Rehearsal room on concrete floor with crawl space

[Rain]

Hi!
After two years of exploring other options (which would always get too expensive in the end) I'm making plans for turning my garage into a rehearsal room. I would like to use my acoustic drums there if that's possible. Ofcourse I needed to have the loudest drums that were ever made (slightly exagerated but not by much: top of the line 80's Pearl kit with big size power toms, deep brass snare, 22" and 24" bd's) and I accept that it probably won't be acceptable to use these at home in the evening or night time. The drums will easily reach 110 Db. I also have a nice Roland e-kit that I'm happy to play. Next to drums, I play guitar and piano but I can play those without amps over headphones. The loudest will probably me singing or the thumps and twacks on the rubber edrum pads. The purpose of the room will be to make me able to practise without disturbing my family and neighbours. I think that will be doable with a room within a room in my (single brick wall leaf) garage. Now my question:

Since there's a (non-accessible and non-vented) crawl space underneath my garage, which will probably act as a big resonant chamber, do you think it's possible to get reasonable levels of sound isolation to play acoustic drums in my garage? In other words reach at least 60 Db of isolation? The floor itself is concrete.

The crawl space looks something like this:

116161_20170626_202715_3.jpg

As far as I know there are no serviceable parts in the crawl space and I can have it filled with sand or some sort of insulation material to get rid of the cavity. Don't know how much that would cost though. The height is something like 50 cm lowest to highest point. That's a lot of sand or isolation material for 30 m2 and because the concrete floor is made up of arches, there'll still be some small cavities after filling the space.

Just to be clear: I'm definately going to build a room within a room. If it's not possible to play my acoustic drums in this room, I'll stick with my edrums. The garage in total is 30 m2 and the room within the garage will measure 5m x 2.5m x 2.3 on the inside. Not too concerned with room modes and acoustics as I'm not doing pro recordings and am using amp modeling for guitar.

[Soundman2020]

Hi there "Rain", and Welcome to the forum!

Since there's a (non-accessible and non-vented) crawl space underneath my garage, which will probably act as a big resonant chamber, do you think it's possible to get reasonable levels of sound isolation to play acoustic drums in my garage? In other words reach at least 60 Db of isolation? The floor itself is concrete.

First question: How good do you want this place to be, and how much are you prepared to spend on doing that? The reason I ask is because one option here is to remove that existing floor, and pour a new slab down below. You could even dig a bit more, if you wanted. That would gain you very valuable height in your room, which is important for drums. If you can do that, then it would be your best bet.

Failing that, another option might be blown-in insulation under the existing slab.

How thick is your current concrete slab?

The garage in total is 30 m2 and the room within the garage will measure 5m x 2.5m x 2.3 on the inside.

That's a decent size for a drum room. Nice. Except for the height! If you could sink the floor 70cm, you'd have 3m ceiling height, which would be great.

Not too concerned with room modes and acoustics

You should be! You don't need to make it world-class, of course, but with two dimensions that are directly related ( 5m, 2.5m) you'll have some pretty bad stuff going on at 69Hz, 102 Hz, 138 Hz, 154 Hz, 157 Hz, and several others. Not a happy situation for drums! Compare those frequencies to the fundamental tones of typical kick and floor tom tuning, for example.... not to mention bass guitar... It will be rather unpleasant in there if you don't deal with that. At the very least, you'll need bass trapping to deal with that, and several other things, to make your room pleasant to play in.

- Stuart -

[Rain]

First question: How good do you want this place to be, and how much are you prepared to spend on doing that? The reason I ask is because one option here is to remove that existing floor, and pour a new slab down below. You could even dig a bit more, if you wanted. That would gain you very valuable height in your room, which is important for drums. If you can do that, then it would be your best bet.

First, thanks for your time to answer my question and welcoming me to the forum. Removing the existing floor is not an option because I might sell the house in a couple of years. It would really degrade the value if I have a sub ground level garage Not to mention moisture problems.. The steel garage door will be removed and the entrance will be closed with bricks like the rest of the garage walls. The room will not be directly accessible from the outside to get more isolation. I'll see if I can upload a simple drawing to make it more clear.

Failing that, another option might be blown-in insulation under the existing slab.
How thick is your current concrete slab?

Okay, I'll explore that option of blown in insulation. Might get expensive with 15 m3 of space that must be filled.
The concrete is not a slab. It's made up of concrete arches that are covered with a 3-5 cm screed layer on top for leveling. The overall thickness of the floor is ranging from 10 cm till 30 cm. The arches give the floor it's strength and you can park your car in the garage without a worry. This picture (not mine) might give you a better idea of what my floor looks like from underneath. http://www.regievastgoed.nl/wp-content/ ... pectie.jpg

You don't need to make it world-class, of course, but with two dimensions that are directly related ( 5m, 2.5m) you'll have some pretty bad stuff going on at 69Hz, 102 Hz, 138 Hz, 154 Hz, 157 Hz, and several others. Not a happy situation for drums! Compare those frequencies to the fundamental tones of typical kick and floor tom tuning, for example.... not to mention bass guitar... It will be rather unpleasant in there if you don't deal with that. At the very least, you'll need bass trapping to deal with that, and several other things, to make your room pleasant to play in.

- Stuart -

The only acoustic instruments I'm going to use there is my drums and singing and it will be mostly for practising. Guitar, bass etc. are all over modeling processors or VST's in the pc. My big inspiriation for this is Ritchie Castellano https://www.youtube.com/watch?v=tL_8W4YB8oU His studio is a simple basement, there's almost no sound treatment or bass trapping and he might be lucky with his room but he gets very acceptable recordings.
I can record drum tracks in midi and trigger samples. Would the need come to record my drums, a friend of mine has a great recording room and lives close by. That's why I said that I'm not too concerned with acoustics. First I need the room to be sound isolated.

What's next (or should I say first?) I think I'll start building the room-in-a-room and when that is finished more or less, I'll measure how loud the sound level is when the drums are played inside the room. If it's way too loud, I'll pack up my acoustic drums and only play them on gigs and use the edrums in the room. If the sound isolation is almost there I can look for options to fill up the crawl space.