I want to use woofer XYZ which has larger Xmax than the 1252DVC. Which other parameters are important?
A4 – I use two drivers to double volume displacement and to reduce even order harmonic distortion by running them with opposite cone motion. The requirements for an open baffle driver are quite different from those for a closed or vented box design. – Fs < 20 Hz - Qts = 0.5 - 0.8 Smaller values of Qts increase roll-off towards the low frequency end and require more equalization than the 6 dB/octave boost for dipole cancellation that I used in the 10-300LP stage of the Crossover/EQ. Most drivers have too strong a motor for dipole applications and are over-damped in an open baffle cabinet. When the driver is mounted into the woofer cabinet, air mass is added to the free-space moving mass of the driver. This lowers the mechanical resonance frequency Fs and increases Qts by approximately the same percentage. The amount of change is difficult to predict accurately and best measured using f0Q0.gif from Ref.12. I do not recommend the use of drivers with very small magnets and Qts >> 0.8 in an
