I am in the throws of finishing my basement and have a 16' x 23' x 9+' room set aside for a theater room. The ceilings are high enough to allow either a dropped ceiling or drywall. The rest of the basement is going to have a dropped ceiling, so I can have easy access to things if needed.

After performing a bunch of searches it seems that the preferred ceiling construction is two layers of sheetrock w/ Green Glue between mounted to RSIClips for sound isolation.

My question is this: Is the purpose of drywalling the ceiling for sound isolation from the rest of the house, neighbors, etc, or is there some acoustical benefit over a dropped ceiling? We don’t have any kids, and the wife & I would be watching movies together most of the time, so I don’t care about isolating noise from the rest of the house. Three of the four walls in the room are cement basement walls, so there won’t be any issues with sound bothering the neighbors.

Our preference is to use black 2’ x 2’ dropped ceiling tiles (w/ insulation between the joists) because of the look, plus access to pipes in a bathroom & kitchen above if ever necessary. However, I will go the drywall route if there is a benefit to making the theater experience better.

Good question and I look forward to the experts chiming in. I will be building a theatre within the next couple of months and that's what I was planning to use. The black foram 2x2 tiles in a drop ceiling.

After having to run new cables and panduit across my current ceiling instead of cutting the drywall I swore I would do a drop ceiling next time.

Of course I'm not going to the far lengths of GG and DD anywhere else in the room. Just drywall and insulation to cut the noise a bit.

It doesn't do squat for sound isolation. You might not have kids now, but you could later, or the next owner of your house might appreciate the isolation.

Drywall and a drop cieling both have positives/negatives.

I installed a drop cieling in my theater. Some thoughts about a drop cieling.

Positives:
1) Easy access for wiring and projector upgrades
2) Drop in sound absorbtion panels and specialized panels available for acoustic treatment
3) Easy access for HVAC changes and updates
4) Acoustic tiles seem to dampen sound better than drywall.

Negatives:
1) Vibration/rattling can occur if not properly installed. Rattles/vibration can be mitigated by careful insulation of the cross members.
2) You need to mount equipment to joists or mounting plates above the cieling tiles.

It doesn't do squat for sound isolation. the next owner of your house might appreciate the isolation.

Maybe I'm selfish, but I don't care too much about the next owner. It's not like I can get more for the house if I advertise a drywalled theater room vs. a tiled one.

I have a drop ceiling in my theater, and I helped a friend install a theater that we did drywall.

I prefer the drop ceiling for access. When we upgraded the projector in the drywalled theater, the new projector needed to be mounted further back, so all our cabling and mounting needed to be redone...complete with ceiling repairs.

You can put insulation and other sound dampening materials above the drop ceiling between the joists for isolation. My joists are filled with insulation and I put some sheets of rigid fiberglass panels/ductboard on the joists. The drop ceiling grid is about 2" below that.

I can hear mostly LFE in the living room above the theater, nothing else. The bedrooms on the second floor don't hear anything.

My gallery has pics. A black drop ceiling is the ticket, as far as I'm concerned.

Isolation works two ways. Keeping noise in, and keeping noise out. Keeping noise out means a quieter room, and the volume level can be turned down. And with the volume turned down and a lower noise floor in the room, then your audio gear has a higher dynamic range then. Giving you better performance for free. :D Isolation works two ways. Keeping noise in, and keeping noise out. Keeping noise out means a quieter room, and the volume level can be turned down. And with the volume turned down and a lower noise floor in the room, then your audio gear has a higher dynamic range then.

The biggest drawbacks of a suspended ceiling are no sound isolation and the loss of 2+ inches in ceiling height (needed to install the tiles).

I am glad I did away with my suspended ceiling. It stays it in the other half of the basement, where everything that needs access, is located.

Drywall and a drop cieling both have positives/negatives.

Positives:

4) Acoustic tiles seem to dampen sound better than drywall.


If by dampen you mean sound isolation (lower transmission) - that is incorrect. If by dampen you mean improve in-room accoustics, you are 100% correct. That's basically the trade off, drywall is superior for isolation. Tiles are made of materials that are not unsimilar to accoustic panels, thus are less accousticly reflective and can improve the accoustics of the room. For some of the people on the board isolation is critical, so its drywall, then panels or similar on the walls (and carpet, etc).

In my case, there is an I-beam, some plumbing, and HVAC that I want to be below for an even ceiling across the whole room. I would do that with either a drywall ceiling or suspended. So, I'm only losing a couple inches at the most. However, the walls are poured 10' deep, so I'll still have ~9' ceiling in there, which is plenty high enough for me.

I'll add some insulation between the joists per your recommendations, but it sounds like the tiles are a way better option for my needs. Since they are acoustically active, and I'll have carpet in the room, can I get away will less or no acoustic pannels on the walls?

ISince they are acoustically active, and I'll have carpet in the room, can I get away will less or no acoustic pannels on the walls?

No. The sound from your speakers will bounce off the side walls no matter what you have on the floor or ceiling.

-drin

I'm no sound expert by any means, but my first HT had a drop ceiling and the second had double drywall with green glue. The first didn't isolate bass very well, so you could still hear it upstairs... while the second did a much better job.

