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Bass traps in room

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Re: Bass traps in room

Postby Sam Spoons » Thu Oct 17, 2019 9:53 pm

Corner traps are called that 'cos, as you guessed, they are designed to fit in corners. If you can't do that (why not?) then the deepest flat panels spaced as far off the surface as possible will absorb the lowest frequencies.

But, a 4"/100mm deep panel placed against a surface will do little below about 600Hz, corner traps increase the distance the sound energy has to travel before emerging so a 12"/300mm deep corner trap will have some useful effect down to 250 Hz or so.

HTH
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Re: Bass traps in room

Postby Danny_79 » Thu Oct 17, 2019 10:20 pm

blinddrew wrote:Yep, the first ones of your pair of links are for flat wall placement, the second link for corners. They're only foam so won't be heavy, what to attach them with will depend on your wall finish but an appropriate glue might do the job (or glue some velcro on then staple a bit of velcro to the wall - that way you've only got a couple of tiny holes to fill if you need to move or remove them.) Worth checking with the manufacturer on an appropriate glue first though.
Found another 2 that kinda confuses me even more :lol:
https://www.thomann.de/se/the_takustik_ac37.htm
https://www.thomann.de/se/hofa_basstrap ... _stock.htm
I guess the ones in the first link are perhaps made for corners, but the second link...i have no idea
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Re: Bass traps in room

Postby Danny_79 » Thu Oct 17, 2019 10:26 pm

CS70 wrote:Btw, diffusers tend to look like these (there's also other forms but these are common)

They are useful for higher frequency ringing, and are nice to look at, but be aware, massive wood ones weight a lot. I had 6 made for my wall, but wasn't aware each 55x55 panel was 16Kg... I even bought super heavy duty anchors from the US before looking at my drywall and thinking "nah". So I resold them.

Image

Image

I don't see any such in that picture/illustration on the first page of the thread....does that mean diffusers arn't always used?
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Re: Bass traps in room

Postby Danny_79 » Thu Oct 17, 2019 10:40 pm

Sam Spoons wrote:Corner traps are called that 'cos, as you guessed, they are designed to fit in corners. If you can't do that (why not?) then the deepest flat panels spaced as far off the surface as possible will absorb the lowest frequencies.

But, a 4"/100mm deep panel placed against a surface will do little below about 600Hz, corner traps increase the distance the sound energy has to travel before emerging so a 12"/300mm deep corner trap will have some useful effect down to 250 Hz or so.

HTH
The problems when it comes to my corners are: In one of them there is a valve close to the ceiling, and a power outlet close to the floor. In another there is a water pipe from the heater going very close to the corner. And the corner closest tom my monitors...there is a curtain near the ceiling. And it's so close to where i walk into the kitchen that i would probably collide with the trap when i walk there if it's placed further down. In 2 of the corners, traps could be placed in the middle between floor and ceiling. But those corners are further away, so i don't know if that would do much good(?) This room is really badly built regarding acoustic treatment :lol: I'm only talking about the kind of corners where two walls meet tho...
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Re: Bass traps in room

Postby Sam Spoons » Fri Oct 18, 2019 9:46 am

Corner traps don't need to be between two walls, floor/wall and ceiling/wall corners are equally as beneficial. Even quite large gaps behind the traps (to accommodate the heating pipe for example) will only reduce the effectiveness a little and positioning of bass traps is less critical as the wavelength of bass frequencies is more than the length of a typical domestic room (low E on a bass has a wavelength of around 8.6 metres). That is what makes it so hard to control but it does mean bass traps placed anywhere in the room will have a useful effect.
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Re: Bass traps in room

Postby Luke W » Fri Oct 18, 2019 10:20 am

Danny_79 wrote:I don't see any such in that picture/illustration on the first page of the thread....does that mean diffusers arn't always used?

They tend to be less useful in smaller rooms where it's usually more beneficial to use absorption to reduce/remove reflections rather than trying to control them.

I think it's also quite difficult to get genuinely useful diffusion, but my knowledge is pretty limited where acoustics are concerned.
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Re: Bass traps in room

Postby Danny_79 » Fri Oct 18, 2019 7:39 pm

Luke W wrote:
Danny_79 wrote:I don't see any such in that picture/illustration on the first page of the thread....does that mean diffusers arn't always used?

They tend to be less useful in smaller rooms where it's usually more beneficial to use absorption to reduce/remove reflections rather than trying to control them.

