Acoustic Rolloff:
- Acoustic high-pass determined by:
- Fs – Free air resonance of a driver
- Qts – Bandwidth of driver resonance
Fs and Qts can be obtained by manufacturer Thiele-Small specs or derived by an impedance chart if available:
- Acoustic low-pass:
- Determined by things such as motor force, suspension, and (namely) inductance.
- If the inductance (essentially resistance to current, for our purposes) is high, the output of the speaker is less, regardless of the axis.