Below are several measurements of square waves taken for a prototype 2-way speaker system comprised of a Vifa P13WH-00-08 and a Morel MDT 30 tweeter. This sepaker was constructed only as a proof of principle. The drivers were chosen for their wide overlap and linear frequency response. The system was designed for a nominal 3K Hz crossover with an overlap paramater of 3.25. Active equalization was used in this prototype, rather than passive equalization, in the form of an SAE 2800 parametric equalizer adujusted to flatten the response in the crossover region. Please see the down-loadable paper for details of the crossover design procedure and the potential for implimentation of passive equalization.
(Note that no details of the specific crossover topology used in the prototype are found there.)
The figures show the response of the system for 350, 480, 727, and 960 Hz square waves. Also shown are the seperate woofer and tweeter response for the 960 Hz case. While not perfect, the result are surprisingly good.
In all cases the measurements were taken with the mic on the design axis and 0.5 m from the speaker. The woofer was in a sealed box of 7 L which yields a Qtc of about 0.5. The tweeter was mounted on a seperate 6-3/4" square baffle, with 33 mm offset to align the acosutic centers of the drivers. No attempt was made to reduce highfrequency diffraction effects from the baffle edges or from the woofer box surface (due to the tweeter offset).
Note that for the 960 Hz case, the first in the harmonic in the Fourier series is at 2940, just about the crossover frequency.
