Rehearsal room needs to be made soundproof

[Johannes]

As you can see, there is an old house, which is extended by a new house.
Both have a basement, with separate walls, but on ground level, there is only one wall between old house and extension.
The floor touches that wall (see drawing).

My problem is that Room A, B and C are sleeping-rooms.
Room A and B are my children's rooms, and Room C is my parents' room.
There is a little noise coming to any of those rooms through the walls.
It's not much (like a TV in the next room, or someone talking in front of the door), but it keeps you in those rooms from sleeping.

The noise is certainly not coming through the hallway, and stairways.

Some details about the Durisol bricks:
These bricks are "composed of specially graded raw wood shavings and chips, which are neutralized and mineralized, then bonded together with Portland cement".
These bricks are hollow, and are filled with concrete.
Imagine cement-blocks, made of minarlized wood chips.
http://www.durisol.com
http://www.durisol.at (german)

The floors and ceilings are made of reinforced concrete.

My band plays Death Metal (but we rehearse at very low volume, especially for that style ) with drums, 2 guitars (no stacks, just 1x12 cabinets) bass and a singer.

We can only rehearse in the evening.

Here's the questions:
How can I minimize the noise in Rooms A, B and C?
Is it best to do something about the ceiling of the rehearsal room? There's not much room to work with (only about 10cm)...
Or should I do something about the walls?
Only the wall with the door is finished with plaster, the other walls are untreated.
Oh, and the solution should be cheap...

Please help!

[knightfly]

Johannes, I really like these EASY ones... (Kidding, holy cow am I EVER kidding...)

First, I'm assuming that the top part of your drawing is the only floor plan, and that the rest is an elevation, meaning that rooms A and B are on the second floor, the garage and room C are on the first floor, the rehearsal space is in the basement and the green, wavy line is ground level. If I've somehow mis-construed, post back and correct me.

Second, I'm not going to lie to you and tell you how you can fix this for the price of a good meal, if at all - it looks like you're the victim of the dreaded "flanking noise", which is NEVER easy or very cheap to fix.

I file away (in my head) catchy little phrases all the time, to be later re-gurgitated as I see fit - the one that comes to mind here is "Good, Fast, Cheap - pick any TWO - you can NEVER have all THREE..."

Sorry for the negativity, but I don't want you to get your hopes up too high and then not be able to help you. If I first dash ALL your hopes on the rocks, and then manage to help you a LITTLE, I'm a HERO. If, however, I only help a little bit in the FIRST place, I'm just AVERAGE. And, I REALLY like being a hero... :=)

OK, (finally) all seriousness - I work 12-hour shifts at my job as an Industrial Instrumentation and Control Tech - when my night shifts are slow (things not going to hell nearly as quickly) my time is my own, and that's when I answer about 40% of the posts. I've just copied your entire post to my laptop and will, as soon as possible, analyze your construction more deeply.

At first glance, this looks like a tough one - possibly not AS tough, til you threw that word "cheap" into the pot... Right now, on the surface it looks like you may be getting structure-borne noise travelling up through all that concrete, transferring to the concrete floors, then into the walls which are radiating the sound into the rooms. Some way or another, the path needs to be broken with non sound-conducting material - the problem is this "cheap" thing.

I'll have to look at your drawing a lot more and consider costs of various "fixes", and that may take a while. I won't, however, give up until I've run out of ideas. This is because I'm generally pretty stubborn - notice how the first three letters of "stubborn" and "stupid" are the same? There's a really good reason for that... :=)

Check back in a day or two, sooner if you'd like.

Oh, and if you could, please check and see WHAT part of the sound is the MOST prevalent in the ABC rooms (probably will be bass and kick drums, but not always)

Working on it... Steve

[Johannes]

Thank you knightfly, for your efforts.

You are right about my drawings, on top is the floor plan and below the elevation.

Concerning Priorities:
Cheap is less important than good.

I'll check back what part of the music transfers the most into the other rooms. Last time I played a CD really loud and went up to room A. When everything else was quiet I could clearly recognise the songs standing close to any wall, but I think the higher frequencies are not that much of a problem.
As I said before, the noise is not that loud, but it can keep you from sleeping.
If I can somehow reduce the level of the noise entering the structure by 6-10 dB that might already be sufficient, but who knows.
And my primary question is which part of the rehearsal room picks up the most noise, ceiling or walls?

Thank you again for your help!

