Danny Richie, open baffle loudspeaker and woofer/subwoofer designer at GR Research, is a strong advocate of baffles built to have their resonant frequency outside the passband of the driver(s) mounted on them. He routinely uses two layers of 3/4" MDF on his baffles. Ric Schultz of EVS, who builds OB/Dipole subs and speakers using GR Research woofers and their related Rythmik Direct Servo Control Plate Amp, builds his OB baffles with three layers of MDF----2-1/4" thick!