I think it's also quite difficult to get genuinely useful diffusion, but my knowledge is pretty limited where acoustics are concerned.
My room is small so perhaps diffusers could be useful. Where would you put them?
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Re: Bass traps in room

Postby Danny_79 » Fri Oct 18, 2019 7:51 pm

Sam Spoons wrote:Corner traps don't need to be between two walls, floor/wall and ceiling/wall corners are equally as beneficial. Even quite large gaps behind the traps (to accommodate the heating pipe for example) will only reduce the effectiveness a little and positioning of bass traps is less critical as the wavelength of bass frequencies is more than the length of a typical domestic room (low E on a bass has a wavelength of around 8.6 metres). That is what makes it so hard to control but it does mean bass traps placed anywhere in the room will have a useful effect.
I see....then it suddenly became less tricky :)
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Re: Bass traps in room

Postby CS70 » Fri Oct 18, 2019 8:29 pm

Danny_79 wrote:I don't see any such in that picture/illustration on the first page of the thread....does :boring: that mean diffusers arn't always used?

They're complementary, but if you have absorption enough, there's very little to diffuse :D

Diffusers break "ringing" or flutter echo: which is reflection bouncing between between parallel walls (or even more often ceiling and floor, especially with hardwood floor). You hear it clearly if it exists in a room if, when you clap your hand, you hear a short faint echo (in a large hall, you would hear a lot of repetitions).

They scatter the sound wave in a randomized manner, so that while (unlike absorbers) the energy level is not reduced much, it no longer has a recognizable relationship with the original sound - basically it becomes reverberation. The echos that can be diffused by a panel are mostly mid/high frequency.

You use absorbers when you want to get a "dry" room, while you use diffusers when you want to keep more reverberation. In recording rooms there's often absorbers and diffusers because a degree of (random) reverb is good, but with dedicated mixing station, you really want the mixing position to be as dry as possible.
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Re: Bass traps in room

Postby Danny_79 » Sat Oct 19, 2019 2:22 pm

CS70 wrote:
Danny_79 wrote:I don't see any such in that picture/illustration on the first page of the thread....does :boring: that mean diffusers arn't always used?

They're complementary, but if you have absorption enough, there's very little to diffuse :D

Diffusers break "ringing" or flutter echo: which is reflection bouncing between between parallel walls (or even more often ceiling and floor, especially with hardwood floor). You hear it clearly if it exists in a room if, when you clap your hand, you hear a short faint echo (in a large hall, you would hear a lot of repetitions).

They scatter the sound wave in a randomized manner, so that while (unlike absorbers) the energy level is not reduced much, it no longer has a recognizable relationship with the original sound - basically it becomes reverberation. The echos that can be diffused by a panel are mostly mid/high frequency.

You use absorbers when you want to get a "dry" room, while you use diffusers when you want to keep more reverberation. In recording rooms there's often absorbers and diffusers because a degree of (random) reverb is good, but with dedicated mixing station, you really want the mixing position to be as dry as possible.
Learning alot of new stuffs in this thread... I might be confusing diffusers with something else here. I was thinking of a material that absorbs mid and high freq sound. Sorta like a bass trap but meant for higher freqs. I thought it was diffusers
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Re: Bass traps in room

Postby Hugh Robjohns » Sat Oct 19, 2019 3:17 pm

Danny_79 wrote:I might be confusing diffusers with something else here. I was thinking of a material that absorbs mid and high freq sound. Sorta like a bass trap but meant for higher freqs. I thought it was diffusers

Nope, diffusers dont absorb, they scatter sound.

What you're describing are simply mid- and HF-absorbers. Although these can be separate units, it's more common to use 'broadband absorbers' which soak up both mid and high frequencies. Typically, these are made using acoustic foam or mineral-wool in panels of between 2 and 4 inches depth.
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Re: Bass traps in room

Postby Sam Spoons » Sat Oct 19, 2019 6:11 pm

CS70 wrote:Image

i.e. pretty much all the panels in CS70's earlier pic (above).

