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System Type 4
System Description
In this system type, some level of external signal processing is available, allowing use
of the network in a partially active mode. Although speakers may be mounted in a wide
variety locations in this case, it is recommended that traditional techniques be used
regarding both positioning and placement.
Fully active systems have often been considered to be the most flexible, but they are
certainly not the most effective or practical in all cases. While it is usually considered
best to have individual channels of amplification for each driver, it may not always be
appropriate to use the electronic crossover that is included with many amplifiers today.
This can be especially true for systems where optimum placement or tuning is not
possible, as it may be advantageous to use this network for its various phase correction
and response compensation capabilities. Additionally, digital time correction can be a
complimentary solution to correct for left/right seating position bias, while leaving the
network in place to achieve phase linkage between the woofer, midrange and tweeter.
The only situation where the network might not be used at all, is in a fully active system
with individual channels of amplification, equalization and time correction available for
each driver.
There are essentially three ways to use the network in a partially active mode:
1)Use all functions of the network appropriate for the installation type, but engage an
electronic high-pass on the woofer for increased power handling (usually recom-
mended in systems with subwoofers).
2)If only a limited number of channels or coarse adjustment of digital time correction
is available, use it to compensate for basic left/right seating position bias while using
the appropriate network setting to achieve phase linkage between individual drivers.
3) Bypass particular high-pass or low-pass section of the network in favor of an elec-
tronic crossover, still utilizing the phase and response adjustments of the others.