Hello,
I'm planning to make a room in the basement where there should be good acoustics. I was thinking of putting up some kind of absorbing mat or something similar on the walls.
But the problem is that as soon as you touch the subject of "acoustics," everything becomes really expensive!
What is most common is to put up mats or panels as in the attached picture. This costs around 700:-/m2, and I have around 45m2 to cover = unfortunately not feasible with my budget.
Is there a budget solution? This foam is used, among other things, as packaging material for electronics, for example.
Best regards,
Stefan
I'm planning to make a room in the basement where there should be good acoustics. I was thinking of putting up some kind of absorbing mat or something similar on the walls.
But the problem is that as soon as you touch the subject of "acoustics," everything becomes really expensive!
What is most common is to put up mats or panels as in the attached picture. This costs around 700:-/m2, and I have around 45m2 to cover = unfortunately not feasible with my budget.
Is there a budget solution? This foam is used, among other things, as packaging material for electronics, for example.
Best regards,
Stefan
The principle of damping is that heavy materials should be set into motion to dampen the energy. The best sound damping is achieved with steel studs + mineral wool + plastic sheeting that is airtight, heavy, and robust.
Isn't there a difference between absorbers and soundproofing though? Soundproofing ensures that sound doesn't come in/out, but it still echoes nicely in a large well-plastered room. Or am I thinking wrong?byggarätt said:
Maybe heavy drapes (like cinema curtains) could help?
Well, what do you actually mean by good acoustics then?stew said:
Choirs and soloists usually love the acoustics in large stone churches, and foam and mineral wool only ruin the acoustics.
Otherwise, you usually talk about both damping and diffusion. And the right thing in the right place and in the right amount.
So, what are you aiming for?
I'm aiming for a home theater room. The room doesn't need to be soundproofed, the only priority is that the sound from the home theater system should reflect well from the walls (and, in extension, the ceiling).Mikael_L said:
Regards,
Stefan
As mentioned above.
A frame of regular 45-rule. Insert insulation, preferably the heavier ground board. Staple tightly woven fabric on the front and back. Hang on walls (and screw up in the ceiling if you like). Neat, simple, cheap, and effective.
Thick curtains are another option, but they don't dampen frequencies as low.
A thick carpet covering the entire floor is also good, providing a large dampened area.
The above are absorbers.
Diffusers are also good, bookshelves filled with books (of different sizes) and films work well.
The next fun word is diffraction, but that feels a bit advanced for the home.
A frame of regular 45-rule. Insert insulation, preferably the heavier ground board. Staple tightly woven fabric on the front and back. Hang on walls (and screw up in the ceiling if you like). Neat, simple, cheap, and effective.
Thick curtains are another option, but they don't dampen frequencies as low.
A thick carpet covering the entire floor is also good, providing a large dampened area.
The above are absorbers.
Diffusers are also good, bookshelves filled with books (of different sizes) and films work well.
The next fun word is diffraction, but that feels a bit advanced for the home.
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Room acoustics is an almost endlessly vast subject. 
Furthermore, there are no absolute truths; if you ask three experts, you'll get three different opinions on how it should be.
Some people work a little "cautiously" with room acoustics, often pressured by either the budget or the room's design (and/or other usage). These rooms often end up being slightly better than completely "untreated" rooms, but far from what can be achieved if you go a bit more uncompromisingly. In this category, there’s often a dampening rug on the floor, attempts to hang suitable curtains in various spots, and finally, some bookshelf or similar in a good place.
Others work very hard with damping; I myself lean towards this category since hearing a stereo in a completely anechoic room, and I believe that in a typical living room, you can hardly dampen enough.
Others aim much more towards diffusion and want to set up irregular surfaces everywhere.
Yet another group primarily wants the reverberation times to be equal across all frequencies.
And so most people probably work with a partially combined approach of these strategies. Yes, even design often needs to be considered to some extent.
In my opinion, there are two major culprits, and one of them is often very difficult to deal with.
1. Early reflections, the first reflection against hard surfaces in the room.
2. Standing waves in the bass area, up to mid-bass depending on the room's size.
1. This is most easily addressed with damping in the right places. The right places are where you can see one of the speakers from one of the listening positions if you place a mirror against the surface. Put a thick woolly rug on the floor between the speakers and the listening area. Build frames out of 22x95mm timber, fill with mineral wool, and cover with a beautiful fabric, placing these absorbers on the walls in suitable places. Also, put one or several on the ceiling in the right place.
2. This is a tricky issue, some rooms have an enormous amount of problems with this and are difficult to resolve. One solution is Helmholz absorbers tuned to the correct frequencies (up to 3 different = the room's 3 different dimensions) placed in the corners of the room. There are also active solutions that capture sound with a microphone and play the sound back in anti-phase, thereby counteracting the standing waves. These work for all frequencies, so you don't need 3 of them.
