Sound proofing a common wall

[bodia]

Just curious if any of you that live in a townhouse, condo or apartment have ever tried to do any sound proofing on the common wall(s) with your neighbors? I'm not talking about "sound proof" dry wall, or sheeting and a second drywall application, or anything like that. Something less costly that has the desired effect. Maybe cost isn't the issue, but something a little easier to do. Thoughts?

 

[gush]

I think that is going to be a very difficult task my friend. This will be interesting.

 

[sergiodeblanc]

The only thing cheaper and as effective as drywall is the air space between double walls.

 

[László]

It can't be done without a double wall, a double ceiling, a double floor, airspace, insulation, and possibly isolation pads between the wallboard and studs. The reason is that as sound waves vibrate the floor, ceiling and walls of a building, these surfaces actually act like the head of a giant kick drum, especially re: the low frequencies.

Thus, even if you could effectively put in enough material to absorb the higher frequencies (very difficult to do in the first place), the lower frequencies with their longer wavelengths will penetrate even bass traps and beat against that wall.

Another problem occurs if there is any ducting or plumbing that goes through more than one apartment, condo, etc. These will transmit sound very nicely.

This is why recording studios use "room within a room" construction, why they mount their floors on rubber supports, and why they use special heating, ventilation and cooling equipment.

That said, you can do a few things to reduce the annoying transmission of sound, though their effectiveness compared to soundproofing is very slight:

1. You can put something like an amp or loudspeakers on isolation platforms, like Auralex Grammas. While this will do nothing for the neighbors adjacent to you, it will reduce the vibrations coming through your floor and through the structure of the building itself, thus becoming less annoying.

2. Use mass to your advantage. If you can cover an entire wall with book cases, and you have enough books, the mass will prevent some of the sound waves from turning your common wall into that giant kick drum.

3. Use very thick carpeting and thick carpet pads. This will help a little bit. Not much, but every little thing you can do is good.

Foam will not do it. Expensive bass trapping will not do it.

The only thing that will do it is complete isolation, specialized materials, and a very nice landlord (if you live in a rented space as opposed to a condo).

 

[Blues Trucker]

So Les, How thick of a dummy wall do you think is required? Would furing strips and Styrofoam be adequate? Or would you need to go 2x4 construction with R19 or better? How about the floor. Is a slab floor good for sound Isolation?

 

[bodia]

Great, you guys are a ray of sunshine! What am I gonna do with the 600 egg cartons I've got saved up?!?

Ok seriously, thanks for the feedback. It's about what I expected. Perhaps I should have said sound dampening instead of sound proofing. I'm in a three level townhouse in an end unit. I share one wall with a neighbor. That wall is staircases to the upstairs and basement, and two bathrooms, as well as the utility room in the basement. I'd like to do something to quell the minimal bleed I get from the neighbors, as well as something that will minimize the stuff coming from my side so I can turn it up a little more.

Any options other than what's already been offered? One thing I might consider is additional insulation. Although patching that many holes doesn't sound like fun.

 

[László]

So Les, How thick of a dummy wall do you think is required? Would furing strips and Styrofoam be adequate? Or would you need to go 2x4 construction with R19 or better? How about the floor. Is a slab floor good for sound Isolation?

You need two things: Airspace, and mass. Styrofoam doesn't have mass, and it will transmit vibrations, since it doesn't resist sound wave pressure like air (think something akin to hydraulic pressure here).

So 2x4 construction is the preferred method, ideally with special rubber isolation pads between the 2 x 4 and the sheetrock. Several companies make these, and the most well known is probably ASC.

A studio I consult for (and have booked for major session work) has their floors between the recording room and mix room not only separated with double wall construction, but the concrete floors of each room float on rubber mounts AND there is a rubber separation between the concrete of each room to isolate the floors. The ceilings work in the same way. There are special doors, there's special HVAC, and the walls are sound absorbers and bass traps. It's basically a perfect place to record that sounds great.

Of course, this studio was designed by a famous studio designer, Russ Berger, and cost a cool million bucks to build out back in 1992 (and that's without the equipment that was installed), so you can imagine the cost today. But if you want soundproofing, this is the real deal.

The point is that you can reduce sound transmission more cheaply, but true soundproofing and room design is an acoustic art and a science, and it ain't cheap. The problem is that either a room is soundproof, or it doesn't work at all. There's no such thing as "a little bit pregnant." If sound gets through, it's not soundproof.

Pick your poison.

 

[Dusty Chalk]

Everything Les said is correct, but bodia did later qualify that anything he can do to attenuate would be a good thing, for both parties.

So probably the most important thing you can take away from what Les said is the mass part of the equation. They actually do make lead lining for soundproofing applications.

The unfortunate side effect of this is, sound doesn't travel in straight lines -- it travels more like a combination of water and electrical current -- path of least resistance/flow like water, taking every available avenue of transmission. So if you just hang a lead sheet on the wall, and do nothing along the edges or corners, you've wasted your money. You might get a little bit of attenuation, but nowhere near what you'd expect.

So let's go back to the original question -- you want to be able to crank it, but for what? Recording? Then get something like a Rivera Silent Sister -- which is sort of a vocal booth for guitar amps. You don't want to get a Silent Sister, then get an actual isolation booth for guitar amps -- they do make them. How do you think the big guys mic guitar amps right behind the drum risers?