The ones across the corners will have some effect down to lower frequencies for reasons discussed up the thread.
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Re: Bass traps in room

Postby Danny_79 » Sat Oct 19, 2019 8:01 pm

Cheers to everyone who answered here! :thumbup: Learned alot.
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Re: Bass traps in room

Postby Danny_79 » Sat Oct 19, 2019 8:05 pm

Hugh Robjohns wrote:
Danny_79 wrote:I might be confusing diffusers with something else here. I was thinking of a material that absorbs mid and high freq sound. Sorta like a bass trap but meant for higher freqs. I thought it was diffusers

Nope, diffusers dont absorb, they scatter sound.

What you're describing are simply mid- and HF-absorbers. Although these can be separate units, it's more common to use 'broadband absorbers' which soak up both mid and high frequencies. Typically, these are made using acoustic foam or mineral-wool in panels of between 2 and 4 inches depth.

Ok...Judging from the picture of the room earlier in the thread, i'm guessing they are installed and treated in a simmillar manner as bass traps(?) I mean, theyr'e both absorbers after all. But the broadband ones seems more to the walls and not in corners tho
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Re: Bass traps in room

Postby Sam Spoons » Sat Oct 19, 2019 8:16 pm

Broad band absorbers covering low mids upwards in a mixing room are usually fitted parallel to a wall or ceiling at the 'mirror points'. To make most efficient use of materials and space they are best spaced off the surface. They don't need the depth of bass traps (the deeper the traps are the lower the frequency they can absorb).

In my 4m x 4m room I have seven 50mm thick panels spaced (mostly) 50mm off the surface. Most are 1200mm x 600mm area. In addition I have two corner traps and a large 10" deep trap behind the monitors (can't post a picture but link below). The difference between the untreated room and with £300 spent on DIY panels is night and day, time and money very well spent.

https://www.dropbox.com/preview/Studio%20Refurb/Studio%20Finished.JPG?role=personal
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Re: Bass traps in room

Postby Danny_79 » Mon Oct 21, 2019 7:38 pm

Sam Spoons wrote:Broad band absorbers covering low mids upwards in a mixing room are usually fitted parallel to a wall or ceiling at the 'mirror points'. To make most efficient use of materials and space they are best spaced off the surface. They don't need the depth of bass traps (the deeper the traps are the lower the frequency they can absorb).

In my 4m x 4m room I have seven 50mm thick panels spaced (mostly) 50mm off the surface. Most are 1200mm x 600mm area. In addition I have two corner traps and a large 10" deep trap behind the monitors (can't post a picture but link below). The difference between the untreated room and with £300 spent on DIY panels is night and day, time and money very well spent.

https://www.dropbox.com/preview/Studio%20Refurb/Studio%20Finished.JPG?role=personal
When i click the link, the site says i have to create an account to see what's there...anyway, any suggestions on how to attach absorbers away from the surface to leave air behind them? In the ceiling, you could drill holes and put hooks there, like in that picture. But on the wall...using long nails or something?
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Re: Bass traps in room

Postby blinddrew » Mon Oct 21, 2019 9:35 pm

Knock up some mounting blocks of a suitable size, say 2" cubes, mount those to the walls with rawl plugs and screws. On the back of the foam (if you go that route) glue some old cds (large surface area, low weight), put a small locating screw into the blocks. Hook cd centre holes over locating screws.
Does that make sense?
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Re: Bass traps in room

Postby Danny_79 » Wed Oct 23, 2019 7:35 pm

blinddrew wrote:Knock up some mounting blocks of a suitable size, say 2" cubes, mount those to the walls with rawl plugs and screws. On the back of the foam (if you go that route) glue some old cds (large surface area, low weight), put a small locating screw into the blocks. Hook cd centre holes over locating screws.
Does that make sense?

Yeah... i think so :thumbup: Back to corner bass traps again...given how they're formed, they should not be spaced of the surface like other absorbers should. Am i right?
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Re: Bass traps in room

Postby Sam Spoons » Wed Oct 23, 2019 8:18 pm

Corner traps are fine with a space behind and slightly better with none, just go with the biggest area at the front, biggest depth overall and whatever fits behind.
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Re: Bass traps in room

Postby Danny_79 » Thu Oct 24, 2019 9:43 pm

I found something(link below) meant to absorb mid and high frequencies. So i suppose it's some kind of broadband absorber. Can anyone tell me a good place to install them, and why they are shaped the way they are? Does the shape have anything to do with leaving space behind them or something? I mean, they don't look like the broadband absorbers in that shared picture in this thread. So i don't know if the same "rules" applies to them. https://www.thomann.de/se/eq_acoustics_ ... e_grey.htm
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