Date: 2017-06-28
PPA DSP amplifier user manual
30
Figure 17 XOV Settings for Subwoofer and Satellites
For output 1, we set the high-cut frequency to 400 Hz with a slew-rate of 24 db/Oct. For outputs 2 and 3, we use
the same value as low-cut and set a high-cut at 20 kHz with Butterworth characteristic.
Now set the amount of FIR filter coefficients. A total of 2048 taps is available. As low frequencies require longer
filters, we use 1024 taps for the subwoofer path and 512 taps each for the satellites.
Additionally, we activate the
total
tickbox for channel one and two in the
curves
section. This displays the output
frequency and phase responses of the amplifier outputs. The orange curve represents output 1, the green one is
output 2. These responses are calculated from the speaker measurement and the applied FIR crossover filters
(and optional EQs/IIR filters and gains), that is, you see the frequency response of an imaginary measurement of
speaker and DSP amp on axis.
The latency can be adjusted. This latency is the exact latency of the filter combined with the speaker. You can
play with the setting and see how low you can adjust the latency without compromising the overall response or
the linear-phase. The filter calculation algorithm automatically adjusts the frequency at which the overall system
will be linear-phase to match the latency.