Bass Trap Design??

Tukkis

Tukkis

New member
I was looking at Ethans bass traps and I was wondering why do they have plywood fronts?

Does the thickness of the plywood determine the frequency?

Does the fiberglass have to have an air gap on each side?

What's the difference between Ethans bass traps and high/mid absorbers material wise?

Thanks
Tukkis
 
Tukkis,

> why do they have plywood fronts? <

The plywood is a resonating membrane. When combined with the springiness of the air inside the box, the two create a filter that is not unlike a car shock absorber.

> Does the thickness of the plywood determine the frequency? <

Yes, the thickness of the plywood and also the depth of the sealed box.

> Does the fiberglass have to have an air gap on each side? <

No, just put it close to the rear of the plywood, but without touching.

> What's the difference between Ethans bass traps and high/mid absorbers material wise? <

The membrane trap works as described above, and the mid/high absorber is fiberglass only and absorbs mostly midrange and high frequencies.

--Ethan
 
Ok so it's only the depth that determines the frequency not the height or width.

Do they have to be floor to ceiling? Can they be angled so I can put them in a corner?

I have a wall 15ft long x 7.5ft high. I read on your site that it's best to put the bass panels in the corners and then alternate with the high/mids.

Can I adjust the width of the panels so I don't have to make as many or do they have to be that size?

Is having 2 panels at 2' x 8' better than 1 at 4' x 8'?

In your design it say's 1" rigid fiberglass. Is 1" enough for lows?

Thanks Heaps
Tukkis;)
 
One other thing, I noticed on your real traps site your low and high bass absorbers have an angled front panel to stop flutter echoes.

When I made mine could I angle them to achieve the same effect?
If so how much of an angle is needed?

Thanks again
Tukkis

p.s.- If I lived in the US I would buy your panels from real traps. Unfortunately I don't so I have to make my own. Thanks again for all your help.;)
 
Tukkis,

> Do they have to be floor to ceiling? <

No, but it's better that way. The goal with all bass trapping is to cover as much of the room's surface as possible. If you cover 30% of the surfaces with traps you'll get better results than if you cover only 5%. So building them shorter only makes the trapping less efficient.

> Can they be angled so I can put them in a corner? <

Yes, but you're much better off putting two traps flat on the walls in each corner since, again, that gives more surface coverage.

> Can I adjust the width of the panels so I don't have to make as many or do they have to be that size? <

You probably can vary the width, though I've never done that so I can't say for sure what might happen. But I wouldn't change it too much. If you make them too narrow, the wood panel will be too stiff to flex properly. And too wide will likely let the panel flop around too much.

> In your design it say's 1" rigid fiberglass. Is 1" enough for lows? <

Yes, because the fiberglass is not what's absorbing the sound. The fiberglass just lowers the Q of the trap so it absorbs a wider range, and one-inch 703 is adequate for that.

> could I angle them to achieve the same effect? <

Sure. A couple of degrees ought to do it.

--Ethan
 
If I painted plywood fronts of the bass traps, would this affect the sound in anyway?

Thanks
Tukkis;)
 
What about if you curve the front panel so that it bows out 1-2 inches in the center? Would that negatively affect the panels ability to resonate, or would it just help the diffusion at higher frequencies, or both?

-lee-
 
Lee,

> What about if you curve the front panel <

Your assumption is correct. I'm pretty sure that would reduce the panel's ability to flex properly.

--Ethan
 
Re: Re: Bass Trap Design??

Hi Ethan,

Ethan Winer said:
Tukkis,

> Does the thickness of the plywood determine the frequency? <

Yes, the thickness of the plywood and also the depth of the sealed box.

--Ethan
Click to expand...


How low would a 2x2 3.5" deep panel with 2" 703 absorve if I use 1/8", 1/4", and 1/2" plywood for the front?


Would these pannels absorve at just one frequency or do they have a broad range?

Does the frequency of absortion change if I use different materials for the front...such as MDF?

Thanks,

Luis.
 
Re: Re: Re: Bass Trap Design??

Luis,

> How low would a 2x2 3.5" deep panel with 2" 703 absorve if I use 1/8", 1/4", and 1/2" plywood for the front? <

2x2 is too small to be useful. You go to all that trouble to cut the wood, build the trap, glue it all together - and all you end up with is a tiny absorber that helps only a little. Worse, a panel that small will not be able to vibrate freely.

That said, 1/4 inch plywood gives about 100 Hz., so 1/8th inch is about 200 Hz. and 1/2 inch about 50 Hz. But don't expect any of these traps to do much or work well if only 2x2, especially if you use 1/2 inch plywood.

> Would these pannels absorve at just one frequency or do they have a broad range? <

Neither. They have a medium range.

> Does the frequency of absortion change if I use different materials for the front...such as MDF? <

Yes.

--Ethan
 
John,

> perhaps you should read it also Ethan. <

Interesting. While I can't dispute their findings - those guys surely know more than I do! - I am certain the 2x7.5 foot panel traps I build do not have that double peak in absorption because I've had them measured.

Since you have obviously built panel traps only 2x2 feet, have you found them to absorb sufficiently? It still seems to me that a high percentage of the surface area will not be able to vibrate because it's anchored at the edges. Is this not true?

--Ethan
 
John Sayers said:
Luis - go here and read the BBC research on panel absorbers and you'll see why I recommended 2 x 2 frames. I've also built these absorbers and they work.

http://www.bbc.co.uk/rd/pubs/reports/

perhaps you should read it also Ethan.

cheers
john
Click to expand...


Cool....

Should I put the 1/2" plywood panels on the corners since they absorbe lower frequencies or it doesn't matter?

1/8" and 1/4" more in the center of the wall?

check out this pick.

Luis.
 

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I don't think it matters Luis.

Ethan - We did a whole wall like this in a studio, the main thing was to vary the materials so plywood and masonite were used to vary the mass of the panels.

In luis case he wants a drum room so we are keeping it pretty live and these panels will help attain that.

cheers
john
 
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