But what you're really asking about relates to category 1. I personally am installing a Rockfon acoustic ceiling in the living room as we build; this dampens broadband down to almost 500Hz, frequencies below this I have to fix in other ways. You can either buy such (approximately 100-400:- depending on the type) or mount 45 mm stone wool in frames on the ceiling and then stretch fabric over this.
http://www.rockfon.se/
http://www.hififorum.nu/forum/topic.asp?TOPIC_ID=82455
If I were to have a dedicated sound room, I would dampen the room very heavily, more at the front end, less at the back end. Then I would probably build some BAD panels and finally experiment a bit with diffusion to possibly get the finishing touch just right.
Acoustic ceilings and prices and a lot more info can be found here:
http://bllund.se/hem
Go to "Akustikshopen.se" which is linked at the top of the page and browse a bit; the site is initially difficult to understand and navigate, but eventually, you'll find a bunch of different acoustic gadgets with accompanying prices. Also, read the general info available on these pages.
More links:
http://www.sonicdesign.se/oeint9.html
http://www.analogue.org/network/snabblektion i rumsakustik.htm
http://www.diffusor.com/Akustik.htm
http://www.linkwitzlab.com/rooms.htm
http://www.mh-audio.nl/ACalculators.asp
Furthermore, there are no absolute truths; if you ask three experts, you'll get three different opinions on how it should be.
Some people work a little "cautiously" with room acoustics, often pressured by either the budget or the room's design (and/or other usage). These rooms often end up being slightly better than completely "untreated" rooms, but far from what can be achieved if you go a bit more uncompromisingly. In this category, there’s often a dampening rug on the floor, attempts to hang suitable curtains in various spots, and finally, some bookshelf or similar in a good place.
Others work very hard with damping; I myself lean towards this category since hearing a stereo in a completely anechoic room, and I believe that in a typical living room, you can hardly dampen enough.
Others aim much more towards diffusion and want to set up irregular surfaces everywhere.
Yet another group primarily wants the reverberation times to be equal across all frequencies.
And so most people probably work with a partially combined approach of these strategies. Yes, even design often needs to be considered to some extent.
In my opinion, there are two major culprits, and one of them is often very difficult to deal with.
1. Early reflections, the first reflection against hard surfaces in the room.
2. Standing waves in the bass area, up to mid-bass depending on the room's size.
1. This is most easily addressed with damping in the right places. The right places are where you can see one of the speakers from one of the listening positions if you place a mirror against the surface. Put a thick woolly rug on the floor between the speakers and the listening area. Build frames out of 22x95mm timber, fill with mineral wool, and cover with a beautiful fabric, placing these absorbers on the walls in suitable places. Also, put one or several on the ceiling in the right place.
2. This is a tricky issue, some rooms have an enormous amount of problems with this and are difficult to resolve. One solution is Helmholz absorbers tuned to the correct frequencies (up to 3 different = the room's 3 different dimensions) placed in the corners of the room. There are also active solutions that capture sound with a microphone and play the sound back in anti-phase, thereby counteracting the standing waves. These work for all frequencies, so you don't need 3 of them.
But what you're really asking about relates to category 1. I personally am installing a Rockfon acoustic ceiling in the living room as we build; this dampens broadband down to almost 500Hz, frequencies below this I have to fix in other ways. You can either buy such (approximately 100-400:- depending on the type) or mount 45 mm stone wool in frames on the ceiling and then stretch fabric over this.
http://www.rockfon.se/
http://www.hififorum.nu/forum/topic.asp?TOPIC_ID=82455
If I were to have a dedicated sound room, I would dampen the room very heavily, more at the front end, less at the back end. Then I would probably build some BAD panels and finally experiment a bit with diffusion to possibly get the finishing touch just right.
Acoustic ceilings and prices and a lot more info can be found here:
http://bllund.se/hem
Go to "Akustikshopen.se" which is linked at the top of the page and browse a bit; the site is initially difficult to understand and navigate, but eventually, you'll find a bunch of different acoustic gadgets with accompanying prices. Also, read the general info available on these pages.
More links:
http://www.sonicdesign.se/oeint9.html
http://www.analogue.org/network/snabblektion i rumsakustik.htm
http://www.diffusor.com/Akustik.htm
http://www.linkwitzlab.com/rooms.htm
http://www.mh-audio.nl/ACalculators.asp
Here is someone who has built sound absorbers themselves.
http://www.minhembio.com/Idala
http://www.minhembio.com/Idala
Stew: The problem with the foam you show in the picture and also egg cartons, is that the structure doesn't vary. A genuine (expensive) panel has an uneven surface even though it looks similar at first glance. I have read that regular egg cartons provide about a 4% damping, so it's better than nothing, of course. You can find different types of damping materials and their values here. http://www.acousticsfirst.com/
As a diffuser, the regularly irregular surface of egg cartons and that foam is poor. You get interference and unwanted comb filter effects.
But don't forget that this foam has an incredibly poor reflection at half the wavelength of the distance between the peaks and higher frequencies, so I think it doesn’t have any noticeable negative impact. However, I also don't think those peaks contribute anything. I doubt any person in the universe could distinguish whether bumpy or smooth foam is on the wall in a blind test.
Cleverly designed foam (acoustically cleverly) can instead be constructed of wedges, allowing the small reflection that exists to bounce further inward, thus dampening more.
