustic treatment products. The topper manufacturer calls these patterns "Comfort Zones", and I thought that combined with the memory foam construction I might get a useful bit of both absorption and diffusion.
I trimmed the toppers to the dimensions needed and set to work. My setup involves the satellites resting on top of the subwoofer boxes which are hard against the front wall and have sharp-cornered structures on either side. I believe the satellites, which have small baffles of about 10 inches by 7 inches, were interacting with all of the near hard surfaces and refracting off all the corners to give an unpleasant quality of midrange hash to the sound. Basically I used one thickness of the topper material (pattern side out) to line all the reflecting and refracting surfaces in proximity to the speakers and added an extra thickness to the flat surfaces immediately to the outer sides of the baffles. I also rolled up some of the material and placed the roll lengthwise between the satellites (about one meter apart).
This treatment made a very noticeable improvement to the sound. The midrange hash is gone at the listening distance of two meters. The treble has a clarity from being in proper proportion to the midrange. Reverb tails are more audible. The improvement that leaped out at me, however, is the stereo separation. The instruments are now clearly discernible in the mix and their left/right positions are easy to identify. Now, the only question is: Do I want to treat the whole room with this stuff?
This is the first time I have applied sound treatment to a room (and the first time I believe it was needed). I have read many references to the effects the room has upon the sound of speakers, but since I normally listen at close range I had never before heard the room influence demonstrated so clearly. I am a convert!
I would be interested to hear from other members to know if anyone else has used memory foam material as room treatment. If anyone is interested in trying it, the mattress toppers I have seen are available in twin, full, and queen sizes, and I would not be surprised to know that king-sized toppers exist. The larger sizes are more economical as they provide more material for not proportionally more money. The price I paid was under $20.00 USD for a queen size topper.
It worked for me; maybe it will work for you.
"Basically I used one thickness of the topper material (pattern side out) to line all the reflecting and refracting surfaces in proximity to the speakers and added an extra thickness to the flat surfaces immediately to the outer sides of the baffles."
Any chance of a picture showing your remedy? Hard to imagine "all" the surfaces having been treated. Glad to read it worked!
Any chance of a picture showing your remedy? Hard to imagine "all" the surfaces having been treated. Glad to read it worked!
Sorry that I can not provide a picture; I don't own a digicam. When I say all the surfaces in proximity to the speakers, I mean the vertical surfaces to the sides of the satellites and the wall directly behind them as well as the horizontal surfaces of the subwoofer boxes upon which the satellites rest. I also treated the space between the satellites with the roll of memory foam that I mentioned in my first post. I did not treat the baffle surfaces of the subwoofers, nor did I treat the vertical surfaces beyond the "niche", but I now wonder whether I should consider doing so and perhaps extend the treatment to all the surfaces in the room that could accommodate it.
Sorry, no.
My intention with the first post was to alert any interested parties to a potentially useful and economical means of acoustic room treatment. The specifics of my particular situation do not seem to matter as much as the general concept, since the rooms and setups of everyone else will differ. If anyone else has already tried this material for this purpose I would be interested to hear about it, and if anyone else wants to try it I encourage you to do so. The more positive results that we can report would be more confirmation that it can work in a variety of situations and setups, and if it does not work for you I believe that would also be useful to know.
It seems to me that the main negative aspect of this method is that it does not look tidy. Add to that the probability that as it is made of polyurethane foam it will yellow with age and light exposure and the Significant Other Acceptance Factor will probably plummet to Zero, Nought, Nada. But, perhaps others can find ways of improving its appearance in a room, possibly covering it with an attractive acoustically transparent fabric such as grill cloth. Or, of course, if the S.O. becomes too vociferous in His/Her/Its objections, the dedicated DIYer could tell He/She/It to F.O.
My intention with the first post was to alert any interested parties to a potentially useful and economical means of acoustic room treatment. The specifics of my particular situation do not seem to matter as much as the general concept, since the rooms and setups of everyone else will differ. If anyone else has already tried this material for this purpose I would be interested to hear about it, and if anyone else wants to try it I encourage you to do so. The more positive results that we can report would be more confirmation that it can work in a variety of situations and setups, and if it does not work for you I believe that would also be useful to know.
It seems to me that the main negative aspect of this method is that it does not look tidy. Add to that the probability that as it is made of polyurethane foam it will yellow with age and light exposure and the Significant Other Acceptance Factor will probably plummet to Zero, Nought, Nada. But, perhaps others can find ways of improving its appearance in a room, possibly covering it with an attractive acoustically transparent fabric such as grill cloth. Or, of course, if the S.O. becomes too vociferous in His/Her/Its objections, the dedicated DIYer could tell He/She/It to F.O.
With respect the cheapest memory foam mattress I could find was £45 and you could buy two packs of rockwool for that amount. I'm glad you got a good result, tho.
