- Jan 12, 2017
- Oslo, Norway
You may be thinking of the depth required for resistive absorption to address bass frequencies. Toole discussing a RPG QRD: "At 7.9 in. (0.3 m) deep and exhibiting useful diffusion down to about 300 Hz, they appear to meet the requirements for wideband diffusers"
Geddes: "It appears then that the best rooms for serious listening would have a large amount of low frequency absorption accompanied by very low amounts of high frequency absorption... the directional source can be pointed in such a way that the first reflection actually arrives at the ear opposite the direct arrival. For the directional source, the secondary (after the first) reflection arrivals are virtually all lateral and behind the listener – a good thing." His solution is to have highly directional (90 degree coverage pattern) speakers toed-in severely to cross significantly in front of the listening position so that the first lateral reflection is actually contralateral and consequently later, not early.
Thanks a lot for clarifying!