Soundproofing and acoustic questions for my room

Dozemusic

New member
Hello :)

I plan to turn a room in a control + tracking room.

Dimensions are 5m x 4.6m x 2.9m.

I am on a 1000$ budget (for the soundproofing, we'll have more for acoustic treatment), and with the construction materials available around the best i can do is :

Build a room in a room with one layer of thin drywall and 100mm of fiberglass on a wooden structure 5 to 10 cm from the original wall.

So i theoretically end up with a 4.6m x 4.3m x 2.75m room.

BUT

I will also angle the ceiling up from the front of the room by 12° for 3.41m and then down again by a 12° angle to the back of the room for the last 1.19m (=4.6m).

I will also angle the right and left walls the same way but 6° each.

The plan is to reduce flutter echo AND for the (thin) drywall with empty corners and fiberglass behind to act as a room wide basstrap.

The floor is carpeted and I will add thick fiberglass absorbers and wooden diffusers to fine tune the acoustics.

The original walls are 3 concrete walls and 1 drywall (behind the back-wall with the door). The room is on the ground floor so the structure would be resting on the industrial concrete foundation of the building.

After we build this, if we are not satisfied with the soundproofing (thought we don't need it to be perfect), we might in the future add one layer of drywall with green glue.

Does it sound good?

I also wanted the front wall (behind the speakers) to have a V shape pointing inwards, towards the sweet spot, with the two slopes at 6° or 12°, because there is a 15cm structural pole from the building at the center of the front wall just behind the future drywall and i dont want to lose too much space by pulling the whole front wall inwards by 15cm. By angling the two sides of the wall the pole would be inside the "V". Also, i reckon this would allow reflexions to be sent away from the listener (as there will be two 1sq.m windows incorporated in the drywall on the right and left of the front wall that could cause lots of early reflexions).

Thank youuuuu :)

The plans for the wooden frame (NOT PROPORTIONAL, rely on the annotated dimensions and angles) :

Screen_Shot_2017_05_19_at_12_59_43.png
 
With 3 concrete walls and concret floor, do you really need soundproofing? Are you trying to keep sound out or sound in? SO you are not building a 'false' floor? Sound will transmit through any solid junction, so you would need to isolate the walls from the concrete floor.
 
How noisy is it around your studio? Also how far away are people that may be disturbed by the noise from the studio. I ask because $1000 is never going to build a room within a room.

Alan.
 
With 3 concrete walls and concret floor, do you really need soundproofing? Are you trying to keep sound out or sound in? SO you are not building a 'false' floor? Sound will transmit through any solid junction, so you would need to isolate the walls from the concrete floor.

How noisy is it around your studio? Also how far away are people that may be disturbed by the noise from the studio. I ask because $1000 is never going to build a room within a room.


Hello!

We already use the room as a studio. There is a school next door and the kids screaming make quite a lot of noise. It is also to keep sound from reaching the facilities on the floor above. It's ok if there is some spill, we just need to reduce it.

Actually we budgeted all the materials (wood, drywall, fiberglass, joints, screws, paint...) and the total cost is 1000$.

It's funny because i posted this question on three different forums and people always answer that maybe I don't need to soundproof or that 1000$ is not enough for the materials. But we KNOW that we want to soundproof and we don't need a floating floor so it's just half a room within a room, and 1000$ is enough to build it.

I read everywhere that a massive concrete floor on a solid bedrock does a good job at absorbing sound without transmitting it back, and that is why i think that building a floating floor is not necessary and I should save the money.

Are the angles and dimentions described in my post good? Could the thin drywall and fiberglass act as a room-wide basstrap? Is there a risk that the structure resonates? How can i prevent it? Would it be a good idea to build it on neoprene pads?

Thanks :)
 
OK, If the floating floor is out, build a floating drum floor, then place and the amps on isolation mats. I suggest this as there will be transmission of low frequencies into the building structure via the floor to the walls, if you reduce this due to the building being very solid their won't be a problem.

Build stud walls inside the concrete walls, I built this is an earlier studio of mine that was below a house with very solid walls, I put the bottom frame of the stud walls on top of a rubber isolation strip, and used minimal fixings along the bottom that were not completely tightened. Not tightening then is not a problem as they only stop the walls moving sideways. Any fixings to the original building structure I did with thin tin metal brackets to reduce transmission.

The ceiling is a different issue, what structure is the ceiling at the moment, how strong? Can you install a hanging ceiling?

With drywall, you can buy high density drywall, usually called sound block or something like that. It is much heavier than standard drywall and stops a lot more low end. 2 layers on the walls and another layer at least over the original drywall wall.

If you use high density insulation between the stud wall and the original concrete walls you wont loose as much space, however having an air gap between the insulation and the concrete will help with the noise transmission.

Remember the room has to be air tight or the sound will get in/out, and you need to think about ventilation / air con?

Doors also need to be air tight and very solid, double doors even better.

Alan.
 
OK, If the floating floor is out, build a floating drum floor, then place and the amps on isolation mats. I suggest this as there will be transmission of low frequencies into the building structure via the floor to the walls, if you reduce this due to the building being very solid their won't be a problem.

Yeah!

Build stud walls inside the concrete walls, I built this is an earlier studio of mine that was below a house with very solid walls, I put the bottom frame of the stud walls on top of a rubber isolation strip, and used minimal fixings along the bottom that were not completely tightened. Not tightening then is not a problem as they only stop the walls moving sideways. Any fixings to the original building structure I did with thin tin metal brackets to reduce transmission.

The ceiling is a different issue, what structure is the ceiling at the moment, how strong? Can you install a hanging ceiling?

I'm not even going to fix the studs, they'll be placed on a rubber strip and the new ceiling will be build over the studs, as if the new structure was a whole different box in the original room, apart from the floor that will be the original floor (as in the plans in my original post).

Will it resonate? Are the angles specified in my original post right?
 
Resonate? If you mean will the walls resonate, try to make sure that the insulation is against the drywall so that the drywall does not resonate. When I built the stud wall I put wire on the back side of the stud wall frame to keep the insulation against the dry wall. This was because I wanted to keep an air gap between the insulation and the original building wall.

If you mean will I get a build up of frequencies within the room, study the building ratios maybe one of these is achievable, if not try to get close. This link is full of building information and room size information, you don't need to buy the products but the information is very helpful.

Regarding angled walls, I have built past studios with angled walls, but I think it is not really required, create the angles with bass trapping and broadband absorbers, my current studio has got angled walls at one end but I did that due to the room being a long narrow room and I was trying to avoid the long slap back, in fact I built the angled walls with a very low end bass trap by putting only one layer of drywall and a ton of insulation / air gap / insulation inside, with a very solid back to it, it works.

Cheers
Alan.
 
Hey! Thank you very much for the advice and the Acoustic 101 pdf!

I'll look into all of this, (and build a rectangular room without angled walls!)
 
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