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TRI-AMPED PA CABINETS WITH SUBWOOFER (refer to illustration at right)
Use: Application Example
This is highly generalized, but shows the main idea in cre-
ating larger systems. In this example, the audio source ma-
terial is connected to the inputs of all four DSP’s. Take care
to keep right and left channel signals connected to the cor-
rect channels of downstream equipment. For example, keep
all left channel signals routed through the channel 1 sec-
tions of downstream gear and all right channel signals
routed through channel 2 sections of downstream gear. This
preserves stereo imaging.
Each DSP would be setup independently with the appropri-
ate crossover response and equalization for the specific
driver being used. Refer to the speaker’s (or driver’s) docu-
mentation for recommended frequency range, drive level,
and any other applicable information. In the example at right,
DSP #1 (assigned to high frequency drivers) might be set up
for a high pass filter with a -3dB point of 6 kHz and high-
speed limiters to protect them from transients. DSP #2 (as-
signed to midrange drivers) might be set for a band pass
filter, with -3 dB points at 1 kHz and 7 kHz using mild signal
limiting. DSP #3 (assigned to low frequency drivers) might
provide a 45 Hz to 1100 Hz bandpass with EQ to remove
modal resonances of the listening environment. DSP #4
(subwoofer drive) could be assigned a low pass filter with a
-3dB point of 50 Hz and equalization as required. All the
filters mentioned above would have assignable response
type (where applicable) and assignable slope characteris-
tics enabling precise tuning of the system.
Power requirements for high frequency drivers are gener-
ally much lower than for low frequency drivers; this requires
either reduced gain in the signal processing stage or the
lower power amplifier for the high frequency drivers. The
opposite is true for the subwoofers; they generally require
the highest power to drive them, so assign your most pow-
erful amplifiers to the lowest frequency drivers. Assign your
amplifiers to the drivers according to the required power
levels .