#1647375 - 03/31/04 04:52 PM
Apex ceiling again
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cany
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Registered: 03/05/04
Posts: 13
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Hi Ethan I took your advice from my previous thread and constructed low bass taps which have helped a lot.The thing is,is at the listening position there seems to be a suckout in the bass but when I stand in the same position the bass re appears.I have a flat area at the top of my apex ceilng if I put traps there do you think this might sort it?Im not very technical in thes matters but the suckout sounds like there is no bass drum sitting but there is a bass drum when I stand.
Many Thanks Iain
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#1647376 - 03/31/04 06:48 PM
Re: Apex ceiling again
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Ethan Winer
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Registered: 06/12/00
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Loc: New Milford, CT, USA
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Iain,
> at the listening position there seems to be a suckout in the bass <
Then you still need more traps.
> I have a flat area at the top of my apex ceilng if I put traps there do you think this might sort it? <
You really need them near corners. If there are corners up there, then that's a good place for them. But before you build anything further, tell me more about your room. How big is it? How many traps did you make already, and what type? Where are your speakers placed, and where do you sit in relation to the walls, etc?
--Ethan
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#1647377 - 04/01/04 12:39 PM
Re: Apex ceiling again
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cany
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Registered: 03/05/04
Posts: 13
Loc: england
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Hi Ethan
The room is 19x15ft the walls rise vertically 3ft then all 4 walls slant inwards to form a kind of pyramid shape.There is a rectangular flat peice of ceiling approx 4x10ft at the top of the slopey walls this is where my bass drum is.I have deep bass traps all along one of the 19x3ft walls and half way along the other as this is where the stairs come in.On 3 of the slopey walls ihave panels of 2 inch 703. I could change these to bass traps if needed.With regards to speaker and listener positions they can be anywhere and the bass drum is in the ceiling.
Cheers Iain.
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#1647378 - 04/01/04 02:12 PM
Re: Apex ceiling again
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Ethan Winer
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Posts: 5405
Loc: New Milford, CT, USA
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Iain,
> I have deep bass traps all along one of the 19x3ft walls and half way along the other <
Are you saying you built the wood panel traps from my plans, but built only the low-bass type and none of the high-bass ones? If so, that's a big problem! As explained in my original article, you need both types of traps.
> the bass drum is in the ceiling <
I don't know what that means.
In any case, you need a mix of low-bass and high-bass traps, and also some plain rigid fiberglass. You can certainly put more rigid fiberglass across the various corners, including the ceiling corners. That can substitute for building high-bass panel traps, especially if the fiberglass is thick enough. You need it to be at least two inches thick, and four is better still.
--Ethan
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#1647379 - 04/01/04 02:37 PM
Re: Apex ceiling again
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cany
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Registered: 03/05/04
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Loc: england
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Hi Ethan
I built the deep bass traps from your plans.I didnt build any high bass traps because I assumed that the 2inch panels of 703 on the slopey walls would take care of that.Sorry when I said the bass drum is in the ceiling what I meant was regardless of speaker positioning and listener position there is suckout at seated height and the bass drum only comes back when Im standing.
Cheers Iain
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#1647380 - 04/01/04 03:56 PM
Re: Apex ceiling again
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Ethan Winer
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Loc: New Milford, CT, USA
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Iain,
> I didnt build any high bass traps because I assumed that the 2inch panels of 703 on the slopey walls would take care of that. <
Rigid fiberglass can replace the high-bass traps, but not if it's only two inches thick and mounted flat on the wall with no air gap.
--Ethan
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#1647381 - 04/01/04 04:21 PM
Re: Apex ceiling again
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cany
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Hi Ethan
My panels are 2inches thick on a flat wall.Please tell me what I should do.
Cheers Iain.
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#1647382 - 04/01/04 05:11 PM
Re: Apex ceiling again
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Andre Vare
Senior Member
Registered: 03/13/04
Posts: 125
Loc: Hamilton, ON Canada
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I didnt build any high bass traps because I assumed that the 2inch panels of 703 on the slopey walls would take care of that.
My panels are 2inches thick on a flat wall.Please tell me what I should do.
Number two is get the material 4"(100mm) thick.
Number three, and this cheap, use the various romm mode calculators on the web to see what the problem frequencies are. Then look at the various absorption rates of different materials to see what helps you. There are many sources for the absorption data available on the net.
Good luck!
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#1647383 - 04/01/04 06:43 PM
Re: Apex ceiling again
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cany
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Hi Andre
Thanks for your reply.I was under the impression that 2 inches of 703 will absorb down to 250hz therefore making high bass traps unnecessary please correct me if I am wrong
Cheers Iain.
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#1647384 - 04/01/04 07:32 PM
Re: Apex ceiling again
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Andre Vare
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Registered: 03/13/04
Posts: 125
Loc: Hamilton, ON Canada
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Thanks for your reply.I was under the impression that 2 inches of 703 will absorb down to 250hz therefore making high bass traps unnecessary please correct me if I am wrong
2" 703 or any 3lb^3 material will be effective down to 250Hz in free field absorption. It will only be effective, meaning 1 to about 500Hz in normal absorption. The problem as I am reading from your posts, is below that frequency.
Place more material where the room modes are most effective for the material.
Have fun!
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#1647385 - 04/02/04 03:53 AM
Re: Apex ceiling again
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cany
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Registered: 03/05/04
Posts: 13
Loc: england
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Andre
Do you mean place more material where there is bass boom?
Cheers Iain.
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#1647386 - 04/02/04 09:02 AM
Re: Apex ceiling again
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Andre Vare
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Registered: 03/13/04
Posts: 125
Loc: Hamilton, ON Canada
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Please provide more information. What is the size of your room? Where do you have the absorbtive material now? How much do you have?
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#1647387 - 04/02/04 10:42 AM
Re: Apex ceiling again
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cany
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Loc: england
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Hi Andre
The room is described further up this tthread
Cheers Iain.
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#1647388 - 04/02/04 11:39 AM
Re: Apex ceiling again
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Ethan Winer
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Registered: 06/12/00
Posts: 5405
Loc: New Milford, CT, USA
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Iain,
> I was under the impression that 2 inches of 703 will absorb down to 250hz <
"Absorb down to" is relative. The low-bass traps are centered around 100 Hz and the high-bass types are at about 180 Hz. Each absorbs over a range of about an octave. So you really need to add absorption between about 150 and 300 Hz.
--Ethan
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#1647389 - 04/02/04 12:09 PM
Re: Apex ceiling again
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cany
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Registered: 03/05/04
Posts: 13
Loc: england
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Hi Ethan
So it would fair to say that if I build some high bass traps that this would be the way to go.
Cheers Iain
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#1647390 - 04/02/04 02:04 PM
Re: Apex ceiling again
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Ethan Winer
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Registered: 06/12/00
Posts: 5405
Loc: New Milford, CT, USA
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> So it would fair to say that if I build some high bass traps that this would6250the way to go. <
Yes.
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#1647391 - 04/02/04 03:08 PM
Re: Apex ceiling again
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cany
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Registered: 03/05/04
Posts: 13
Loc: england
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 Thanks
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