I made a box out of 18mm MDF. Filled it with old duvet and shit. It does work but you can still hear the fucker.
I might look into that with egg box thing too, cheers chew.
Moving the boxed fan into the loft would be an idea aswell
Yes when i was building the room that was my plan, but i`m a big oaf and not reyt agile and same applies to beszt mate and only gujy i trust with things likew this. Cheers BC. 
What's making the noise, the fan or the air emerging from the outlet?
The latter can be reduced by putting the carbon filter on the outlet rather than the inlet, although this will increase the inlet noise.
Perhaps use two?
These might be useful for quitening reflected sound, but they don't have much mass so they might not be much use for blocking transmiited noise/vibrations (mass and isolation are the key words here).
As a substitute, look around for some acoustic damping material - Not the stuff that goes in corners to reduce bass or on walls to reduce reflections, though, but the (sorbothane?) mats used to line speakers or as isolation pads.
It`s no biggi noise coming out into loft, which is why i shoulda put the fan in their to start, but well tis what it is atmo.
It`s only for one more grow cus both my filter and fan are on their last legs, so i really need to get myself new of both before i do another grow really, so i`m thinking of upgrading to a 6inch fan and filter which should then cope with temps using a 600hps in that room during summer, but yes i`ll take a ganders at that stuff, thanks.
hi jimmy mines made from old cord carpet thick as possible wrapped around the rvk and around the ducting and all bound up with a thick layer of gorilla tape my mate has his rvk in a suitcase stuffed with carpet and rockwool and it just looks like luggage on top of a wardrobe and being a old fashioned wood and leather job it work very well and clever i thought,i cannot do that though because i have my res on top the drobe so my rvk is on the back outside the drobe and was fecking loud!the new bigger drobe is great the only noise you hear is a slight rush of air but the wood is bulletproof thick and silences all the rvk noise far better as its a solid back as well imo noise is not reduced to any great benefit with acoustic ducting and it costs more than i am able to afford,good luck
Yes tbh it`s duke i think i`ll knock summink up similar till i got some dosh for another fan n filter, Sweet mate.
cus i seen this on some crazy tv programme when they made an recording studio in a bedroom, might have been a film, feck knows tbh 
