How should I treat this ceiling?

[brentcn]

Hello, first time poster here -- going to try to lay this out as best I can, and hit all the benchmarks! I'm a drummer, and sometimes a recording engineer. So in the middle of all this craziness, we moved! The basement in the new place has been completely finished, and it's all mine to use a practice/teaching/recording studio! The builder did a very nice job finishing the basement, with the drop ceiling and recessed lighting, but of course this is all terrible for sound. The room is almost empty, and there's a pretty harsh reverb right now, with some flutter. The ceilings are 7 feet tall, and the usable space is diagrammed below.

The ceiling in the photo is a "drop" ceiling, with a metal lattice and square "tiles". As it is, the ceiling is very flat and reflective, and my goal is to treat the ceiling so that the room feels "bigger", if that's possible. I plan to make drum set recordings occasionally. I'm not too worried about volume; the neighbors aren't too close, and loud volume will only happen occasionally. Mostly I'll play a muffled practice kit (pictured).

On hand, I have about 12 pieces of 2' by 4' Owens Corning 703 insulation. I could use this to make absorptive ceiling "tiles", that could replace the existing tiles.

For the walls, I already have several insulation panels, plus two curved diffusor panels, and two corner bass traps. On the floor, I will have one large rug under the recording kit, and another large rug elsewhere.

Three questions:

1. With all this in mind, how would you recommend that I treat the ceiling?

2. Should I get bass taps for the other corners of the room? I don't plan on mixing or mastering very much; the room will be a live room, for drum recording and, occasionally, group rehearsals.

3. If you were setting up a drum kit to record in this room, where would you place it and why? Along one of the shorter walls? Or along one of the longer walls.

[Paulus87]

You already have the framework in place for a very well treated ceiling - just replace all of those reflective ceiling tiles with "acoustic ceiling tiles" which are basically just semi rigid insulation in a colour of your choosing. Fill the void above the ceiling tiles with lightweight fibreglass insulation, 8" or more would be good. You shouldn't need any other treatment on the ceiling in terms of absorption, effectively the whole ceiling will be a large broadband trap, potentially absorbing down into the lows quite well depending on how much space is behind the tiles.

Placing bass traps in the corners is always a good idea, and spreading the other panels you have out evenly across all the walls will lower the overall reverberation in the room quite significantly.

Where to place the drum kit is completely subjective. If you wanted to take this further you could make certain parts of the room more live than others, using reflectors or diffusers, or perhaps variable acoustic devices. But simply doing all of the above will probably improve your room to the point where you will be quite satisfied.

Paul

[brentcn]

You already have the framework in place for a very well treated ceiling - just replace all of those reflective ceiling tiles with "acoustic ceiling tiles" which are basically just semi rigid insulation in a colour of your choosing. Fill the void above the ceiling tiles with lightweight fibreglass insulation, 8" or more would be good. You shouldn't need any other treatment on the ceiling in terms of absorption, effectively the whole ceiling will be a large broadband trap, potentially absorbing down into the lows quite well depending on how much space is behind the tiles.

Placing bass traps in the corners is always a good idea, and spreading the other panels you have out evenly across all the walls will lower the overall reverberation in the room quite significantly.

Where to place the drum kit is completely subjective. If you wanted to take this further you could make certain parts of the room more live than others, using reflectors or diffusers, or perhaps variable acoustic devices. But simply doing all of the above will probably improve your room to the point where you will be quite satisfied.

Paul

Thank you very much! I have some follow up questions if you don't mind.

Is there an acoustic ceiling tile you would recommend? The existing tiles are somewhat soft to the touch, but they're only about a half inch thick. I'm not sure if they qualify as "acoustic tiles". Do you mean the tiles that are 1 inch or 2 inches thick?

There is a lot of space between the tiles and the floor joists -- about 16 inches -- so there is plenty of room to add insulation above the tiles.

What variety of insulation would you recommend, going above the tiles? And why 8 inches thick? Would I get similar results if I used 2 inches of OC 703 above each tile?

Do you think the added insulation on top of the tiles will help to reduce the flutter echo? Or is that mostly due to the flat walls and floor?

[Paulus87]

You already have the framework in place for a very well treated ceiling - just replace all of those reflective ceiling tiles with "acoustic ceiling tiles" which are basically just semi rigid insulation in a colour of your choosing. Fill the void above the ceiling tiles with lightweight fibreglass insulation, 8" or more would be good. You shouldn't need any other treatment on the ceiling in terms of absorption, effectively the whole ceiling will be a large broadband trap, potentially absorbing down into the lows quite well depending on how much space is behind the tiles.

