View Full Version : Acoustic treatment for a room


David Pakman
August 12th, 2018, 02:41 PM
I'm building out a small studio in a room that is about 11 feet by 11 feet, with a roughly 7'8" ceiling and wooden floors. It is all drywall and currently very echoey. I know the echo will go down once I have the equipment in the room, but I do want to deaden it as much as possible. Because it will be filmed as well as recorded, I can't build a small booth or do things that will create a small room within the room.

The simplest solution seems to be to buy acoustic foam paneling and cover the walls and ceiling with it. My questions are:

1. If I want it as dead as possible, do I just cover the full walls and ceiling with acoustic foam, or are there reasons to only cover PART of the walls/ceiling, or not the ceiling at all, etc.

2. I know that the "specs" on 1" and 2" foam describe different frequencies that the thicker foam cuts, but in thinking about making the room as dead as possible, do I just want to go with the 2" foam over 1", or are there reasons to do 1"?

3. Last time I used acoustic foam, I got a spray on adhesive that claims not to damage paint, but it badly damaged the paint when I removed the foam. Is there now an actual adhesive that won't damage the paint?

Oren Arieli
August 12th, 2018, 02:51 PM
There are quite a few DIY soundproofing videos on YouTube, and I suggest you start there. As for my own experience controlling the reverb in a very 'lively' room, the acoustic foam (even the expensive treated variety), is not very effective. With sound waves, you need to convert and disperse their energy in order to reduce them, that is done best with thicker/denser material, like rockwool. In addition, the angles of the walls play a big role in the level of echo and reverb. You can't change that much without building a room within a room, but large diffusion panels filled with rockwool worked nicely on my own build. Adding a cork floor, and/or thick carpet will also help. Beyond that, it's going to be very difficult to get rid of that last 20% that will give you a reasonably 'dead' room.

David Pakman
August 12th, 2018, 02:53 PM
That makes sense, I'm going to check out some videos. Am I understand correctly that if I put down a thick carpet and cover the walls and ceiling with acoustic foam, it might get me 80% of the way there? I'm wondering if maybe that with a good voice processor could be a good enough solution.

Andrew Smith
August 12th, 2018, 04:58 PM
If you're doing this for voice work then it's always worth looking at a portabooth.

Andrew

Jim Michael
August 12th, 2018, 08:54 PM
Acoustic Panels | Bass Traps | Sound Diffusers | GIK Acoustics (http://www.gikacoustics.com/)

Very reasonable and better than foam.

Rick Reineke
August 13th, 2018, 09:30 AM
Partial or wall-to-wall carpeting would may a huge difference to start. Then add panels and/or maybe bass traps if needed. Window drapes and plush furniture help as well.

David Peterson
August 13th, 2018, 07:51 PM
Sound blankets are the usual approach to treat a room on set during a shoot. But if you've got a permanent set up then this general approach is still a good cheap way to go about it, but you can do it more permanently.

vlog #42: sound blankets again, & an overview of audio with a RED Scarlet Weapon - YouTube

vlog #41: my birthday!! & using "sound blankets" - YouTube

vBlog #4: My multimillion dollar "surprise" ADR recording studio! - YouTube

Oren Arieli
August 13th, 2018, 08:20 PM
That makes sense, I'm going to check out some videos. Am I understand correctly that if I put down a thick carpet and cover the walls and ceiling with acoustic foam, it might get me 80% of the way there? I'm wondering if maybe that with a good voice processor could be a good enough solution.

I can't give you a number, since there are way too many variables we haven't discussed. I'm not an audio engineer, but I can pretty much promise you that you won't get 80% reduction of echo through foam and carpet alone. It will likely sound better than what you have, but that is because you're dispersing the reverbations (but not absorbing them well enough).

Tom Roper
August 18th, 2018, 01:03 AM
Architectural fiberglass, it's rigid, it's dense, it's cheap and available in 1 in, 2 in 3 in thickness. You can use a hot glue gun to cover it in a beautiful fabric of your choice. I didn't make this up, the recommendation came from Audio Magazine in the 1980's, had a series of articles on constructing a LEDE (live end/dead end) sound room. I had very different preconceived notions back then about how a sound room should look and act. The article arrived and was timely, completely redesigned my media room in accordance with the recommendations, which included bass traps. It became a beautiful and exquisitely sounding audio/video media room before its time. Don't blow it off, they knew some things back then. Architectural fiberglass is your best construction material. Covered it looks great, is economical, and sound wave absorbent. Use 3 inch on the back wall behind the speakers, 1 inch on the side walls. The opposite end is hard surface. Live end, dead end. It strikes just the right balance, not muffled and not echo-y. The speakers were placed in the dead end. To stand back there was eerie, so quiet.

Another feature was from the genius of Bob Carver, inventor of Phase Linear, Sunfire, Carver. He's still around. Google him. Anyway, he had a gimmick called Sonic Holography, only it was no gimmick. It was true sonic hologram based on the principal sound cancellation from constructive/destructive interference, exactly as done with lasers and smoke for visual holography.To create the illusion, and it was a very convincing illusion btw, required careful positioning of speakers and treated surfaces. The greatest compliment I received again and again from my amazed friends, was the question repeated, "Where are the other speakers?" Sounds actually floated in space, the imaging was phenomenal. It was put to extraordinarily good effect in no small part by the architectural fiberglass panels which were very cost effective.

Brian Drysdale
August 18th, 2018, 01:19 AM
If on a budget, the papier mache egg crates on the walls do a good job. It helps if you don't have a square room, we used an attic room for this and the slopping ceiling reduced the standing waves. It was good enough to fool a BBC sound engineer with the recordings.