[knightfly]

Johannes, I just spent about 1-1/2 HOURS composing an answer for you, only to have it EATEN by the gods of "Not Funny" - Sorry, but it will take a while to even remember everything I said. Give me a while to cool my irritation and re-post... Steve

[knightfly]

Johannes, I’ve marked up part of your drawing to show the flanking paths in your building - the sound waves, as shown by the arrows, cause the various walls and floors/ceilings to vibrate. This vibration is transmitted through the concrete and other masonry, at approximately 10 times the speed that sound travels in air ( the blue lines) - each intersection of your building (circled in red) appears to be hard-coupled, so there is nothing to attenuate the sound’s travel through the masonry except distance.

Each of these surfaces, since they are vibrating from the sound energy being passed through them, will also radiate sound out into their respective rooms. Any dissimilar materials used as floor or wall coverings will have a reducing effect, but not a lot unless there is a resilient layer to decouple them.

In order to stop this sound radiation from happening, you need to keep the masonry from being excited as much as possible. This needs to be done at the first possible stage after the sound is generated, and before the masonry ever gets a chance to vibrate.

It’s hard to say for sure which component of your building is causing the most problems, but I would think it’s probably the ceiling over your studio. It has the largest area so would probably be most likely to resonate the most. One way to find out if this is true is to use a sound level meter in rooms A, B, and C with a CD cranked up to live levels in the studio - first do this with no vehicle in the garage, (I’m assuming from the drawing that the garage is directly above the studio???) - Then, put a vehicle in the garage and close the door again, and re-check levels in the ABC rooms with NO OTHER CHANGES. If the ceiling is the major culprit, you should get measurably lower sound level readings in the ABC rooms with a vehicle parked in the garage, because the weight of the vehicle should lower the resonance of the concrete and decrease the transmission through it.

One more relatively inexpensive test would be to put your drums and bass amp (guitar amps too, probably) on floated panels such as 19mm plywood or MDF resting on foam mattress pads (the egg crate foam kind) and see if sound levels outside the room are reduced.

Beyond that, you would need to use some of the narrow, 41 mm 25 gauge steel studs and “furr out”your walls and ceiling, adding two layers of 16mm gypsum wallboard to every surface except the floor. If you decide to go this route, I’ll help you with details . They can get pretty interesting when you’re doing it to a ceiling of concrete.

If these changes don’t kill enough of the sound, you would need to do the same in the affected rooms. I doubt, however, that you’ll need to go that far in order to get the reduction you’re looking for.

You would be a lot better off if each intersection of the construction wasn’t so well-coupled to the next, but changing that AFTER construction would be a MAJOR pain in the butt.

As I understand it, there is not a big market for Resilient Channel in Europe, mostly due to the use of more steel stud construction which has an inherent flexibility - this flexibility is a fair substitute for the decoupling properties of Resilient Channel. That’s too bad, because it may be difficult to find a relatively thin way to de-couple additional ceiling wallboard from your concrete ceiling.

If you can find out, possibly from some construction people in your area, what materials are available there for sound control, it would make things easier for finding a solution to your ceiling… Steve

[Johannes]

Thank you so far Steve!
Again you are right with all your assumptions, everything is hard-coupled.
The building was definatly not built with that in mind. I know because my fahter and I built it....
And you are right, the garage is directly above the rehearsal room, but it has no door, just the big opening so I can drive into it.
I'll make the test with and without car in the garage (good idea!) and post the results afterwards.

You confirmed some of my thoughts about the problem, after a lot of reading I also think that the ceiling takes up the most of the noise.

We also plan to build a riser for the drums as you describe it, and we'll put the amps o some damping pads.

What exactly does "furr out" mean? Does that refer to something like this:

looking down:

////| . . . ||
////| . . . ||
////| .--+||
////| . . . ||
////| . . . ||
////| .--+||
////| . . . ||
////| . . . ||

////|........wall

--+..........studs

||............plasterboard

. . . glasswool, rockwool (isolation)
(The plasterboard should be straight of course...)

In German this is called "Vorsatzschale", it's like a drywall where only one side is covered with plasterboard. It is built in front of the other wall and not connected to the other wall, only to the floor and ceiling.

I would rather not build somehing into the other rooms, and decoupling the existing ceiling is as you say "a MAJOR pain in the butt.", or as I would say impossible.
If that was my only option, I'd make my rehearsal room somewhere else, because a new constructed barn-like building might be cheaper and easier to do....

