Dust extractor noise!

[Kitwn]

More seriously:

When I was looking for ways to soundproof my extractor I did some Googling and found this video on YouTube. I've just managed to find it again. If you don't want to spend the time watching it, the conclusion is that layers of ordinary towels fixed to wooden frames proved surprisingly better at soundproofing ( the authors video-making studio in practice) than genuine acoustic foam. I haven't actually followed up on this so cannot confirm his results but it looks fairly convincing.

https://www.youtube.com/watch?v=pABvTWSxOes&pp=QAA%3D

[Voicecoil]

More seriously:

When I was looking for ways to soundproof my extractor I did some Googling and found this video on YouTube. I've just managed to find it again. If you don't want to spend the time watching it, the conclusion is that layers of ordinary towels fixed to wooden frames proved surprisingly better at soundproofing ( the authors video-making studio in practice) than genuine acoustic foam. I haven't actually followed up on this so cannot confirm his results but it looks fairly convincing.

https://www.youtube.com/watch?v=pABvTWSxOes&pp=QAA%3D

It'll depend a lot on what sort of foam, and how it's mounted; it always tends to work better with an air gap behind it. And also on the character (frequency spectrum) of the noise. If I was trying to silence something like an extractor I'd put it in a rigid box with the input hose coming through a sealed entrance and the output air having to take a zig-zag path through staggered baffles covered in good acoustic foam or Rockwool depending on the character of the noise.