I have wrestled with the equations, and manufacturers' data, but would like some informed, practical advice. I am acoustically treating my newly completed project studio - including extra thick and damped drywalls. My room measures 18' x 12' x 9'. Those dimensions, though either a Sepmeyer or Louden (can't remember) preferred ratio, still exhibit a 33 Hz mode. I may not be able to completely get that, but hope to lessen its higher multiple frequencies. So...the obvious...bass traps and some fiberglass acoustic panels. My questions are specifically about fiberglass acoustic panels: Which is superior in overall performance? And which is superior in low bass mitigation?...a 2" fiberglass panel mounted to the wall, or a 1" panel mounted with a bit of space behind it, or a 2" panel mounted with some space behind it? My reason for the question -- In some cases I have adequate mounting room to mount the panels a bit off the walls / ceilings, and in others it would be a bad idea. Many thanks.