[knightfly]

"a new constructed barn-like building might be cheaper and easier to do.... " -

Good possibility - not to mention getting enough head-room to play standing up :=)

However, if you were desperate there are always ways of getting around a problem - for example, there are the powder-operated concrete nail guns - some of them have a narrow enough snout that you could take light (and NARROW) steel drywall studs, use an electronics chassis punch, punch holes in one side large enough for the nose of the nail gun, and shoot the studs onto the ceiling - then, add rockwool insulation between, screw on two layers of wallboard (well caulked) and voila - 10 dB (roughly)

If you have the option, though, I'd seriously consider the separate building approach. I've been living with the other way for about 20 years, and I'm finally going to (hopefully) get a separate building in the next couple of years (about ll meters x 18.25 meters with 4.88 meter minimum ceiling height) (you never know when you might want to take a break from recording and play some basketball :=)

Let me know what you find on the tests, or anything else... Steve

[khallgren]

Just a comment here--

Those concrete shooters aren't really that big of a pain to use--if you use wood studs you can just attach them directly to the concrete. Put some glue on the stud (I've used Liquid Nailz brand but I'm sure there are dozens of others), shoot it into the concrete on both ends and in the middle and wait for the glue to dry before attaching some resilient channel and drywall.

The guns are approx. $60 here in the US, then you buy the shells and the nails. Be sure to use ear protection if you're going to be doing more than a couple of shots--those things are freakin loud.

BANG!

Kraig

[knightfly]

Good call, Kraig - the only thing I'd disagree with is fastener distances. If you're going to hang RC at 12" or 16" centers on a ceiling, followed by two layers of 5/8" sheet rock, you would want more than three places supported on a flat-laid 2x4. Support strength is mainly due to VERTICAL depth of framing, and 1.5" isn't much of a depth.

If you went that way, I'd recommend a concrete nail within 2" of EACH RC strip.

The other reason I was hesitant about even mentioning RC, is that apparently Europe uses very little wood framing and as a result there is not a plentiful supply of RC available there. From what I hear, they use more steel stud construction which (in normal construction) is almost as good as using RC on wood studs, hence the lack of sources for RC.

That's why I mentioned using narrow steel studs, with holes punched thru one side - it's difficult to get ANY kind of tool or fastener into the inner channel of a narrow stud at an angle, and even if you could, the angle would weaken the support given by the fastener head... Steve

[Johannes]

Thank you Steve for your help so far.
I have been very busy in my daytime job, so I had not much time for investigating the problem, but yesterday I finally managed to check out some things:

I listened to the noises with and without car in the garage. There was no remarkable difference.

We consider rehearsing with phones, so our drummer bought a cheap set of e-drums, so we tried these (e-drums, and real cymbals).
This sort of reduced the noise very much, but you can still hear his bassdrum hits. No cymbals, no other drums, just the 'thud' of the bassdrum.
So it seems that mainly lower freqencis get through.
The other e-drums are in comparison much lower than the e-bassdrum when listening inside the rehearsal.

[knightfly]

Johannes, good to hear from you again - I'm not sure I understand what you're doing with the E-drums - if you're listening through headphones, why is there any sound in the room at all? I would have thought that you'd be doing an entirely electronic mix, and not even having speakers on in the room. Am I missing something here?

I'd still vote for the separate building, any chance of that happening in the near future?

If not, you should check around at commercial insulation companies to see if Resilient Channel is even available in your area - if it is, maybe you could put a layer of 16mm drywall on channel in the affected rooms, caulked around the edges (no firm contact with other surfaces) - the thing is, this would need to be done in all the affected rooms, so would get kind of expensive. Also, if the noise is coming also from the floors, it might not solve the problem.

The separate building is definitely the best approach from my view, if you can swing the expense... Steve

[Johannes]

Like you I would prefer relocating the rehearsal room into an extra building. But this can't be accomplished within at least one year, so we have to work with what we've got.
This is why we decided to use e-drums instead of normal drums. E-drums is what these things are called over here in Austria.
E-drums are trigger pads. Our drummer bought a real cheap set of old tama hexagonal pads including an Aleses DM-5 drum sound mudule (It would have been cheap for the DM-5 alone...).
So he's still beating but pads instead of drums. And he still uses his hihat and cymbals. But the hihat and cymbals don't get through the walls. The bass pad is still quite loud though. We might try another bass-pad.
We guitarists have preamps and can go directly to the mixer, so we are able to rehearse with headphones.
I know this is not perfect, and we will relocate as soon as possible.
Thanks for the help so far...