Plywood or plaster board?

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Hi all,
About to start my new listening room and have question around wall cladding. One wall is already framed with plaster board on the outside, 2 other walls are brick which I intend to frame over and fill with insulation. The question is should I liner these walls with plywood or plaster board? Plywood can make a very nice warm feeling room but from an acoustic point of view which would be better? Smallish room at around 4.5x5.5 mts, highish contoured ceiling so will need to control bass.

Thoughts please.
 
Hi,

I have been researching this topic myself as im doing something similar.

There are a few video's about sound absorbing framing for US housing using dry walls however this is more about propogating out side of the room using air breaks in the frame structure.

YouTube

For internal sound absorbsion the plaster board vs ply i would suggest that both would be the same or similar as both will reflect the sound. Drapes or curtains would absorb and then there are some really great videos on sound absorbsion wall materials.
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YouTube

Hope this helps
 
Thanks for this. Good watching.

I was really thinking about their properties to work as bass traps / reducers. The theory of a bass trap is that bass pass's through one membrane (dryway) then gets slowed by the insulation then reflects of the other membrane, in my case brick wall then once again slowed by the insulation before passing back through the drywall and into the room.
As I understand it!!!!!

Will ply or plaster board transfer / slow the bass energy best???? That's the million dollar question.

What do you think?
 
My understanding of bass traps is another way of breaking up a reflective surface to mitigate standing waves.

When a preasure wave meets a flat solid surface like plywood or plaster board i assume that most of the energy will be reflected rather than absorbed. This is what is shown in the second video i sent the link for. They did a good control before adding different materials to see the difference in sound / bass absorbsion.

In the 60's there was an experiment with 4mm drilled hardboard which is like a pressed fiber board with a hole every 15mm. This was then studded with 15mm partitions on the rear then mounted to the wall. The idea was that the holes and space behind would act as a reverse helmholtz resonator, trapping bass in a pocket between wall and hardboard. I have not been able to find any supporting scientific evidence for this other than lots of radio studios of the time adopting it.

It also looks awful.
 
That's not really how it works unfortunately, or most rooms wouldn't need anywhere near as much bass trapping inside as they do. (Source, my current listening room is same as you, drywall, insulation, cement basement wall).

In your case it won't matter too much. The bass is going to cut right through the drywall and the insulation won't be thick enough to make a difference really. You'd need to double or triple the thickness. It will reflect off the brick a fair bit but will also carry on through, just not as much because the brick has decent density that will kill the energy.

What's more happening is the energy from the bass starts resonating the drywall, this resonation is damped by the insulation so it does not continue reverberating after the incoming energy has stopped. The bass energy is still reflected into the room and still going to pass through in large quantities.

I guess go with what's cheaper for you that still meets code.
 
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Plywood, all the way. Drywall is one of the worst sounding building materials in common use. I've ruined listening rooms by using it. Plywood isn't perfect, but much better than gypsum board. Brick isn't bad, as long as it's not the only surface.
 
That's not really how it works unfortunately, or most rooms wouldn't need anywhere near as much bass trapping inside as they do. (Source, my current listening room is same as you, drywall, insulation, cement basement wall).


That is exactly how it works, You can read the the latest research on it below:

Noise reduction with coupled prismatic tubes
(PDF) Noise reduction with coupled prismatic tubes /

And no, you don't need as much insulation as suggested, you could review the science, hence my link to an educational site which has plenty of material explaining the physics.
 

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My comment was to what nzlowie said above you, I think you posted while I was typing.

However, You're dealing with helmhotz resonators. Sure, you can design your room that way, I spent a while looking at it and ran simulations. You ended up either needing a lot of insulation, or a decent gap between the insulation and the brick. That's very different from the original poster is talking about doing with traditional wall construction and not tuning a resonator.

If you look at that paper, I didn't read all of it but a fair bit and that's exactly what they're doing as well, tuning helmholtz resonators, but if you look they're doing it all above 1000Hz. Most of the graphs I saw dropped like a rock below that, because again you're dealing with wavelengths tens of feet long, a quarter wave resonator ends up being 11 ft long (25Hz is 45 feet long, 45*.25=11). Sure you can change some of the dimensions of the resonator balancing neck length vs opening size vs volume behind it, but it's the nature of the beast, large wavelengths require large treatments.
 
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Joined 2007
I need help with my shed insulation so very interested in the question, the shed being where speakers will be built and tested.
Doesn't it also depend on the density of the fibre insulation? Rockwool is much heavier that either fibreglass or polyester wall insulation and seems to do a much better job at sound deadening. What snax describes above sounds very much like our Pegboard and that can be covered with an acoustically transparent cloth easily enough if you don't like the look
 
It depends what properties you want.. thick plasterboard stops a lot of sound transmission but you get the reflections. I imagine a material that reflects less would also let more sound transmit through it

You will most likely need additional sound treatment regardless if your choice
 
Acoustic Fields recommends plywood

The sound engineer at Acoustic Fields says that hardwood veneered plywood has a better tone quality than drywall. They also say that the plywood, by virtue of the layering, has better internal dampening than drywall.

I am leaning toward plywood for my home theater/audio room build instead of drywall. Also, I am not concerned so about sound transmission out of the room, so I may opt for thinner plywood to help the bass escape which will help to avoid the creation of room modes compared to more stout wall material (i.e., double 5/8 inch drywall).

Retsel
 
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