However, the first room was very "dead" due to the ceiling... it absorbed quite a bit. The second, not having any acoustic treatments on the walls, had many reflection points. Even though both had reflections off the walls, it was night and day between ceiling types.

No. The sound from your speakers will bounce off the side walls no matter what you have on the floor or ceiling.

-drin

I agree, but it seems like I should at least need less pannels, right? Otherwise, won't there be too much damping?

I agree, but it seems like I should at least need less pannels, right? Otherwise, won't there be too much damping?

The panels on your walls are in place primarily to dampen sound coming from the speakers to the wall to your ears. Think of sound traveling like light in straight lines from the face of the speakers. You'll need the same number of panels on the walls with a dropped ceiling as you would with a drywalled ceiling.

As has been pointed out earlier, you should check with your local city hall to see what the minimum required ceiling height is before you install a drop ceiling. I know a lot of states require a 7 foot finished height from floor to ceiling. If you've got less than that you can run into trouble later on.

-drin

Drin, just a clarification, the ceiling is a first reflection point also (as well as the floor and of course walls). The accoustic gurus debate whether a room should be "live" (more reflective surfaces) or "dead" (less), which depends on the music/movie split (and the room). Based on that, and depending how live the room, the prescence of panels on the ceilings, and carpet on the floor (and seats, how fluff), etc will impact the accoustics of the room.

What is the right balance - heck if I know, but I'd say having panels (and what kind of panels, they sell specialty panels too) instead of hard reflective drywall might impact how much he needs to treat the walls of the room. Ask Bpape or Terry Montlick or Ethan (or others) for answers.

Drin, just a clarification, the ceiling is a first reflection point also (as well as the floor and of course walls). The accoustic gurus debate whether a room should be "live" (more reflective surfaces) or "dead" (less), which depends on the music/movie split (and the room). Based on that, and depending how live the room, the prescence of panels on the ceilings, and carpet on the floor (and seats, how fluff), etc will impact the accoustics of the room.

Thanks Dave. I believe I understand the role of the ceiling in reflecting. My point was that if you consider sound as a vector (much like light - no wave-particle duality discussion, please! :) ), the sound that impacts the ceiling and floor from the speaker surface will be mostly directed towards the back wall or to the opposite surface (in a vector model where the angle of reflection equals the angle of incidence). I don't think a drop ceiling will make enough of a difference that a person can start reducing the number of wall panels in their theater.

My understanding is that the side wall panels are to provide absorption of sound (again using the ray model) emanating from the speakers horizontally or within a certain angle of horizontal - the sound travels from the speaker to the side wall to the back wall, again with the angle of reflection equals angle of incidence. In Chris' first reflection points software you can actually see the results of this ray-tracing as the sound travels from:

front speaker->side wall->back wall
front speaker->ceiling->back wall

This is why the mirror test works. In fact, I just thought of a test using it to show that ceiling reflection points don't impact the walls. Take two mirrors. Put one on the ceiling and find a reflection point. Now put a second mirror on a side wall. Find a reflection point from the speaker->ceiling->side wall->listener location where the sound can actually travel through those points. If you're using a ray model (ie. the sound travels in straight lines, bouncing at incident angle=reflected angle) I bet it can't be done.

I do understand that ceiling and floor treatments, whether they're drop ceilings or carpets, will impact the liveliness of the room. I'm just not sure that it will make enough of an impact that you can decrease the number of wall panels required to cover the first reflection points.

Now, let's see if Dennis, Ethan and Bryan take me to task for saying it. :D


-drin

Thanks Dave. I believe I understand the role of the ceiling in reflecting. My point was that if you consider sound as a vector (much like light - no wave-particle duality discussion, please! :) ), the sound that impacts the ceiling and floor from the speaker surface will be mostly directed towards the back wall or to the opposite surface (in a vector model where the angle of reflection equals the angle of incidence). I don't think a drop ceiling will make enough of a difference that a person can start reducing the number of wall panels in their theater.

You are mistaken. The ceiling and floor certainly have a first reflection point for each speaker the same as the walls, assuming normal rectangular dimensions. It won't be directed towards the back wall unless you have a massive slope in your ceiling towards the back wall that eliminates the first reflection point of the ceiling.

My understanding is that the side wall panels are to provide absorption of sound (again using the ray model) emanating from the speakers horizontally or within a certain angle of horizontal - the sound travels from the speaker to the side wall to the back wall, again with the angle of reflection equals angle of incidence. In Chris' first reflection points software you can actually see the results of this ray-tracing as the sound travels from:

front speaker->side wall->back wall
front speaker->ceiling->back wall

This is why the mirror test works. In fact, I just thought of a test using it to show that ceiling reflection points don't impact the walls. Take two mirrors. Put one on the ceiling and find a reflection point. Now put a second mirror on a side wall. Find a reflection point from the speaker->ceiling->side wall->listener location where the sound can actually travel through those points. If you're using a ray model (ie. the sound travels in straight lines, bouncing at incident angle=reflected angle) I bet it can't be done.

But it is done easily directly off the ceiling, that's the point, it's a first order reflection point.

