Soundproof an attiic, rockwool vs special isolation material

[lanzia]

Hi All,

Im looking at possibilities to make a soundproof room on my attic.
It has a sloaping roof and a dormer so that makes it extra difficult to make a a box-in-box construction. As im not verry handy myself Im looking into a company that can do it for me and so far I have 2 options.

The first company is specialized in building custum sized soundproof rooms.
They are using special isolation material called akoesifoam and isofoam.
They can build me a room but its verry pricey and isolation the dormer is not even included.

The second one I found is more something like a one man bussines.
I couldnt really find any references.
I called him and he says he has experience building soundproof rooms, mainly for people playing accoustic piano.
He also came up with a box in a box construction. he is using standard materials like rockwool and compared to the other company he is asking like half the price.

Its verry unclear what I can expect when the room is finished and how good the soundisolation will be.
Im producing dance music and when I put my speakers at normal/acceptable working level the sound (mainly low freq) can be heard 2 floors down in the living room.

Can someone tell if there is much difference in the result between special sound isolation material and rockwool.
If neseccary I rather pay a bit more as long as the result is good. I dont have any technical knowledge of soundisolation myself so im not sure what to chose as I dont know what result I can expect.


Hope someone can advise.

 

[Re-tox_stl]

Rockwoll is usefull for sound absorption, not isolation. For isolation you need a massive air tight room, which is not easy or cheap. Soon enough someone who knows a thing or two will come along with some solid advice, being that my knowledge is very limited. All I know though is that simply putting up rockwoll will not isolate your room.

Drew

 

[lanzia]

Thanks for your reply.
Even though the guys made a plan to build the construction is cheaper then the specialized company its still costs me enough so guess im in right to expect a decent soundisolated room.
Hope its not just a waste of money after all.

More advise is welcome. thanks in advance

 

[Bryan316]

You'll want to make a box inside a box, that transfers neither sound vibration, nor physical vibration. Sound vibration means airtight. Physical vibration means decoupling from other physical connection points. Whoever of your contractors you called mentions building walls decoupled from your other walls, probably knows a lot more about this stuff than the other.

 

[Capriccio]

lanzia, isolation is a scale where soundproof = 100% and 100% is not possible. How soundproof do you need it to be?

You say that you can be heard 2 floors down. What would be helpful is to get a Sound Pressure Level (SPL) meter, have your music playing as loud as you usually want it in your attic, measure the sound pressure from your seat. Let's call this reading 1 and imagine it is 85db. Then, go down 1 floor to the room immediately underneath your attic and measure the sound pressure standing in that room. Let's call this reading 2 and imagine it is 55db.

Check an SPL chart, eg. at Wikipedia, and notice that a very calm room has 20-30db. 20db might be your target to get your noise leakage down to If you want to be making a noise while people are trying to sleep then maybe you will want to get it down to 10db - light leaf rustling, calm breathing. For our example let's go halfway and choose 15db. Take your target level (15db) from reading 2 (55db) and you know that you need to isolate your attic by at least 40db.

You cold go down 2 floors and measure how much sound leaks down 2 floors, just for the fun of it.

Having an understanding of how much sound is leaking and needs be contained gives you a target to work towards. There's no point spending $40,000 if $4,000 will do the job sufficiently.

 

[jhbrandt]

Lanzia,

Determine your current Isolation. This can be done by following the details below:
------
Noise Survey Test

Equipment required:
1) Digital SPL meter with peak hold function
2) package of 20 good quality balloons

Procedure:
a) inflate balloons tightly so that they are the same size.
b) set a reference level by adjusting the SPL meter to 'C' weighting and peak reading. note: popping a balloon can result in and SPL of 105-110 decibels
set the SPL meter on a stand ONE meter from the balloon and pop it. write down this peak reading. This is your reference.
c) set the SPL meter one meter away from the partition to be measured & pop a balloon on the other side of the partition. All doors and windows must be closed or measurements will be null & void. Measure where desired and write down the results.
d) a static measurement can be made either inside the quiet room to measure sound ingress or place the SPL meter outside while music is played to measure sound egress.
e) peak ambiant sound levels can be recorded by placing the SPL meter outside for a specified length of time.

Subtract the results of 'c' from the reference to see the partition STL.
------

Mixing is usually done at/around 85db... tracking drums will reach 105db.

Determine the acceptable level of noise in adjacent spaces and downstairs and go from there.

Have a look at ir761 on my publications page for construction details of wall partitions and ir 586 for floor/ceiling examples.

Cheers,
John