JBL DD66000CH-EVEREST II [DD66000CH], User Manual

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sound will result from staggering the bars. The bars select which woofer
receives the low-frequency signals and which woofer receives the midrange
signals. One system should be set to “left” and positioned as
the left speaker system. The other system should be set to
“right” and positioned as the right speaker.
HF Drive/LF Drive
This allows you to switch between normal drive (using a set
of amplifiers) and bi-amp drive (using two sets of amplifiers).
Move the shorting bar only in case of bi-amp driving.
Selection of the Bi-Amp position for the shorting bars bypasses the crossover
function for the full-range woofer and the high-frequency driver. The low-
frequency woofer and the ultrahigh-frequency drivers are unchanged. Use of
this feature requires the addition of an external dividing network to provide the
700Hz primary crossover point for the system. The built-in attenuation and
equalization for the 476Be remains in place. The high-frequency level trim
remains operational, as does battery bias for both the low- and high-frequency
sections. Normally, all three sets of bars (two LF and one HF)
would be moved
together. It is possible to operate the system with just the low-frequency system
or the high-frequency system set to Bi-Amp. In this circumstance, it would be
necessary to use a combination of an external dividing network and the internal
network. However, this is not generally recommended. Figure 6 shows the
low-frequency and high-frequency voltage drive functions necessary to
properly bi-amplify a DD66000 system, using an external dividing network and
two amplifier channels. Neither the low-pass nor the high-pass drive is a
standard Butterworth alignment or, for that matter, a standard alignment at all.
The provided drive curves were derived using the internal passive network and
resulting acoustic low-pass and high-pass shapes. Duplicating these shapes will
result in the same frequency response and directivity pattern as a passive
DD66000. The low pass is made up of two cascaded second-order sections and
the high pass is a single high-pass section. The values within a high-quality
analog dividing network can usually be modified to achieve these results.
Recent digital crossover units will have no problem duplicating these curves.
Figure 6