Sound (Sort of) Proofing Help Needed

scubalab

Looking for some help in reducing sound 'leaking' from our theater through a wall into a guest bedroom.

I realize there are things that I could (should) have done better when this was constructed over the years, but for now, I just need some advice on my best options to at least reduce the sound without tearing into finished work!

A little background...

The front of our theater is a combination of a built in cabinet, subwoofers, and a traditional wall. The top 4 feet is a traditional wall. I did add insulation to the wall, but did not stagger the studs, so it helps just a little. The bottom 3.5 feet is two built in sealed subs on either side of a 5' wide nook or cabinet. On the other side of this wall/cabinet/subs is a the guest bedroom. Where the cabinet and subs protrude into the bedroom, I built a counter and mounted cabinets above for storage.

From the bedroom, I have access to the back of my equipment via a removable 3/4" sheet of plywood (3'x5'). As you can imagine, this 'leaks' a lot of sound into the bedroom.

I'd like to add some sound proofing or deadening material to the inside of the cabinet (on the plywood 'access door' and possibly the top). I can also add material to the walls behind (and above) the subs. I was thinking foam (egg crate) style studio panels, but understand these don't do much to reduce the sound rather than help eliminate sound reflection. Is there something (fairly thin - 2" or less) that I can line the back and top to help REDUCE the amount of sound leaking into the bedroom?

My niece lives in the room now and is a senior at PSU. She 'says' the sound doesn't bother her (she uses NC headphones), but I'd like to do what I can to minimize the sound in her room while watching TV/movies.

Tips/advice welcome. I realize I can't totally eliminate it, but wondering what might be the best (easy and fairly cost effective) thing I can do without reconstructing. What material would work best?

Thanks in advance!

VR3

Build a wall in front of it. Leave a gap between them, just empty space. R15 insulation both walls, two layers 5/8 drywall with the green goo between the layers, rock N roll

scubalab

Trey, you devil. Yeah... That would do the trick, unfortunately I have neither the room to build another wall, nor do I want to start another big project. What's funny, is there USED to be a wall there with a door, but we needed to knock it down to gain a little space in the guest room...

Just looking for something to line the back of the cabinet that will do the best at absorbing (some of) the sound going through the back cover. Kinda like the stuff you're using for the anti-diffraction rings? But, before I buy something to stick on in there, I'm hoping someone can say what material might work better. It's mainly sound coming through the 3/4" plywood access panel. I already sealed the gap with weatherproofing tape, just looking for the best material to line the inside of the panel to lower the sound levels a tad!

Not a huge deal, just trying to improve a bit.

Here's an OLD drawing of the plan view (some minor things changed with seating in the theater, but still mostly accurate to what I built):



Here's a cross-section view of the wall between the theater and the guest room. The area between the "go zone" and the "no go zone" is where I need to put sound reducing treatment (on the Go Zone side).



Here's a picture of the back access panel and counter on top of the rack and subs taken from the guest room. The wooden bump-outs on the counter are the backs of 'cubbies' I built for the front L/R speakers. (More on those later.)



And here's what I did to deaden the sound from the speaker boxes. I framed outside of them, lined with poly-fill and 3/4" Styrofoam insulation boards and drywalled over that. That helped a lot.

BlueMDPicker

Hey Al!

Sound curtain hung from hooks?

VR3

Absorption is key, a big curtain you pull could help?

scubalab

Hello Mike! Hope you're well. As for a curtain, it's somewhat possible... I do not want to hide the cabinets and counter we just built from view in the guest room. We are planning to put up a curtain to the left side of the cabinets to cover a nook (18" wide from floor to counter, 38" wide from the counter to the ceiling) under the stairs, but that will only partially block the sound. Imagine an inverted "L" shaped curtain to the left of the cabinet covering this space:



I can hear the most sound coming into the room through the plywood panel under the counter. I was hoping to put something that wouldn't be too noticeable on the inside of the audio rack built in that would absorb the sound that 'leaks' into the bedroom. I was thinking something like this:

https://smile.amazon.com/BUBOS-Acoustic-Treatment-Decoration-Insulation/dp/B08BC16WK4/ref=sxin_9_ac_d_pm?ac_md=2-0-VW5kZXIgJDUw-ac_d_pm&crid=I9L0AAO02UXU&cv_ct_cx=sound+proofing+padding+for+wall&dchild=1&keywords=sound+proofing+padding+for+wall&pd_rd_i=B088QYXDHM&pd_rd_r=b00508cc-b004-4418-a45e-05b3c6a03c94&pd_rd_w=Wkjfe&pd_rd_wg=bcogq&pf_rd_p=1996aa5c-bfb7-40b7-b677-a9bfb33f2c53&pf_rd_r=J8BT6FZ6J5V65C3G2ZJN&qid=1617048580&sprefix=sound+proofing+,aps,178&sr=1-1-22d05c05-1231-4126-b7c4-3e7a9c0027d0&th=1

Here's a picture of the inside of the audio rack (I know... time to dust!). I would like to put black sound absorbing material on the back panel (behind the equipment) and possibly the top inside of the built-in. Don't think the sides would need it? There's really only that 3/4" plywood access panel separating the back of all the equipment from the guest bedroom.

pitdogg2

drill some holes fill the void with LOTS expanding foam.....

scubalab

pitdogg2 wrote: »

drill some holes fill the void with LOTS expanding foam.....

There are no voids... The separation from the back of the equipment rack and the bedroom is JUST a piece of 3/4" plywood as an access panel...

I suppose I could put expanding foam around the subs, LOL, but then I'll never get 'em out if I needed to!!

BlueMDPicker

Too bad the upper cabinets and counter are there. A good murphy bed would help attenuate the subs I bet.
Edit: is there such a thing as a murphy couch? Like the jump seat on an airliner.

scubalab

Yeah... things certainly could have been done differently to better sound proof between rooms, but unfortunately since our house is on a slab (no basement for storage), space for storage is at a premium. We needed the cabinets because we lost a closet there, and turned another walk-in closet in the old into a simple closet and kitchenette. But, at the same time, we gained a nice little studio apartment that our niece is using while at college and will eventually be rented for some fun money since we're so close to a big university!

We DO plan to put a small couch (like an Ikea sectional that converts to a double bed) in that space after my niece moves out and takes her desk that's there now. It'll be up against the back of the audio cabinet and I imagine that will also help.

So, since I can't build anything different, I just want to do what little I can to at least reduce the sound leaking through a bit. I know it won't be perfect, but given these options, what do you all think would work better? Something like this (high density polyester fiber):



Or this (foam studio panels):



Or do you think I'd be better off just getting a piece of sound insulating fabric and hang it like a curtain JUST INSIDE the back of the audio cabinet?

Of those three (or some other material to put inside the back of the cabinet) what do you think would give me the best results (understanding that none will equal building another soundproofed wall!)?

scubalab

Here's the FINISHED counter in the guest room. The big (5'x3') access panel behind the desk opens up to the back of my audio rack in the theater.