Is it possible to sound deaden a room too much? - AVS Forum
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post #1 of 17 Old 04-17-2013, 12:00 PM - Thread Starter
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In the first theater room I built, I used canvas fabric frames on all vertical walls. This has really deadened the room, to the point I can easily locate where my speakers are (no matter how much I toe them in). Kind of a big mistake, lol. Think of panels at first reflection, but my full walls are composed of it.

The speakers are usually open and their imaging in a normal room is very good, to where if I close my eyes I have no idea where they're at - not the case anymore.

Is there any equalization that can be done to "fix" this problem? A clap outside my room has a resonating echo, in the room there is nearly no echo. Actually a kind of cool affect as it's very quiet in there, but I'm a little worried I won't be able to fix the imaging issue the room itself has created?

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post #2 of 17 Old 04-17-2013, 12:13 PM
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Not an expert, but sounds like over kill. In the real world, there is always echos. Try breaking the panels up.

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post #3 of 17 Old 04-17-2013, 12:24 PM
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I'm working on my first room as well, but from what I've read, it's quite possible to over dampen a room. Apparently, it happens pretty regularly. Easy enough to fix, though. Just take out some of the panels until you get a sound that you like. There are some metrics for decay times, but you would need to measure the room to know where you're at in relation to them.

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post #4 of 17 Old 04-17-2013, 12:29 PM - Thread Starter
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Easy, but then my room look will get destroyed (lol). Almost all panels are velcrod, so I can take them off, but some of the initial panels I had to nail to the framing because the 1x2s I used weren't perfectly straight (created gaps). Those will be the fun ones to work with.

I will exercise this over the weekend, sigh. I can take most panels off in a matter of seconds, but the ones nailed in..they should stay...it takes me like half a day to create a new panel and get it up on the wall.

so now I'm thinking I'll start with taking all the back panels off first. I hope I can leave all side panels on.

I have like 3 rooms I'm working on that all have projectors, so it's OK I made this horrendous mistake. Mistakes are things you cannot fix!

I wonder in the portions where I remove panels - if I can still use the fabric, and instead of stapling it to the frame - staple it directly to drywall? That way, I still still maintain the canvas look, but it won't have as much of a deadening affect?

You can see pictures of it in my 3D theater room sig link. Floor to ceiling panels.....

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post #5 of 17 Old 04-17-2013, 12:41 PM
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There are lots of theaters on the boards here where people only put absorption at the reflection points, but have fabric panels all over the room. You just leave out the OC703 (or whatever you used) on the panels that you don't want the absorption. For those panels at the back, you might try adding some poly on the face of the absorption (between the fiberglass panel and the fabric) and leaving it there. The poly will reflect the highs, but still retain some of the absorption at the lower frequencies. Depending on how deep the absorption is, this may or may not be of any use. Bass traps need to be pretty thick to work well, and typically they are located in the corners for best performance.

I haven't looked at the acoustic treatments thread in a while, but I think they typically recommend you treat the front and back walls, then treat the first reflection points up to ear height. If you can take the absorption down no the side panels towards the back of the room, that would probably be the best place to start. You might post in the acoustic treatments master thread and see if anyone can offer any advice.

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post #6 of 17 Old 04-17-2013, 12:41 PM
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Quote:
Originally Posted by elmalloc View Post

so now I'm thinking I'll start with taking all the back panels off first.
This is a good start, IMO.
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Originally Posted by elmalloc View Post

I hope I can leave all side panels on.
The side panels are the ones absorbing the reflections that your brain perceives as creating a broad sound source.
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Originally Posted by elmalloc View Post

I wonder in the portions where I remove panels - if I can still use the fabric, and instead of stapling it to the frame - staple it directly to drywall? That way, I still still maintain the canvas look, but it won't have as much of a deadening affect?
You could do that. You might also remove the absorbing material and replace them back on the wall (I'm assuming you filled the frames with OC703 or similar). Or you might, upon some measuring, decide it's worth lining the back of the fabric with some plastic sheeting, and then putting fiberglass back in them and hanging back on the wall - restoring some of the HF reflections, enhancing bass absorption.
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post #7 of 17 Old 04-17-2013, 12:46 PM - Thread Starter
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yes, so I'm sure I did it incorrectly, as I didn't put any absorption material underneath the fabric. I can still fix that too since the panels are removed easily, but that may leave nobody that can help me since probably nobody has empty/hollow 1x2 canvas frames all over their room (probably causing unassuming acoustical issues)? eek.gif

lol.

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post #8 of 17 Old 04-17-2013, 12:53 PM
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You're probably getting diaphragmatic absorption at some small range of frequencies. $200 or so for a measurement rig might be the best money you could spend. Have you looked into that?
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post #9 of 17 Old 04-17-2013, 12:58 PM
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Wow. The room sounds too dead, and you have no fiberglass behind your panels?

