Reducing HVAC Noise in Theater Rooms

[admin]

HVAC noise is usually the #1 problem in home theater rooms. Minimizing the source of the noise is one of many steps in the pursuit of a state of the art theater room. These external noise influences have deleterious masking effect on the audio reproduction much like light pollution does with display devices.
A simple tweak such as replacing the bi-fold doors that contain your HVAC air handler with an acoustically treated solid core door is about the easiest and more noticeable sonic upgrade you can make to your system. This in turn can extend listening sessions at reduced SPL levels which lessens the susceptibility of listening fatigue.

Discuss "Reducing HVAC Noise in Theater Rooms " here. Read the article.

 

[MDS]

I have a similar problem with my AC and my proposed solution is similar to the article. I haven't actually done the project yet so I don't know if it will be successful but I sure hope it improves things.

The air handler is behind a wall next to the door leading to the garage and there is no door for access to it (except from the rear in the garage). If you open the return air vents on the bottom of the wall and look inside you see that the air handler is basically enclosed in a rectangular space that is 3 feet wide by 3 feet deep by 9 feet tall (ceiling height). The air handler sits about 3 feet off the ground. So basically I have this large cavernous space where the return air is sucked in at a very high velocity and that apparently imparts sound to the surrounding drywall.

When I first moved in, I measured the sound at 70 dBC near the return air vents. When that AC/Heat kicks on, you have to turn up the volume by about 10 dB! This was the only real 'negative' I considered before buying the house.

My first attempt (hack?) is to apply sound dampening sheets to the floor, side, and back walls of the enclosure to minimize vibration and transmission of sound through the walls as well as to line the floor with the studio wedgies like was done in the article. If this $150 'solution' will reduce the noise by 10 dB I'll be a happy camper.

 

[Jack Hammer]

HVAC noise can definately be distracting and annoying. I was able to fix the sucking noise that came from my air intake. Not as nice as the fix in the article, but along similar lines. It's 6 months later and I still can't hear it at all.
For those who have a problem, I can't impress upon you enough how much of a difference fixing it made for me. I really don't believe I lived with it for so long when the fix wasn't that complicated to do and made such a difference. For those who helped me, you are still appreciated immensely.

Jack

Link to thread

 

[Alex2507]

At work I saw the owner of the HVAC company walking out with a bag full of 24x48x1 duct sound insulating panels. I asked about them and he ended up handing them over with some great advice. I was told that lining the inside of the air return duct would give me the biggest improvement. My return is 7" to the filter. Insulating the inside of that 7" duct using spray contact cement adhesive was a huge improvement.

I went on to remove the blower and insulate the box that encases the blower. I noticed that my blower had an oil hole to put like 17 drops of 30 weight non detergent motor oil into every two years or so. I even put weather stripping on the backside of the grill. I then went on to insulate the living room difuser box and weather strip that grill. I raised my air handler to insert isolation pads and used acoustical caulk all the way around the bottom of it.

Insulating that 7" of return duct made the biggest improvement just like I was told. Before that we would automatically reach for the remote as soon as the AC kicked in to turn up the volume. After we would still reach for the remote like a couple of Pavlovian dogs but we're over it now. I gave my dishwasher motor the same treatment.

The insulation is black and you should spray exposed cut edges with contact cement to seal in the fiber glass. If you have pilot lights anywhere nearby you should turn them off before spraying contact cement near them. I was told that you could get this insulation at an HVAC supplier.

 

[SWHouston]

Alex2507,

Just wondered, given your background, if you had ever installed, or seen the type Sheetrock, found at:
www.quietsolution.com

They seem to be one of the sponsors here, just thought I'd ask.

Have a good Day !

 

[Alex2507]

Alex2507,

Just wondered, given your background, if you had ever installed, or seen the type Sheetrock, found at:
www.quietsolution.com

They seem to be one of the sponsors here, just thought I'd ask.

Have a good Day !

Nope. Never even heard of that one. I have heard of the USG version of it though. I actually called them about availability and price. At the time it was unavailable in New England and like 10 times more expensive than regular drywall. They claimed that it was 8 times more sound proof than regular board. I could be wrong about the numbers but that's the general impression I walked away with.

Bottom line for me is that I can always afford $100 for a little drywall project but a grand is a little tougher. I'm also thinking that the price might come down by the time I'm ready to start.

Alex

 

[SWHouston]

Alex2507,

Looks like this product is about ten times the cost too. Saw where their 1/2" board was $40, each I think!

It's been a while since I did any floating and taping, but as I remember, a 4x8 sheet was WAY less than that !

Have a good Day !

 

[Alex2507]

Alex2507,

Looks like this product is about ten times the cost too. Saw where their 1/2" board was $40, each I think!

It's been a while since I did any floating and taping, but as I remember, a 4x8 sheet was WAY less than that !

Have a good Day !

I'm assuming that's an 8' sheet and I think the Depot sells them for $8-$10 so that's 4 or 5 times more than regular.

 

[SWHouston]

Alex2507.

Not that I personally need that stuff, but, I'd sure like to see it.

They have sheets that are about 1 1/2" thick, I bet you'd have to have at least four guys to hold it, and one or more to screw it in place, if you wanted to use some of that on the ceiling, I definitely wouldn't trust nails !

I can just imagine the look on someone's face, when the finale of the 1812 Overture, was more than loud Cannon Shots !

Will be looking around to see any samples of it.

Have a good Day !