Posted by Wayne Parham on September 28, 2002 at 13:27:56

In Reply to: SPICE and Piezo Questions posted by JohnB on September 28, 2002 at 07:20:09:

If you put resistance in series with a primarily capacitive load such as a piezoeletric tweeter, the resistance will definitely have an effect on the AC behavior of the circuit. It forms a low-pass filter that will show up in Spice in the AC analysis. To make the model even more complete, you might want to add tank circuits that emulate its resonances. You'll notice one at 5khz, for example.

About the source voltage and impedance in Spice models, you can set this to whatever values you prefer. Source voltage is whatever you want it to be, and source impedance can be modeled using an input resistor.

As for the mechanical resonance of the two π tower, the cabinet is 4.5ft³ and the Helmholtz frequency is 40Hz.