They actually do make full room size isolation booths. They're not cheap, but they're so not cheap, you can rent them, so rent them and decide if that's what you want to do before you invest in them.

They don't breath -- they're designed not to. As Les pointed out, breathing leads to sound leakage leads to defeat. So they're not the sort of place you'd want to rehearse. When I was setting up a home studio in a previous residence (a spare basement room in a group house I rented a room in), I was going to go through a lot of trouble with the ductwork -- I had designed a way of completely closing it off with piece that locked into place, and redirected the air elsewhere so that there was no air pressure trying to open it back up.

Want to rehearse? Rent a rehearsal space. Seriously. They're not that expensive.

Want to jam? I don't have a solution for you. Especially this forum that tells you, "gotta keep your main volume dimed" -- yeah sorry I can't -- I live in an apartment -- I've got neighbors on 2 or 3 sides, depending on ... well whether or not one of the neighbors is home or not (they rarely are). This is definitely one of those situations where something like a Kemperer through a pair of studio monitors that you actually can turn down is the best solution. I have just compromised on my sound -- when I'm just practicing, I don't need the best tone I can accomplish, which is probably for the best -- I concentrate on improving my finger skills, where 90% of the tone is anyway.

 

[The Fight]

I just buy a blender for my new tenants.
The ninja is a very good blender...

 

[vchizzle]

I lived in a similar condo set up for a long time. The best spot for you to setup is likely the basement(assuming it's concrete floors), at least you're not vibrating the sub floor and floor joists. One of those gramma iso pads to put the amp on might help too. I had very limited space so I couldn't do much. I used a Port City 1x12 there which is a decent cab for lower volume playing since the cab design throws all sound forward. I don't think my neighbors cared much either. I didn't play at home as much since my rehearsal space with the band let me be LOUD.

 

[László]

I have very understanding neighbors, but there are times that I simply find it necessary to use the Mesa Cab Clone and record with that. Then I use the "impulse speaker response" trick to put a little polish on the track.

 

[The Fight]

I sound proofed one of my kitchen walls bcs that's where the neighbors wall was. I simply cut out cardboard and clued that to the wall, then I bought sound foam off Craigs list and glued that on the cardboard. Then I bought some long, thick curtains to hide the bomb shelter look in my kitchen. Last I hung up a picture. I also use a 2x12 cabs that I raised off the ground and set it on shock absorption foam to delete some bass response that might travel through the hard wood floors. Also plugged up the back of the speaker cab with loads of foam and towels, to prevent the bass traveling up the walls.
It's also awsome to have two master volume controls, that really helps out.

Iv communicated with my neighbors, so i have a good idea when loud is too loud.
Iv never got a noise complaint.
Good luck man, I hope that helps out.

 

[László]

I sound proofed one of my kitchen walls bcs that's where the neighbors wall was. I simply cut out cardboard and clued that to the wall, then I bought sound foam off Craigs list and glued that on the cardboard. Then I bought some long, thick curtains to hide the bomb shelter look in my kitchen. Last I hung up a picture. I also use a 2x12 cabs that I raised off the ground and set it on shock absorption foam to delete some bass response that might travel through the hard wood floors. Also plugged up the back of the speaker cab with loads of foam and towels, to prevent the bass traveling up the walls.
It's also awsome to have two master volume controls, that really helps out.

Iv communicated with my neighbors, so i have a good idea when loud is too loud.
Iv never got a noise complaint.
Good luck man, I hope that helps out.

Wit respect, you didn't soundproof the wall. Soundproofing means that no sound whatsoever is transmitted to your neighbors, regardless of your volume. As you know, that isn't what's happening in your situation.

But people use the term loosely, even though it really has a very rigid meaning.

What you did was add a little mass and absorption of higher frequencies, and deaden the sound a little bit. That's not a bad thing, in fact, it has helped in your situation. In fact, it was a very nice thing to do!

But...soundproofing it ain't.

 

[Jazzedout]

I think it is very difficult task to soundproof an already built house/apartment etc.
I believe that is one of the reasons the amp modelers are very successful.

I could not see me cranking an amp in the house with a 2 year old kid, even if I do not have a problem with neighbors.
I only do it when the kid is not at home, but then again I prefer cranking it up with a band or jamming friends.
For practicing/noodling an AxeFx/Kemper/Eleven Rack setup is fine through headphones, or my studio monitors. On top of that is very easy to decently record as well.
My 2p and all that...

 

[The Fight]

Wit respect, you didn't soundproof the wall. Soundproofing means that no sound whatsoever is transmitted to your neighbors, regardless of your volume. As you know, that isn't what's happening in your situation.

But people use the term loosely, even though it really has a very rigid meaning.

What you did was add a little mass and absorption of higher frequencies, and deaden the sound a little bit. That's not a bad thing, in fact, it has helped in your situation. In fact, it was a very nice thing to do!

But...soundproofing it ain't.

Yeah your right, in my situation sound proofed would be head phones. But I guess it's a bit impossible for an old apartment like mine. I have given my self some peace of mind, knowing that I can turn it up to desired volume. An mby that is the point, when I think about it.
Sound proofing is some serious science, and it's an expansive one, or when imimplemented correctly.

 

[Blues Trucker]

Want to thank Les. hes been real helpful and put out great info. Ive learned a lot from this thread.