Cut the noise out. Air compressor upsetting others...

[armalites]

This may sound really silly but I would talk to neighbours and ask if it's actually bothering them. When you are close they seem pretty noisy but 5m away that noise may not be that great. I wouldn't mind betting half your neighbours don't even know you are running a compressor. If you are running it at 22:00 then it will sound louder because ambeient noise levels will be lower. Sometimes a bit cooperation goes a long way

 

[DanielW]

I thought egg cartons was used in a DIY sound studios walls?

 

[CRB]

I am sure there will be an acoustic engineer on in a while.

I am curious what the floor is made of that the compressor sits on? If it is coupling to a wood floor, you can be sure that the entire structure will vibrate sympathetically and add to the noise with almost no chance of eliminating it. I have built a few recording studios and for absolute isolation sand is the ideal media. Make a box 6" deep, fill with sand and place a sheet of aspenite (short fibre chipboard) that does not couple to the sides of the box, place compressor here. Coupling vibration will be at a minimum and then you will be able to deal with the walls. In addition to sound insulation any drywall should be mounted on a resilient channel to decouple it from the walls and celing. Additionally, there is lead lined drywall available but in my own studio I doubled up on the drywall. Sound does not move mass very well and following standard acoustic construction principles, you will wind up not hearing a peep from your compressor from the other side of the wall.

Physical de-coupling from the structure (and from itself) is your first step, everything else falls into place when you follow proper acoustic constuction principles...aaaaahhhhh, peace and quiet!!

Told you so

 

[arsenic99]

I thought egg cartons was used in a DIY sound studios walls?

This material is used to reduce 'echo', not provide sound proofing

 

[the snooper]

This material is used to reduce 'echo', not provide sound proofing

to stop sound reflection so it will help to a degree

 

[DanielW]

I've been in a proper sound booth,doesn't half make your ears funny,sorta like puts a slight pressure on the ear drums.

Well thats how I felt about it.

 

[Bearston]

Egg cartons do not affect sound absorbtion, the theory is that the cartons will eliminate standing waves, those that are trapped between parallel surfaces. A recording studio that has resonances that hang around like reverb is useless, there is no control over the sound and elimination of any extraenous and secondary sounds and reflections is paramount. Multiple reflections can easily change the tone of a sound by introducing phase shift of frequencies. (please accept this as the explanation is long and detailed) That is the feeling that DanielW had when he stepped into the vocal booth. In the real world, all those sonic reflections are what give you the information about where you are or where someone or something else is, ie location, directions, etc., the booth eliminates that and focuses the ear, or microphone in this case, because the additional "sonic clues" have been eliminated. I don't use egg cartons, they are a great fire source and look cheesy.
Hanging a compressor by wires and springs will reduce the sound transfer, but not eliminate it, you're still coulped to the structure. Best way to do that would be to create a decoupling hanger, something similar in concept to this:

http://www.muepro.com/shop/category/10581/Vibration-control-hangers.html

Oh yeah, don't forget a cover for the compressor to help hold in all of that sound, too.

 

[Maker]

An "anechoic chamber" is what you want in a perfect world, but they have walls about 2 feet thick.