John Sayers' Recording Studio Design Forum Archive

Question is it better for diffusion or absorbtion to be used in a small vocal room, I want it to sound live not boxed & it sounds boxed right now/ it's partialy foamed up what do you suggest?

You pretty much answered your own question

Foams don't absorb to as low frequency as the semi-rigid fiberglass and mineral wool insulations, and most people don't space ANY of these off the walls to improve the low mid absorption - so what you end up with is a small box, too much bass and low mids, and all the "sizzle" gone. This is what gives you that "boxy" sound.

If you can spare part of one corner for treatment, one way is to build a slat resonator diagonally across a corner; you can tune this for at least one of your "too loud" frequencies, it leaves more highs and absorbs LOTS more low mids, and can add to the "cool" factor as well. Check the Acoustics forum for calculators for this - for a diagonal trap, use the AVERAGE depth from wall for calculations and shoot for around 3-400 hZ.

If you have enough headroom, a couple inches of mineral wool spaced a couple inches off the ceiling will clear up sibilants (and tone them down some) -

HTH... Steve