I hope you guys are using fire rated foam, the dimpled stuff is incredibly flammable otherwise.
I assume memory foam is what is used in mattresses? Might want to check that too.
A lot of small studios and night clubs used the stuff here in MA/RI until a fire at a night club back in the 1990s killed several dozen people.
I assume memory foam is what is used in mattresses? Might want to check that too.
A lot of small studios and night clubs used the stuff here in MA/RI until a fire at a night club back in the 1990s killed several dozen people.
The Station nightclub fire - Wikipedia
One would hope that mattress foam is fire rated. But it pays to find out.
One would hope that mattress foam is fire rated. But it pays to find out.
After reading all the replies I did some more online research and consulted my own records and have discovered that I made an error in what I posted. Some time back, in an effort to improve my sleeping comfort, I had purchased a couple of different foam mattress toppers, one of which was memory foam, the other a standard polyurethane topper. The one I used for the sound treatment was actually the standard polyurethane one with the embossed geometric patterns. Until now I had no reason to bring it out of storage and somehow in my mind it had assumed a memory foam status. In my defense I can only plead my own advancing age and the fact that when compressed the topper does not immediately spring back to full dimensions, thus lending the impression of memory foam. Anyway, mea culpa, but the effect the foam had on the sound is still real and valid.
In regard to pricing, I checked on Amazon (U.S.) and found various actual memory foam mattress toppers in queen size (both plain and patterned/dimpled) for less than $50.00 USD, with smaller sizes costing less. The standard poly foam topper in queen size, purchased locally, was as quoted above, less than $20.00 USD. I don't know if the patterns/dimples in the foam make much difference in the effects on the sound, but I suspect that they don't have a negative influence. And once again, for clarity, I refer only to a mattress topper, not a mattress proper.
In respect to any fire hazard, I quote verbatim from the package of the standard urethane foam topper:
"This article meets the flammability requirements of California Bureau of Household Goods and Services Technical Bulletin 117-2013. Care should be exercised near open flame or with burning cigarettes. The materials in this product contain no added flame retardant chemicals. The state of California has determined that the fire safety requirements for this product can be met without adding flame retardant chemicals."
Also on the package is a large red box that says:
"WARNING
URETHANE FOAM IS FLAMMABLE"
Subsequent to this is a lengthy description of the hazards of burning urethane foam. It appears that once the stuff ignites it presents a serious danger.
I personally do not use and do not allow any open flames or burning tobacco products in my home and workshop, so I am not too concerned about any fire hazard, but it might be wise to limit the amount of foam one installs for this particular use. I will keep what I have installed but will probably not add any more as I am satisfied with the improvement I achieved. I suggest each person considering using it do your own research and decide whether the risk is significant enough in your own situation.
Again, my apologies for the confusion about the kind of foam I used. Memory foam or not, I believe it has utility for acoustic room treatment.
In regard to pricing, I checked on Amazon (U.S.) and found various actual memory foam mattress toppers in queen size (both plain and patterned/dimpled) for less than $50.00 USD, with smaller sizes costing less. The standard poly foam topper in queen size, purchased locally, was as quoted above, less than $20.00 USD. I don't know if the patterns/dimples in the foam make much difference in the effects on the sound, but I suspect that they don't have a negative influence. And once again, for clarity, I refer only to a mattress topper, not a mattress proper.
In respect to any fire hazard, I quote verbatim from the package of the standard urethane foam topper:
"This article meets the flammability requirements of California Bureau of Household Goods and Services Technical Bulletin 117-2013. Care should be exercised near open flame or with burning cigarettes. The materials in this product contain no added flame retardant chemicals. The state of California has determined that the fire safety requirements for this product can be met without adding flame retardant chemicals."
Also on the package is a large red box that says:
"WARNING
URETHANE FOAM IS FLAMMABLE"
Subsequent to this is a lengthy description of the hazards of burning urethane foam. It appears that once the stuff ignites it presents a serious danger.
I personally do not use and do not allow any open flames or burning tobacco products in my home and workshop, so I am not too concerned about any fire hazard, but it might be wise to limit the amount of foam one installs for this particular use. I will keep what I have installed but will probably not add any more as I am satisfied with the improvement I achieved. I suggest each person considering using it do your own research and decide whether the risk is significant enough in your own situation.
Again, my apologies for the confusion about the kind of foam I used. Memory foam or not, I believe it has utility for acoustic room treatment.
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I’ve used this before for something similar, is what you want when there’s a fire and you need to do some ‘splaining afterwards...
Armacell Product Selector - AP ArmaFlex, AP ArmaFlex FS - Duct Liner and Wrap Insulation
Seems to be effectively centered around 5K hz.
Armacell Product Selector - AP ArmaFlex, AP ArmaFlex FS - Duct Liner and Wrap Insulation
Seems to be effectively centered around 5K hz.