But don't forget that this foam has an incredibly poor reflection at half the wavelength of the distance between the peaks and higher frequencies, so I think it doesn’t have any noticeable negative impact. However, I also don't think those peaks contribute anything. I doubt any person in the universe could distinguish whether bumpy or smooth foam is on the wall in a blind test.
Cleverly designed foam (acoustically cleverly) can instead be constructed of wedges, allowing the small reflection that exists to bounce further inward, thus dampening more.
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Hello again,
Still thinking about this. I'm considering the idea of building boxes with fiberglass, which would then be covered with fabric.
Can it be taken a step further by insulating the room from the inside, building up with cc120 studs, inserting insulation panels of 45mm (http://www.byggmax.com/se-sv/prod/pid-16237.aspx). Cover this with fabric. For example, http://www.biltema.se/sv/Bil---MC/Bil-tillbehor/Styling/Interior/Hogtalarmatta/ or something nicer.
Would this achieve the desired effect?
The current state is that I have a concrete room, uninsulated, metal studs, OSB + drywall. The worst possible room for sound reproduction
Best regards,
Stefan
Still thinking about this. I'm considering the idea of building boxes with fiberglass, which would then be covered with fabric.
Can it be taken a step further by insulating the room from the inside, building up with cc120 studs, inserting insulation panels of 45mm (http://www.byggmax.com/se-sv/prod/pid-16237.aspx). Cover this with fabric. For example, http://www.biltema.se/sv/Bil---MC/Bil-tillbehor/Styling/Interior/Hogtalarmatta/ or something nicer.
Would this achieve the desired effect?
The current state is that I have a concrete room, uninsulated, metal studs, OSB + drywall. The worst possible room for sound reproduction
Best regards,
Stefan
It makes a big difference. You will achieve a very high absorption rate on reflections down to 500Hz or lower.stew said:
To reach the lowest frequencies (as well as possible) you should increase the thickness of the insulation boards, the density of the insulation boards, and have a larger gap behind the boards.
The fabric you put in front isn't as crucial, but not too tightly woven or glossy can be good to avoid less absorption in the very highest frequencies.
But to maximize, you may want to space out with 25-40 cm or so (doesn't need to be solid studs at all and can rather stand on some form of "support"), then have a heavy insulation, such as ground insulation, say 10cm.
However, it is not certain that this last step is worthwhile, because you still won't get enough absorption for the really low frequencies.
So in your clothes, I would probably go with what you suggested and then try to combat the most low frequency with other methods, such as HH-absorbers or active standing wave eaters.
In my case, the next step would then be to try to determine how large parts of the room to fully dampen, and which parts.
I would build a bit at a time and try to determine when I have reached a good level. And I would start primarily with sidewalls and the ceiling, possibly a carpet on the floor.
Personally, I believe in a lot of damping, but there are clearly different schools.
A little measuring equipment is golden too.
For example, the XTZ room analyzer is used quite a lot and also provides information about reverberation times.
edit:
http://www.xtz.se/se/produkter/mjukvara/room-analyzer?stat=1
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Thanks again Mikael, you are a constant source of wisdom!
Ok. I'll think a bit more about this.
I also plan to install crosswise (from the perspective of the front speakers) 45x45mm (heeled) battens in the ceiling. I haven't really checked the distance between them, maybe around 20cm. This should deal with the sound waves quite well, right? The ceiling will be painted black afterward.
Furthermore, I was thinking of a really luscious red wall-to-wall carpet for the floor. This should also help with the damping, right?
By the way, I found what I was looking for in my initial question:
http://www.biltema.se/sv/Bil---MC/Bilstereo/Monteringsdetaljer/Dampmaterial-till-hogtalare-5-st1/
Egg carton foam plastic.
However, this one doesn't seem to be anywhere near the real ones. Very thin, light, and "uniform". A real mat looks like it has small variations across it. Probably (and hopefully) what justifies the 20 times higher price.
Ps. I noticed that I wrote fiberglass up there. It was too fast when I wrote that, I mean insulation board of mineral/glass wool. Ds.
Ok. I'll think a bit more about this.
I also plan to install crosswise (from the perspective of the front speakers) 45x45mm (heeled) battens in the ceiling. I haven't really checked the distance between them, maybe around 20cm. This should deal with the sound waves quite well, right? The ceiling will be painted black afterward.
Furthermore, I was thinking of a really luscious red wall-to-wall carpet for the floor. This should also help with the damping, right?
By the way, I found what I was looking for in my initial question:
http://www.biltema.se/sv/Bil---MC/Bilstereo/Monteringsdetaljer/Dampmaterial-till-hogtalare-5-st1/
Egg carton foam plastic.
However, this one doesn't seem to be anywhere near the real ones. Very thin, light, and "uniform". A real mat looks like it has small variations across it. Probably (and hopefully) what justifies the 20 times higher price.
Ps. I noticed that I wrote fiberglass up there. It was too fast when I wrote that, I mean insulation board of mineral/glass wool. Ds.
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