Placing bass traps in the corners is always a good idea, and spreading the other panels you have out evenly across all the walls will lower the overall reverberation in the room quite significantly.

Where to place the drum kit is completely subjective. If you wanted to take this further you could make certain parts of the room more live than others, using reflectors or diffusers, or perhaps variable acoustic devices. But simply doing all of the above will probably improve your room to the point where you will be quite satisfied.

Paul

Thank you very much! I have some follow up questions if you don't mind.

Is there an acoustic ceiling tile you would recommend? The existing tiles are somewhat soft to the touch, but they're only about a half inch thick. I'm not sure if they qualify as "acoustic tiles". Do you mean the tiles that are 1 inch or 2 inches thick?

There is a lot of space between the tiles and the floor joists -- about 16 inches -- so there is plenty of room to add insulation above the tiles.

What variety of insulation would you recommend, going above the tiles? And why 8 inches thick? Would I get similar results if I used 2 inches of OC 703 above each tile?

Do you think the added insulation on top of the tiles will help to reduce the flutter echo? Or is that mostly due to the flat walls and floor?

If the tiles are made from a semi-rigid insulation similar to OC703 or 705 and they do not have a hard reflective coating then no need to change them.

The use of lightweight fibreglass (or similar) above the tiles is to further improve the absorption qualities of the drop ceiling - 8" is a minimum recommendation for effective absorption down to around 100hz. If you have 16" of room then do a full fill of lightweight fibreglass (if you can afford it) that'll be good down to ~50hz. Even if you only fill 8" with another 8" of air behind it then you'll still have effective absorption down to around 50hz but with less efficiency than a full fill. For the money, the last option is probably the best compromise - you can always add more if you are not satisfied.

The variety of insulation I would use is just the cheapest, lowest density (lowest gas flow resistivity) thickest stuff you can find. Typically pink or yellow fluffy attic insulation is the cheapest and is perfect for the job. If you can afford it then you can use polyester non itch loft insulation but it is quite a bit more expensive, at least it is here in the uk.

If the tiles do not have a hard reflective facing then there shouldn't be any flutter echo between the floor and ceiling. If you are noticing a flutter echo then it will probably be between two parallel walls. If you are noticing it between the ceiling and the floor then I would say your ceiling tiles must be reflective, in which case exchanging them for the porous soft faced type would be best.

Using 2" of OC703 above each tile is not going to gain you much of anything at all compared with a full fill of low density fluffy. I would use the OC703 for more wall panels or as a backing to corner traps. The lower the frequency range you want to absorb the thicker and lower density insulation you need. 2" of any dense insulation is not going to be thick enough for effective absorption below 500hz.

Paul

[DanDan]

If the tiles feel soft to the touch they are probably acoustically absorbent. Can you identify them? Or some close photos, particular edge on.
Ideally one would fill the void with light fluffy, but if these tiles are soft they might sag. Let's get clear on what they are first.

703 is ideal acoustically, but you would need a cosmetic facing.

As one treats a space bit by bit, some very vivid anomalies reveal themselves. Flutter can be treated by absorbing and or redirecting. Ply panels angled.
I would go for a chequerboard approach. Live areas of wall facing absorbent. Hitsville studio is well worth looking at. Angled areas of wall.

[brentcn]

If the tiles are made from a semi-rigid insulation similar to OC703 or 705 and they do not have a hard reflective coating then no need to change them.

The use of lightweight fibreglass (or similar) above the tiles is to further improve the absorption qualities of the drop ceiling - 8" is a minimum recommendation for effective absorption down to around 100hz. If you have 16" of room then do a full fill of lightweight fibreglass (if you can afford it) that'll be good down to ~50hz. Even if you only fill 8" with another 8" of air behind it then you'll still have effective absorption down to around 50hz but with less efficiency than a full fill. For the money, the last option is probably the best compromise - you can always add more if you are not satisfied.

The variety of insulation I would use is just the cheapest, lowest density (lowest gas flow resistivity) thickest stuff you can find. Typically pink or yellow fluffy attic insulation is the cheapest and is perfect for the job. If you can afford it then you can use polyester non itch loft insulation but it is quite a bit more expensive, at least it is here in the uk.

