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Bass traps in room

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Bass traps in room

Postby Danny_79 » Tue Oct 15, 2019 7:23 pm

Hey! I have in mind to treat my room with some pretty large sized bass traps. The problem is, they can't be placed very close to the roof, nor the floor, in any of my corners. There are things in the way. Power outlets, blow-hole/valve, furniture etc...you get the point ;) However, there are 2 of the corners where they could be installed somewhere between floor and roof. And i could install them very close to corners as well. But would this make any difference, or would it be waste of money? In short: Will bass traps do me good even if they can't be placed at the best spots? I know i can't get the sound of a professionaly built studio, but if there are ways to improve the sound a little despite the limitations of my room, i'm all ears.
Hit me with any suggestions!
This is all for the sake of listening to mixes through monitors in my room, so i assumed the thread belongs in this forum section...
Thanx
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Re: Bass traps in room

Postby blinddrew » Tue Oct 15, 2019 10:02 pm

Bass traps will work best in triple corners but they will almost certainly help in double corners as well.
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Re: Bass traps in room

Postby CS70 » Tue Oct 15, 2019 10:43 pm

Danny_79 wrote:In short: Will bass traps do me good even if they can't be placed at the best spots?

Absolutely. What you want to avoid are reflections coming back at your mixing station.

Since bass waves have a wavelength in meters, comparable to the walls size, they bounce everywhere quickly: sides, floor and ceiling (visualize an half sphere in 3D whose radius is in meters). When the sphere touches a bass traps, it the portion of the surface which does, stops there (more or less.. but lets not go into details) .

In a corner, a trap can stop bounces from three sides in one go, which is why it's effective. But it still stops them also in other positions.

Ideally you would want that the wave meets a trap no matter where it goes before hitting the wall, or alternatively that the reflection hits it before it reaches your ears.

Obviously doing that is hard, unless you surround the entire mixing station with bass trapping :D . But that explains why with bass traps it's an issue of quantity more than position. And also why. unless you build the entire walls to be absorbent, some reflections will always come back to your ears and comb filter a little, and you will always have some standing waves so long the speakers produce low freq waves often enough.

It also helps with a larger room, as energy dissipates with the square of the distance.. but that's usually the big problem in regular homes.

I know i can't get the sound of a professionaly built studio, but if there are ways to improve the sound a little despite the limitations of my room, i'm all ears.

For mixing, what matters is the position at your station. Placing the traps relatively near (like on the ceiling over you and on the immediate sides of the monitors, and behind) helps because you're gonna clean up much of the volume nearby. If you place them not against the wall, they will have a chance to absorb both the direct sound and whatever energy that passes thru and reflects, so if possible it's good to leave some good layer of air behind them.
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Re: Bass traps in room

Postby Danny_79 » Wed Oct 16, 2019 8:56 pm

[quote="
For mixing, what matters is the position at your station. Placing the traps relatively near (like on the ceiling over you and on the immediate sides of the monitors, and behind) helps because you're gonna clean up much of the volume nearby. If you place them not against the wall, they will have a chance to absorb both the direct sound and whatever energy that passes thru and reflects, so if possible it's good to leave some good layer of air behind them.[/quote]

Thanx for some interesting tips m8. Do you mean on the ceiling straight above me or to the wall? I've seen some people who place them at the ceiling and the wall.

I haven't learned how to use the quote function properly. Not when i want to quote pieces of text :lol:
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Re: Bass traps in room

Postby CS70 » Wed Oct 16, 2019 9:01 pm

Danny_79 wrote:Thanx for some interesting tips m8. Do you mean on the ceiling straight above me or to the wall? I've seen some people who place them at the ceiling and the wall.


Exactly :D The more the merrier. So ideally you place them both over you and to the side walls a little more towards the near wall (the one you're facing) with respect the imaginary vertical plane connecting the center of the speakers. But if you can put one also behind the speakers, they will too help absorb reflections which will otherwise bounce back near your ears.

This pic from GIK Acoustics shows a possible configuration (note also the air spaces behind the traps):

Image
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Re: Bass traps in room

Postby Sam Spoons » Wed Oct 16, 2019 9:09 pm

you need a [ and ] at each end of the quote or /quote.

