Does acoustic foam actually do anything?

[herecomesthemoon]

My room I mix in is pretty well treated. I have GIK Acoustic panels and bass traps etc.

But I have some tiny spots I think could do something with and the panels and even smaller panels won't fit.

Would foam actually do anything to help these areas?

Maybe a better question does foam actually do anything in general?

[Hugh Robjohns]

Foam panels are perfectly effective within their design limits:

https://www.soundonsound.com/reviews/choosing-using-porous-absorbers

... so if you need more absorption then foam is a valid option, but do you really need more HF absorption in the room?

Normal foam panels only absorb high-mids and highs, and the thinner the foam the higher the effective absorption cut-off frequency.

So it's very easy to end up with far too much absorption of the mid and high frequencies in a room, with relatively little low-mid and LF absorption, resulting in a boxy-sounding and unbalanced acoustic environment.

[herecomesthemoon]

Hi Hugh

Yeah, I get what ya mean. My room is fairy good. It still has a sound it's not 100 percent dead. Which I wouldn't want. So might end up just leaving it.

I always see these two views of foam does nothing, and foam does something.

I will have a good read of the link you sent. Thank you

[CS70]

Maybe a better question does foam actually do anything in general?

They do absorb high frequencies, which have very short wavelengths.
But in the average room "studio" you usually want absorption on a much broader band.

[innerchord]

But I have some tiny spots I think could do something with and the panels and even smaller panels won't fit.

Is this actually 'tiny spots' of bare wall? If so, you're worrying about the wrong thing. You don't need all of your surfaces covered.

[Sam Spoons]

I have four untreated areas on the ceiling and four on the walls, I intend to add additional panels in those areas but none of them are 'tiny spots'.

How about a pic of your room, that might give us a better idea whether treating those spots is likely to give you the improvement you are looking for.....

[herecomesthemoon]

I have four untreated areas on the ceiling and four on the walls, I intend to add additional panels in those areas but none of them are 'tiny spots'.

How about a pic of your room, that might give us a better idea whether treating those spots is likely to give you the improvement you are looking for.....

Ceiling wise I have for some spots there. How much is ceiling treated?

I must get a pic up.

[Sam Spoons]

This should give you an idea. There are other untreated areas just out of shot but it works well, as is, for mixing/listening and is ok if I stay around the mixing position in front of the desk when recording acoustic instruments

[innerchord]

This should give you an idea.

I spot "racetracks"! I don't recognise the model, though. I presume you monitor at low levels or use a limiter with those?

[Sam Spoons]

This should give you an idea.

I spot "racetracks"! I don't recognise the model, though. I presume you monitor at low levels or use a limiter with those?

Sorry, 'racetracks'? I don't understand...

[Hugh Robjohns]

The passive bass radiators in your monitor speakers.

[Sam Spoons]

Ah, never heard that before but I get it now..... I guess we're talking NASCAR rather than IoM TT

innerchord, they are Kef 104aBs from the '70s, no limiter but around 75dB at the mix position usually. Tweeters are the issue, thankfully the tweeter fuses protects them well enough for the odd occasion when I do something silly (feedback usually).

[DanDan]

Good foam is just as effective as fibre. But it is usually sold in very small amounts, and often is half of what it appears to be. 4" Pyramids are not the same as 4" solid.
It is good for killing flutter or very early reflections at very short range, e.g. in a booth. The pyramid angles help. The depth can be increased by any amount by adding fibre behind.

[innerchord]

innerchord, they are Kef 104aBs from the '70s, no limiter but around 75dB at the mix position usually. Tweeters are the issue, thankfully the tweeter fuses protects them well enough for the odd occasion when I do something silly (feedback usually).

Thanks. Do you love the depth of image as much as I do? I wonder why I've not seen 104aB with that configuration? All the others (including mine) have the tweeter at the top. Are yours rare?
Sorry for the diversion; I just had to know!

[Sam Spoons]

They are home built from a KefKit 104aB, the baffle for the bass driver and tweeter comes with the kit, the baffle for ABR (which is, basically, a B139 without a magnet or voice coil) does not. The upshot is that you can rotate the active drivers for vertical or horizontal orientation, and in my case upside down to get the tweeters at around head hight when seated.

In fact the active drivers in mine are non standard as the originals were no longer made when one of mine failed. Wilmslow Audio had sourced uprated drivers with better power handling but compatible Thiel-Small parameters. My ears are not good enough to say if they sound any different but they are pretty good, I like them a lot (and a pair of Wilmslow Audio LS3 kit built Rogers L3/5A copies), I've had them for 40 years so pretty attached to them.

[Guest]

I recently bought some acoustic foam from Acoustic Foam Direct (UK) and it's been very effective. As long as you understand the limitations of the material and don't expect it to do something like outright soundproof your room, I think it's a worthwhile buy.

[The Bunk]

I've just had my "home studio" redecorated and that involved removing all the foam panels from the walls / ceiling (and yes, they make a huge difference without needing to cover the entire room).
Trouble is that, in removing the panels, most of them took half the wall with them due to the adhesive. They've been up a good 10 years I would say. I'm actually a little wary of replacing them and just use cans for monitoring, unless anyone can suggest a slightly less troublesome way of applying / sticking them to the walls.
Fortunately the decorator did a great job in covering up / making good.

[Drew Stephenson]

Glue a couple of old CDs to the back of the foam, pop a couple of small tacks in the wall, hook foam onto tacks.

Or build a whole, mobile wooden frame that's massively over-engineered and makes your room look like the space station. Not necessarily recommended...

[Martin Walker]

Or build a whole, mobile wooden frame that's massively over-engineered and makes your room look like the space station. Not necessarily recommended...

Ground control to Major Drew

[MOF]

Trouble is that, in removing the panels, most of them took half the wall with them due to the adhesive. They've been up a good 10 years I would say. I'm actually a little wary of replacing them and just use cans for monitoring, unless anyone can suggest a slightly less troublesome way of applying / sticking them to the walls.

I stuck my tiles, 1m x 1m, to very thin wood panels (slightly smaller than the tiles so that you don’t see them) which I then cut two slots in at the top, which line up with the two pin type of picture hooks on the wall. A bit fiddly hanging the panels but I’ve not had any fall off.

[The Bunk]

Excellent tips, thanks chaps!

[DC-Choppah]

I sent my room diagram to Auralex. They do some analysis and send back a custom plan.

They had me placing absorbers and diffusers around, and bass traps in the corners in a specific layout.

Only some of the wall and ceiling are covered up. Much of the room is untreated still. I even have a big window.

Then you can run through Mike Senior's swept tones and see how the room has become more flat vs frequency. Sounds less like a small room when recording. Doesn't have that small room sound any more. Just neutral.