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post #10 of 17 Old 04-17-2013, 01:04 PM
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Quote:
Originally Posted by J_P_A View Post

Wow. The room sounds too dead, and you have no fiberglass behind your panels?

Yeah, that's weird. I thought he had fiberglass behind all those panels.
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post #11 of 17 Old 04-17-2013, 01:07 PM - Thread Starter
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I can pay for some diagnostic equiment, that's why I created this thread- haha.

Exactly, what would you have expected it to sound like with no fiberglass behind the panels? I can easily stuff fiberglass behind them if you think that might help?

Honestly I'm not huge into audio, I'm more into video - and I've been using this first room just to figure some stuff out - so I know this is a mistake, just seeing what I can do to get it sounding better (rather than perfect).

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post #12 of 17 Old 04-17-2013, 01:21 PM
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Are you familiar with REW? Omnimic?

I'm not in a position to compare and contrast them and make a confident recommendation. I bought a cross-spectrum labs calibrated ECM-8000 mic (who, for some reason is not taking orders at this time) and Art USB dual-pre (from B&H). Then some monoprice cables (long mic cable, short adapter of some sort for loop back calibration) and a laptop gets you in business with REW. I have about $200 in the setup (not counting laptop, obvs) but haven't really learned to use it - so take that as warning - all my advice is from books and the internet - not experience. A software tone (pink noise in this case, I think) generator and REW's RTA function is what I would start with, in your case.

Some fiberglass panels will likely be an important part of your ultimate solution, but it's tough to say what else without measurements. We can't really take your ears' word for it, you know?
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post #13 of 17 Old 04-17-2013, 01:32 PM
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Fred is dead on that you will need to measure the room before you can make changes that you are sure are improvements. In the mean time, you can pull down the panels that are easily removed and leave the bare wall and see if you like the change or not. Although, with no fiberglass panels, I would have expected the room to sound very much like a bare room anyway. I have no idea what the absorption properties of canvas are, but I would not have expected it to do much.

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post #14 of 17 Old 04-17-2013, 04:01 PM
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Alright guys, just to clear up a few things in the thread -

He doesn't have any absorption behind the fabric. Just fabric everywhere. Now, canvas isn't particularly a good absorber, but it does absorb at a narrow band and when the entire room is covered in it, could certainly still make the room sound 'dead'.

To the OP, can you better describe the fabric you used? Was it actual canvas or something else? If its absorbing too much as is, you'll need to simply remove it, and if possible, use a different fabric that is more acoustically transparent and less absorbent (or more reflective).

Localization is obviously warranted for maybe the front speakers, but the surrounds definitely need to be less localized so they can create a field to 'surround' you. I would start by getting most of the stuff off of the back half of the room and evaluating it then.

If you did want to measure the room, you can do so easily with a microphone and software like REW (it's free). You can check out a video we did on how to install, set up, and run a test with REW here: http://gikacoustics.com/room-eq-wizard-tutorial/

This article is a little technical, but goes into why certain rooms are perceived as "dead" sounding: http://gikacoustics.com/understanding-decay-times/
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post #15 of 17 Old 04-17-2013, 05:35 PM - Thread Starter
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Hi everyone, thanks for the responses.

The back and side walls are floor to ceiling covered with Joanne Fabric's "Duck Cloth Canvas" Fabric. They were assembled by creating 1x2s and stapling the fabric behind the frames, then velcro'd to the wall.

I'd like to still try and use some of the frames if possible, they were difficult to assemble and I felt triumph on completion of them - lol.

Thanks for REW, I've heard of it before when reading about subwoofers/etc. This is good knowledge for me considering this is not my real theater room, and I plan to do an IB array in the real deal - I will need to get all that stuff calibrated.

I also have laminate flooring in this room, it's been stagger studded 15x16 with a solid core door if that makes any difference. I know square is not the best for a theater for many audio reasons, but I have to deal with that.

It is definitely dead sounding where the speaker is very localized, but it's not in any other room; I will read that article and try a few things and get back to everyone. I prefer my front speakers to not be localized and to image correctly (i.e. if you close your eyes, you can't directly place where your speaker is, and it throws a sound stage). There are very specific technical aspects I don't always follow, for example if we do just a simple channel level calibration - I typically run my Epik Conquest subwoofer hotter than calibration, just because I like it like that - I think that's normal with many home theaters though.

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post #16 of 17 Old 04-17-2013, 07:13 PM
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You can use 1 inch cotton batting instead of 1 inch insulation in areas where you want less absorption.

Not sure about your fabric, however. Can you take a close-up pic of it? Can you blow through it easily?

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post #17 of 17 Old 04-17-2013, 08:34 PM - Thread Starter
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I cannot blow through it easily. Blowing does cause it to move a little bit, but I feel no air on the other side.


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