Bass traps will work wherever you put them but their effectiveness is increased if in a corner, imagine them at the centre of a sphere, if you stick one on a wall it will double the amount of absorption as it is only handling sound from a hemisphere, in a single corner (like between two walls) will quadruple effectiveness cos it's only has to absorb sound from ¼ of a sphere and a three way corner (walls and ceiling or floor) will double it again. It's the analogue of speaker placement, stick one in a corner (especially a sub as the effect is wavelength dependent) and it will be louder at the low end (which is why many wedge shaped tops have a 'monitor' position eq switch which reduces the bass if on the floor).

edit :- great minds (or fools never differ) CS :bouncy:
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Re: Bass traps in room

Postby Danny_79 » Wed Oct 16, 2019 9:41 pm

CS70 wrote:
Danny_79 wrote:Thanx for some interesting tips m8. Do you mean on the ceiling straight above me or to the wall? I've seen some people who place them at the ceiling and the wall.


Exactly :D The more the merrier. So ideally you place them both over you and to the side walls a little more towards the near wall (the one you're facing) with respect the imaginary vertical plane connecting the center of the speakers. But if you can put one also behind the speakers, they will too help absorb reflections which will otherwise bounce back near your ears.

This pic from GIK Acoustics shows a possible configuration (note also the air spaces behind the traps):

Image

I think the tricky(or impossible) part will be to leave air behind them :lol: But i see what you mean :thumbup:
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Re: Bass traps in room

Postby Sam Spoons » Wed Oct 16, 2019 10:59 pm

You can use deep traps (which will absorb low frequencies better) or you can space them off he wall/ceiling a little which will work almost as well. I have both in my room. But, do what you can, it will improve the acoustics. If you can't do it then accept the compromise and you'll still have a better sounding room than if you'd decided it was an impossible task.
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Re: Bass traps in room

Postby CS70 » Wed Oct 16, 2019 11:13 pm

Sam is on the money. Something is better than nothing!

Best of luck
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Re: Bass traps in room

Postby Danny_79 » Thu Oct 17, 2019 6:41 pm

Sam Spoons wrote:You can use deep traps (which will absorb low frequencies better) or you can space them off he wall/ceiling a little which will work almost as well. I have both in my room. But, do what you can, it will improve the acoustics. If you can't do it then accept the compromise and you'll still have a better sounding room than if you'd decided it was an impossible task.
As you'll notice, i'm quite new to acoustic room treatment. What are deep traps? A special kind of bass trap or something?
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Re: Bass traps in room

Postby Danny_79 » Thu Oct 17, 2019 6:49 pm

Danny_79 wrote:
CS70 wrote:
Danny_79 wrote:Thanx for some interesting tips m8. Do you mean on the ceiling straight above me or to the wall? I've seen some people who place them at the ceiling and the wall.


Exactly :D The more the merrier. So ideally you place them both over you and to the side walls a little more towards the near wall (the one you're facing) with respect the imaginary vertical plane connecting the center of the speakers. But if you can put one also behind the speakers, they will too help absorb reflections which will otherwise bounce back near your ears.

This pic from GIK Acoustics shows a possible configuration (note also the air spaces behind the traps):

Image

I think the tricky(or impossible) part will be to leave air behind them :lol: But i see what you mean :thumbup:

About that picture....are they all bass traps or are there other stuffs like diffusers as well? I know even less about them, but i've got the impression that real studios will use them to.
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Re: Bass traps in room

Postby Wonks » Thu Oct 17, 2019 6:50 pm

Just traps with a lot of depth e.g. 200mm of rockwool instead of 100mm.

But spacing any trap away from a wall means they work better. At the room node frequencies (where you get the worst resonance and nulls occurring) the pressure/ wave movement is at/close to zero, so putting absorbing material there means that minimal absorption occurs close to the wall. So if you move your trap away from the wall, it becomes much more effective because it's now in an area where there's far more movement of the sound wave, so more energy to absorb.
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Re: Bass traps in room

Postby Sam Spoons » Thu Oct 17, 2019 6:57 pm

Danny_79 wrote:
Sam Spoons wrote:You can use deep traps (which will absorb low frequencies better) or you can space them off he wall/ceiling a little which will work almost as well. I have both in my room. But, do what you can, it will improve the acoustics. If you can't do it then accept the compromise and you'll still have a better sounding room than if you'd decided it was an impossible task.
As you'll notice, i'm quite new to acoustic room treatment. What are deep traps? A special kind of bass trap or something?

