Carpet on Low Ceiling?

[diaolosh]

Hey Guys

I've hot a live/recording room 9mx3,5mx2.30 .

No treatment at the moment. Walls are gypsum board and floor is concrete. Due to the low height I was considerig the possibility of covering the ceiling with carpet to reduce early reflections maybe with the extra aid of some cloud panels only on top of the drums.
of course bass traps and panels will be used in the rest of the walls corners.

What do you guys think? Its really not a great option to lower is height by using more panels on the top.

[Gregwor]

Its really not a great option to lower is height by using more panels on the top.

It's a much better option than carpet, that's for sure! If you're trying to improve the sound of overhead microphones, the best thing you can do is add some broad band absorption to the ceiling. Note, carpet is NOT broadband!
Throw some 2x2 panels up there that are made out of 2x6" dimensional lumber, throw 4" of 703 in them and leave that air gap between the drywall and the insulation. Put them in a pattern like this:

Tile Pattern.gif

I read some study that determined this is more effective than an entire ceiling of panels. Strange, but apparently legit.

Yes, you will lose ceiling height, but as long as your mics can go high enough, I'd rather they pick up a decent sound.

If you're THAT concerned about height, tear down the ceiling and build an inside out ceiling. If you're not concerned about isolation with your room, yank the drywall down, stuff insulation in the floor joists and enjoy an awesomely treated ceiling!

You have options

Greg

[diaolosh]

Hey Greg , thanx for your input. This is a concrete basement. The room is a room-in-a-room construction and isolation is of utmost importance as this is a residential area. At the moment i would not consider doing anything to the existing structure.

I am aware that carpet it not a broadband absorver . it was mainly for the purpose of "dampenig" the ceiling a little bit by taking out the early reflections (with the aid of the appropriate wall panels and bass traps). I could lose the extra height above the drumset (plus a small riser) but I would not be very comfortable rehearsing in a 220-2.15 room.

[Gregwor]

I understand. Unfortunately, do to pure physics, the only way to dampen lower frequencies (typically the troublesome ones), you will need depth and dense material. If sound isolation and room size is more important than tonal balance to you, then throw up some thin foam as it will stop high frequency flutter echo type sounds. But know that lower muddy/boomy sounding frequencies will still exist. Or, do as I suggested and lose 5.5" in and have it sound great.

Greg

[diaolosh]

Thanx again, Ill seriously consider your suggestion. The pattern you posted above raises a few questions on whether there will be any resonant frequencies on the blank squares but its intriguing enough to look it up.

[diaolosh]

If I were to

1. Place new 2 inch joists on the existing plasterboard and tuck in rockwool (which i already have) thus treating the entire ceiling with minimum height loss, even if its not the recommended.

2.Do you think a cheap felt carpet , like the ones used in expo booths etc. would be suitable for using as fabric to keep the rockwool tucked in? It happens to have a lot of it in hand. it certainly is not as breathable as other choices. but combined with the absorption will deaden the ceiling.

This may be a stupid suggestion here but id love to know what you think.

[Gregwor]

1. Place new 2 inch joists on the existing plasterboard and tuck in rockwool (which i already have) thus treating the entire ceiling with minimum height loss, even if its not the recommended.

Anything is better than nothing. You know how I feel about it.

2.Do you think a cheap felt carpet , like the ones used in expo booths etc. would be suitable for using as fabric to keep the rockwool tucked in? It happens to have a lot of it in hand. it certainly is not as breathable as other choices. but combined with the absorption will deaden the ceiling.

You can use string or chicken wire or strips of felt. Anything really. Just make your material taught and staple it to the studs. Done. If you want it to look better, you can get some breathable fabric to staple over top of the insulation and then cover the loose ends of it with decorative wood strips.

Greg

[Soundman2020]

Due to the low height I was considerig the possibility of covering the ceiling with carpet to reduce early reflections maybe with the extra aid of some cloud panels only on top of the drums.

Here'sn the problem with carpet: it basically does nothing useful. And the little bit that it DOES so, is the exact opposite of what a small room needs.

Here's the actual test results from a reputable acoustic test lab, when they tested typical carpet in their facility:

carpet-absorption-spectrum-RVBK-S01.jpg

And here's the typical absorption curve that is actually needed in a small room:

Needed-room-cruve-opposite-of-carpet-ENH.jpg

As you can see, carpet does the exact opposite. So instead of making things BETTER in your room, it would make things WORSE!

it was mainly for the purpose of "dampenig" the ceiling a little bit by taking out the early reflections

Carpet will not do that. For a drum kit, most of the energy output is in the range of frequencies where carpet is not effective. Using carpet on the ceiling will only damp the very high end of the spectrum, where drums don't put out much energy anyway. It will make the drums sound "dull" and " lifeless", with no "sparkle" or "sizzle".

I could lose the extra height above the drumset (plus a small riser) but I would not be very comfortable rehearsing in a 220-2.15 room

You don't have a lot of choice! As Greg mentioned, the laws of physics are against you. Personally, I would love to be able to fly by just flapping my arms, and I would not be very comfortable staying on the ground if I flapped my arms....but the laws of physics say that no matter how hard and fast I flap, I'm not going anywhere... So to with your room: if you want it to sound good and allow you to rehearse and track drums, then you HAVE to lose that height. There is no choice. I often repeat this phrase, because it is true, even though many people don't want to believe it: There are no magical acoustic materials. It is that simple. All materials obey the laws of physics, and they are not in your favor here.

2.Do you think a cheap felt carpet , like the ones used in expo booths etc. would be suitable for using as fabric to keep the rockwool tucked in? It happens to have a lot of it in hand.

It might work. You would have to test it, to see what results you get, using REW. Do one test in the empty room, then a second test with the insulation in place, then a third test with the carpet over the insulation. Compare the graphs (mostly the ETC and other time-domain plots) . If it is providing a useful benefit, or just being neutral, then fine, use it! If it produces negative artifacts, then don't use it...


- Stuart -