If the tiles do not have a hard reflective facing then there shouldn't be any flutter echo between the floor and ceiling. If you are noticing a flutter echo then it will probably be between two parallel walls. If you are noticing it between the ceiling and the floor then I would say your ceiling tiles must be reflective, in which case exchanging them for the porous soft faced type would be best.

Using 2" of OC703 above each tile is not going to gain you much of anything at all compared with a full fill of low density fluffy. I would use the OC703 for more wall panels or as a backing to corner traps. The lower the frequency range you want to absorb the thicker and lower density insulation you need. 2" of any dense insulation is not going to be thick enough for effective absorption below 500hz.

Paul

Thanks again! Probably I'll go with the 8" of insulation.

If the tiles feel soft to the touch they are probably acoustically absorbent. Can you identify them? Or some close photos, particular edge on.
Ideally one would fill the void with light fluffy, but if these tiles are soft they might sag. Let's get clear on what they are first.

703 is ideal acoustically, but you would need a cosmetic facing.

As one treats a space bit by bit, some very vivid anomalies reveal themselves. Flutter can be treated by absorbing and or redirecting. Ply panels angled.
I would go for a chequerboard approach. Live areas of wall facing absorbent. Hitsville studio is well worth looking at. Angled areas of wall.

Looking at the backside of the tile, it's a fibrous type of thing. The front face is a thin, cement-like white paint. They seem strong enough to hold the insulation.

You mention "chequerboard" -- I was thinking that I would stagger absorption panels on one wall, and then stagger panels, in an opposing way, on the opposite wall. In between the panels, I might hang some diffuser panels like these:
https://vicoustic.com/product/wavewood- ... rown%20Oak

What do you think?

EDIT: Funny you mention Hitsville -- the day I moved in, I met Ed Wulfram on the street, welcoming me into the neighborhood. Small world!

[DanDan]

Not looking good for those tiles. Can you blow through the cement side?

[brentcn]

Not looking good for those tiles. Can you blow through the cement side?

Nope, the coating is too thick. So maybe blowing insulation up there isn't a good idea after all?

[DanDan]

Too much unknown. But for sure installing fully absorbent tiles, would be the single most effective treatment you can do.
Even with no filling in the void a standard suspended ceiling, 16" void, 1" tile, is good down to 50Hz.

[Paulus87]

Too much unknown. But for sure installing fully absorbent tiles, would be the single most effective treatment you can do.
Even with no filling in the void a standard suspended ceiling, 16" void, 1" tile, is good down to 50Hz.

Really Dan? Down to 50? I am surprised. 16" is less than 10% wavelength of 50hz. I am not doubting your knowledge but would be interested to see data for this claim if it exists? Even if it does go down that low I would expect the absorption to have huge notch filters rather than smooth efficient absorption all the way down that low.

Paul

[brentcn]

Too much unknown. But for sure installing fully absorbent tiles, would be the single most effective treatment you can do.
Even with no filling in the void a standard suspended ceiling, 16" void, 1" tile, is good down to 50Hz.

Good to know, thanks. Time to go shopping for some ceiling tile.

Given the layout of the room, do you have any advice for positioning of absorbers and diffusers on the walls? Large, homemade bass traps will go in the corners of course. I'm thinking that, since the walls are long, and parallel, I'll need lots of both. But I want the room to still be lively, as much as is practical. Splaying out the walls is something I'd rather avoid.

What do you think of these things?

https://www.ebay.com/sch/i.html?_from=R ... r&_sacat=0

[brentcn]

Too much unknown. But for sure installing fully absorbent tiles, would be the single most effective treatment you can do.
Even with no filling in the void a standard suspended ceiling, 16" void, 1" tile, is good down to 50Hz.

Really Dan? Down to 50? I am surprised. 16" is less than 10% wavelength of 50hz. I am not doubting your knowledge but would be interested to see data for this claim if it exists? Even if it does go down that low I would expect the absorption to have huge notch filters rather than smooth efficient absorption all the way down that low.

Paul

Well, I can get 2" thick tiles, most likely. Hopefully that will sufficiently absorb low end: 2" tiles plus 14" of air gap. OTOH, I could also rip out the drop ceiling and start hanging 703 panels everywhere, but that's probably overkill for a local drummer recording the occasional demo. When I do get called for sessions, there are two very nice studios within 10 miles of me.