[Lefatshe]

Look at how wonderful these cardboard forms would be as a diffuser!!!  My wife just received a shipment from Nakedwines.com and this is how they hold the bottles in the box.

[JLM]

The material doesn't 'look' acoustically opaque so they wouldn't offer much of a barrier to sound traveling through it and therefore not provide significant diffusion.  Plus they aren't random depths, so would only diffuse at one frequency (approximately 1600 Hz from my guess of about 4 inch depth). 

Here's a link to plans for a much better inexpensive (but heavy) diffuser:

http://www.pmerecords.com/Diffusor.cfm

[gab]

or here:

http://www.oliverprime.com/prd/?show=calculator

http://www.diyaudio.com/forums/construction-tips/269366-easy-diy-depot-sound-diffuser-panels-step-step.html

http://www.mh-audio.nl/DiffusorCalculator3.asp?km=3.56&kl=30.48&calc=Calculate+Diffuser#result

[Lefatshe]

VERY little reverberation. About $100 for used shutters from ReStore. $150 for used billboards hung from ceiling - soft walls.  Hardware store vinyl lattice on ceiling with lots of holes.

[eichlerera1]

Lefatshe,

I have those particular wine inserts (and other wine inserts) as well as egg cartons and foam squares completely covering all my walls and ceiling. In addition I use large rolled up carpets in the corners.
I assure you-all that they are FANTASTIC diffusers!