Sound proofing rooms

[Sekhmet]

Not sure if this belongs in here or Off Topic but i thought i'd try here.

Anyways, with the Summer coming up it's become increasingly more obvious that the room we practise in is not insulating enough of the sound when we practise so i figured i'd ask here for any information/guides you know of that would help.

At the moment we just have a timber framed room with regular plaster board insulated with celetex, on the walls inside i have a mixture of carpet and egg boxes (the egg boxes did nothing towards sound insulation). There's a 2ft thick wall off cob on one side and a wood shed on another, and then a row of rooms down the other side, the front door and window point towards about 50 acres of field and a woods.

This does cut out a portion of the sound but its still noisey if your with in about 10 to 20 metres.

We were thinking of building an internal room to create an air gap, but we want to be doubly sure first if this is the best way as it's costly (even though we get products at trade).

Thanks for your help.

Mikey

[TwilightOdyssey]

http://www.dynamat.com/

[Dreichlift]

This is what I did and it worked pretty well, get carpet (I used carpet sample squares that a local carpet shop had discarded). Line the walls with the carpet then cover this with egg boxes, over this use more carpet preferably something thick and fluffy not carpet tiles as they tend to be too hard, alternativly see if you can hang some heavy velour curtains about 2 to 3 inches in front of the carpeted and eggboxed wall. Bear in mind any windows or vents will allow sound to leak out, however the heavy curtains "should" help prevent this without you suffocating or passing out with heat stroke.

I've also heard that there is something called "acoustic blanket" that works better than the curtain but I am just assuming you have to work to a budget. hope it helps

[TwilightOdyssey]

Do NOT use carpeting! It results in a very boomy room acoustic.

[Dreichlift]

Do NOT use carpeting! It results in a very boomy room acoustic.

yes it does if you use a carpet which is quite stiff with a short pile, but a deeper fluffy carpet like 70's shagpile kills any acoustic reverberation. One thing I did think of in the night though is Eggbox style foam. I've not actually used it but I have seen plenty of professional studios with it on the walls. Also acoustic laboratories use a similar method in their acoustic chambers for testing speakers etc. It should be fairly easily available as I understand furniture makers use it for cushions, mattresses and headboards.

[TwilightOdyssey]

I don't know where you studied room acoustics, but I'm going to have to disagree.

a deeper fluffy carpet like 70's shagpile kills any acoustic reverberation

This is not true.

You can only do 3 things to a soundwave:

Refect it. This can be done with any hard surface.

Absorb it. This is done with certain acoustic fabrics. The deeper the note, the deeper the acoustic 'trap' needs to be.

Diffuse it. This is accomplished with an uneven surface (even a bookshelf full of books can to this) that breaks up the sound wave before it can be reflected back into the room.

The longer a wave is, the less frequently it repeats, thus the lower its frequency. Low frequency waves travel right through doors and walls. Just stand 50 ft away from a car with a subwoofer blasting inside it and you will see what I mean ... the closer you get to the car, the less you will feel the bass.

The shorter a wave is, the more frequently it repeats, thus the higher its frequency. High frequencies are much easier to absorb, reflect, or diffuse than low frequencies.

90% of all sound escapes through doorways and windows. The best way to keep soundwaves from leaving a room are to seal it (weather sealed doors and windows) and create a barrier of air which will trap low frequencies and prevent them from traveling.

When you use something like carpeting, which is meant for running your toes through not putting on your walls, on your wall, you prevent  high frequencies from escaping the room, but low frequencies pass right through. Carpeting is not tuned to reflect only unwanted frequencies.

The same can be said for egg crate. The pattern of egg crates is designed to hold eggs, not to reflect certain frequencies and diffuse others.

The last thing you want to do to any room is deaden the inside of it with one fabric. It is better to design the room properly from the ground up.

I design acoustic spaces for a living, so I know a little bit of which I speak. Misinformation like 'line the walls with shag carpeting' isn't the way to procede. Soundproofing a room requires a lot of forethought and some degree of construction skills. Then you tune the space to your needs depending on what you are going to use the space for. Deadening a room with material that is not meant to be used acoustically is worse than leaving the room as it is now.

I apologize for over-simplifying the subject, but that's the idea in the broad strokes. And Dreichlift, I'm not flaming you. The road to Hell is paved with good intentions, however.

I can recommend several solutions for you, Sekhmet.

[Dreichlift]

Certainly, I was just providing budget solutions using materials Sehkmet already had or may have access to. There are many ways to address the problem these days and many far more effective than the old ways.