I am not trying to argue that this response shape can be predicted
from the radiation of a piston in an infinite baffle into half-space. My question was about the nature of the stimulus
used in the simulation itself.
So why should I care about "radiation of a piston in an infinite baffle into half-space" then? Because that's how the on-axis pressure at a point at distance d from the piston is calculated using the Thiele/Small theory. For an ideal sealed or infinite-baffle subwoofer with zero voice-coil inductance, in the T/S theory the passband is the frequency region for which the acceleration amplitude is constant with frequency.
For such a sub, with an applied voltage having a constant amplitude vs. frequency:
- The displacement amplitude vs. frequency has a low-pass characteristic
- The velocity amplitude vs. frequency has a bandpass characteristic
- The acceleration amplitude vs. frequency has a high-pass characteristic (same as the pressure response of the sub itself)
This nature then becomes relevant when such a sub is placed in multiples in a DBA. One might rightly wonder how the subs' response according to the T/S theory is modified by the DBA. I would argue that, to determine such an effect, such a simulation would best be done with a stimulus having a constant acceleration amplitude with frequency.