Acoustic room treatment

My kit is out of the main lounge now, in it's own mini dedicated room. Not long ago I downsized the size of my gear in anticipation of this. One benefit is to gain higher sound quality for slightly less outlay on my part-ex, as I no longer needed to fill such a large space. The other benefit, for the first time ever I could add room treatments without worrying about the aesthetics too much. End result should be some great sounds in the pipeline. Plus a pretty mad looking audio room / padded cell.

I have recently ordered a load of acoustic grey foam for the walls. It's 45mm thick, so not too intrusive. It's similar to the pyramid section profile, except more like multiple blades per panel. The idea is to arrange every other panel so the blades alternate between horizontal and vertical. I will have enough to cover virtually all the wall area, but wondered if that might be too much? I've been advised this panel is ideal for absorbing most horrible room reflections / echo's etc.

I also have a pair of 3 foot high corner foam bass traps for behind each speaker. I could order more, so they go floor to ceiling?

Finally the wooden floor will be covered in carpet or heavy wall to wall rugs.

There is a danger I could go too far and the room may sound too dead. I want a balance between control and retaining some airiness. I'd appreciate any tips before I get the glue out! Should I leave half the room bare painted walls? Maybe order some other products? Help appreciated....

 

My tip is to tell us what it sounds like.

Regards
Steve

 

Hi,

From the sounds of it, you are going to end up with room that is too dead. You will find it interesting for a few hours and then it will slowly send you around the bend (go into a acoustics lab enechoic chamber and you will see what I mean).

Personally, I don't like the profiled face absorber products as it is basically a marketing tool. Absorbers don't need to have any strange profiled faces (diffusers do) as it is essentially the thickness, type and spacing from the mounting surface that defines their absortpion characteristics. What tends to happen, is that the sharp foam edges degrade and break off over time. They are also quite expensive too really.

I think a bit of reading up on the issues relating to sound absorption and diffusion would be a good idea.

If you are serious about this, I recommend ordering a copy of this book of amazon. We sometimes have to lecture to audio engineering students on this topic and I always recommend they read this book as a good summary.

http://www.amazon.co.uk/exec/obidos...8-1/ref=sr_8_xs_ap_i1_xgl/026-7279656-7258049

There is also free stuff off the net, some of it very in-depth. Here's a good place to start:

http://www.rpginc.com/research/index.htm
http://www.rpginc.com/research/TechBullDiffCritList.pdf

http://www.rpginc.com/news/library.htm (look at document called "Minimizing acoustic absorption in project studios")


What's the room dimensions?

 

it's definitely will be too dead.

first think is to treat first reflection points (FRP) on side walls.

then carefully play with FRPS on the floor, ceiling, back wall, front wall.

other than that is to go for diffusers.

bass traps usually are essential.
i did fiberglass traps in the corners which did very significant improvements.

commercial products are scary expensive.
you can try to DIY by imitating them.

http://www.customaudiodesigns.co.uk/products.htm

 

Talking of bass traps and room modes, check out this funky animation that visualizes room modes in terms of particle displacement and pressure:

http://www.isvr.soton.ac.uk/SPCG/Tutorial/Tutorial/Tutorial_files/Web-standing-rooms.htm

 

All the stuff so far only came to £120 from ebay. I'm sure I'll just have a large panel on each side wall and see how it sounds. I think they look like some form of modern art in a way.

I'll have that much spare I may end up selling some off via the classifieds on here in a month or so for £50.

Btw, I'm not serious at all. Just messing about and experimenting that's all. Anything should be an improvement on my totally bare room at present.

 

Experimenting with the foam is the easiest way, just don't use too much and trust your ears.

I think you will find some very big differences in sound by varying the location of the foam, on the side walls in particular.

 

Use the 'mirror method'.

Imagine the foam pieces are mirrors on the wall and place the foam where you could see the speakers (tweeters) from your listening position.

 

I just put a thick wodge of foam behind my speakers and the bass has stopped bloom on certain low notes. Foam was not acoustic, but from an old chair, measuring 100mm x 500 x 500. Certainly an improvement so far - reccommended.

 

Thanks for the advice so far, including Tenson's input via pm

I will get a mirror out now to plan the initial areas of attack.

 

Post some photos when finished perhaps?

 

The foams have arrived. Due to the shape of each panel (flat one side and grooved on the other side) I have the option of stacking them up. I have the following options:

1. Single layer with grooves showing (depth min 11mm max 45mm)

2. Double layer with flat front showing (depth 60mm everywhere, as grooves mesh together hidden inside)

3. Triple layer with grooves showing (depth 70mm min 100mm max)

I am inclinded to go triple depth for each wall panel at mirror point, as it doesn't look particuarly intrusive and I have plenty of tiles. What do the experts think?...

 

Actually I'd go single layer with the eggbox-side facing out, at all the reflection points: left side, right side, behind, ceiling, and even in between the stereo front, since I think that's the type of foam you have. On the floor reflection I'd put a rug. At least, that's what I'm happy with, though I'm no expert.

 

I have a rug in place at the moment. I can't put the foam in between my speakers at it would cover my plasma up! I have plenty to cover all mirror points in triple layer, if that would be better?

 

YEP.
Maybe this should have been realized before buying anything..
But do proceed, it's an interesting reading...

 

Thanks, I'll try it in stages.

To the nay sayers; these are such good quality product at such a bargain price I am glad I picked these up. I've saved hundreds over equivalent items. Besides I'd rather experiment and listen to music right now, rather than spend months reading white papers.

 

Hi.

What is the specification of the foam? Got a link?

How big is the room, and what's the layout?

How big was the room you left?

 

I don't doubt there are some differences

However the price differential is quite exceptional, so I suspect it is another example of diminishing returns. If have have to use a little more product to obtain a similar absobtion, then so be it. I must say though, that these foams seem near identical to one's I already have from Studio Spares and other samples from other specialist acoustic companies. No doubt those in the know could measure some difference.

I am cynical enough to believe most of these products cost pennies each from China, then somewhere along the line attract £300 per box audiophile / pro price tag's. Even the old chair foam I originally tried made some positive difference afterall.