No, sorry, just thicker absorbing layers, my main 'broad band absorbers' have 50mm thick Rockwool RW3 spaced 50mm off the surface, the corner bass traps use the same material cut into triangles which extends all the way into the corner. The big bass trap is 200mm deep and has a small air gap behind.

A 50mm absorber spaced 50mm off the surface is nearly as effective as a 100mm absorber with no gap behind, deeper traps work down to lower frequencies but, in a small room, none are going to be really effective at 'proper' bass frequencies (though it all helps).

To get really effective bass trapping you need to look at 'Hermholtz resonators' or 'limp mass membranes' built into the design which is way beyond my knowledge and much harder to DIY.

In that pic above are broad band absorbers, the ones placed across the ceiling/wall corner will work further into the bass end due to the large gap behind, making them full depth would probably improve their effectiveness but I'm not sure how much (it would certainly do no harm).
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Re: Bass traps in room

Postby Wonks » Thu Oct 17, 2019 7:05 pm

Image

The dark blue ones will be the most effective bass traps as they are in corners/where two or more surfaces meet. Not sure whether light blue are just fabric panels or part of a really deep corner bass trap, Green ones are broadband absorbers and are quite deep, so will absorb some upper bass.

Orange is the ceiling cloud. Broadband and some decent bass absorption due to a good spacing away from the ceiling
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Re: Bass traps in room

Postby Danny_79 » Thu Oct 17, 2019 7:11 pm

Wonks wrote:Just traps with a lot of depth e.g. 200mm of rockwool instead of 100mm.

But spacing any trap away from a wall means they work better. At the room node frequencies (where you get the worst resonance and nulls occurring) the pressure/ wave movement is at/close to zero, so putting absorbing material there means that minimal absorption occurs close to the wall. So if you move your trap away from the wall, it becomes much more effective because it's now in an area where there's far more movement of the sound wave, so more energy to absorb.
I see....some traps are called "corner bass traps" and some are just called bass traps. Is that all about how they are formed, or should one choose depending on where they are to be installed?
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Re: Bass traps in room

Postby Danny_79 » Thu Oct 17, 2019 7:53 pm

Found 2 different types which i will have to choose between: https://www.thomann.de/se/ultimate_acou ... a_btbv.htm
https://www.thomann.de/se/the_t.akustik_cbt_37.htm

I suppose it depends on where i wish to install them, yes?
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Re: Bass traps in room

Postby Danny_79 » Thu Oct 17, 2019 8:04 pm

Sam Spoons wrote:
Danny_79 wrote:
Sam Spoons wrote:You can use deep traps (which will absorb low frequencies better) or you can space them off he wall/ceiling a little which will work almost as well. I have both in my room. But, do what you can, it will improve the acoustics. If you can't do it then accept the compromise and you'll still have a better sounding room than if you'd decided it was an impossible task.
As you'll notice, i'm quite new to acoustic room treatment. What are deep traps? A special kind of bass trap or something?

No, sorry, just thicker absorbing layers, my main 'broad band absorbers' have 50mm thick Rockwool RW3 spaced 50mm off the surface, the corner bass traps use the same material cut into triangles which extends all the way into the corner. The big bass trap is 200mm deep and has a small air gap behind.

A 50mm absorber spaced 50mm off the surface is nearly as effective as a 100mm absorber with no gap behind, deeper traps work down to lower frequencies but, in a small room, none are going to be really effective at 'proper' bass frequencies (though it all helps).

To get really effective bass trapping you need to look at 'Hermholtz resonators' or 'limp mass membranes' built into the design which is way beyond my knowledge and much harder to DIY.

In that pic above are broad band absorbers, the ones placed across the ceiling/wall corner will work further into the bass end due to the large gap behind, making them full depth would probably improve their effectiveness but I'm not sure how much (it would certainly do no harm).

Cheers m8! I think this message answered a few things. If i want them on the wall, i should probably not go for the triangle formed ones. Since they seem more made for corners. But the other ones(first of my links above), about how heavy are they? what would you use to attach them to the wall and/or the ceiling?
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Re: Bass traps in room

Postby blinddrew » Thu Oct 17, 2019 9:04 pm

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.
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Re: Bass traps in room

Postby Wonks » Thu Oct 17, 2019 9:20 pm

But foam isn't the best material for bass traps. You could get more bass absorption in the same space with better materials. It's better than nothing, and it's neat and quick, but it's not optimal.
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Re: Bass traps in room

Postby CS70 » Thu Oct 17, 2019 9:23 pm

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.

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Image
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