I do understand that ceiling and floor treatments, whether they're drop ceilings or carpets, will impact the liveliness of the room. I'm just not sure that it will make enough of an impact that you can decrease the number of wall panels required to cover the first reflection points.

Correct. In terms of getting first reflection points, obviously those points on the walls are not going to be affected at all by the ceiling or floor. But since there are also points on the ceiling and floor, those also need to be considered for the exact same reasons the wall points are considered.

It won't be directed towards the back wall unless you have a massive slope in your ceiling towards the back wall that eliminates the first reflection point of the ceiling.

So (again using a ray model) there are no sound vectors that travel out of the speakers at a shallow upward angle, impacting the ceiling at 50% of the distance to the back wall? I find that hard to belive.


But it is done easily directly off the ceiling, that's the point, it's a first order reflection point.

I agree, but the OP asked if having a drop ceiling would reduce the number of required panels on the walls. Since second reflection points don't occur on the walls (with the ceiling as the FRP) there are no fewer FRPs on the walls and the number of required panels should not decrease as a result.

-drin

With my drop ceiling I still have acoustical treatments on the walls.

I think the walls' reflections are more noticeable than floor/ceiling because of the stereo "crosstalk". Abosorption panels made a huge difference in sound quality in my theater.

There's a nice freeware application someone made in the audio theory subforum that shows all the reflection points in a room. It's a nifty tool!

There are plenty of subforums here to feed your OCD. :)

There's a nice freeware application someone made in the audio theory subforum that shows all the reflection points in a room. It's a nifty tool!

It's probably the same one that's in this forum. Do an advanced search on '+first +reflection +points +software' to find it.

-drin

I don't know why you guys are talking like it's either drywall (no absorption) or ceiling tiles (no isolation). I'd say insulate between floor joist, do double-drywall and add acoustic panel to the ceiling or hang some clouds. Facts are: bare ceiling is no good, tiles are like a sieve to LFE, isolation costs money, and you can't cheat physics. If the OP doesn't care about isolation and has lots of headroom, I'd say tiles are fine.

and no, arwun, you can't cheap out on side wall treatments just because you have carpet and ceiling tiles. In fact, side walls are even more important because most speakers are designed for wider horizontal dispersion than vertical dispersion. Don't worry about making it too dead. You would have to go out of your way to get that far (like, cover every sq ft with carpet).

oh.....and run a PVC conduit if you do decide on a drywall ceiling. You never know if you need a new type of cable for whatever projection that comes down the road.

So (again using a ray model) there are no sound vectors that travel out of the speakers at a shallow upward angle, impacting the ceiling at 50% of the distance to the back wall? I find that hard to belive.

That's not what I said. You seemed to be saying that there were not first-order reflection points on the ceiling because it all reflected off the ceiling towards the back wall. That is incorrect. There are first order reflection points off the ceiling if it's a flat ceiling. Obviously everywhere other than that point reflect to other places, like side-walls, front walls, floor, back walls.


I agree, but the OP asked if having a drop ceiling would reduce the number of required panels on the walls. Since second reflection points don't occur on the walls (with the ceiling as the FRP) there are no fewer FRPs on the walls and the number of required panels should not decrease as a result.

-drin

Obviously.

We have just finished installing black acoustic tile. There really is no noticeable sound isolation, but as the HT is directly below the kitchen, it's not a big deal. If it becomes an issue, we can always add some more insulation, and see if that helps. We were in the same boat as you with needing access to pipes, kitchen above, etc, and it has made projector installation a lot easier. I don't know if you have read the following thread:

http://www.avsforum.com/avs-vb/showthread.php?t=722301

If not, before you order black tiles, don't. Just buy the stock white ones and paint them flat black yourself. The Armstrong flat black tiles are not flat black, and as we have discovered offer a very pretty reflection of the screen!

That's not what I said. You seemed to be saying that there were not first-order reflection points on the ceiling because it all reflected off the ceiling towards the back wall. That is incorrect. There are first order reflection points off the ceiling if it's a flat ceiling. Obviously everywhere other than that point reflect to other places, like side-walls, front walls, floor, back walls.


No, I didn't mean to say that. It goes without saying that there are FRPs on the ceiling, just as there are on the walls and the floor. My point was that you can't decrease the number of side wall panels just because the ceiling has been treated, which was what the OP was thinking.


-drin

I read in one thread about someone that did drywall-gg-drywall in the ceiling cavity between the joists before installing a drop-down ceiling. Has anyone actually tried this to help with isolation?

I'm planning a theater in my basement and really don't want drywall because there are so many mechancials in the joists directly above my space, so am trying to figure out the best option to at least help with sound isolation.

Also, I've seen drop down ceiling grids that mount directly to the joists, so you loose very little height from the room which is what I plan to use. Its a bit more of a pain to install from what I read, but at least they can be removed if you need to get into the space above.

I did an all black drop ceiling and I wouldnt do it any other way. Ive already had to go up in it a few times and thank god i didnt do drywall. To me it looks better. Its way more expensive to go with the pure black tiles like I did (not painted) but worth every penny. I added some insulation above in the joists and the sound transfer is negligent if any at all through the ceiling.