Meyer Sound UPJunior UltraCompact VariO, Руководство по эксплуатации

Страница: 18 / 44

CHAPTER 4: ADDING SUBWOOFERS TO A UPJUNIOR SYSTEM
18
ADDING SUBWOOFERS WITH A LINE DRIVER
Using a line driver with dedicated low and mid-hi outputs
(like Meyer Sound’s LD-1A and LD-2) to drive a UPJunior
loudspeaker system with subwoofers allows adjustments to
the gain and polarity of each sub-system. This lets you
effectively compensate for the ratio of loudspeakers to sub-
woofers, as well as any acoustical conditions. You can also
engage a low-cut filter on the signal routed to the UPJuniors
to flatten the overall frequency response, minimizing the
gain in the frequency range where the UPJuniors and sub-
woofers overlap while increasing the UPJunior headroom in
the lower frequencies.
NOTE: When using a line driver, if the gains for
the UPJuniors and subwoofer are set to the
same level, the combined response is identical to a
daisy-chained configuration, resulting in a gain in the
overlapping frequency range.
To add a subwoofer with a line driver:
1. Daisy-chain the suggested number of UPJuniors for your
subwoofer (see Table 1). Connect the output of the line
driver to the Input of the first UPJunior, then connect the
Loop output of the first UPJunior to the Input of the sec-
ond UPJunior (and so forth).
2. Connect the low or subwoofer output of the line driver to
the subwoofer Input.
3. To minimized the gain in the frequency range where the
UPJuniors and subwoofer overlap, engage a low-cut fil-
ter for the signal routed to the UPJuniors.
4. Configure the polarities for the loudspeakers:
■ If a low-cut filter is engaged for the UPJuniors, and the
UPJuniors and subwoofer are coplanar or very close
together (four feet or less), a reverse in the polarity for the
subwoofer may be required.
■ If the low-cut filter is engaged for the UPJuniors, and the
UPJuniors and subwoofer are more than four feet apart,
the polarities may need to be reversed again to compen-
sate for delay propagation. In these cases, a measure-
ment system like Meyer Sound’s SIM 3 is recommended
to determine appropriate delay and polarity settings.
GALILEO LOUDSPEAKER MANAGEMENT
SYSTEM
Meyer Sound’s Galileo
®
loudspeaker management system is
a comprehensive solution for driving and aligning loud-
speaker systems, especially those comprised of Meyer
Sound self-powered loudspeakers. The Galileo 616 is a two-
space rack unit with six inputs and 16 low-latency outputs.
Processing for the outputs includes gain, polarity, delay,
high- and low-pass filters, equalization (parametric and
TruShaping), and atmospheric correction.
The Galileo 616 can be controlled from its intuitive front
panel or from the extensive Compass™ software running on
a Windows or Mac
® computer. The Galileo system also
interfaces seamlessly with Meyer Sound’s SIM 3 audio ana-
lyzer.
USING DIGITAL SIGNAL PROCESSORS
Full-range signals can be connected directly to Meyer
Sound self-powered loudspeakers because the loudspeak-
ers have built-in active crossovers. External crossovers and
digital signal processors are optional and should be used
with caution as they can introduce phase shifts that cause
destructive cancellations.
If a digital signal processor is used, both the UPJuniors and
subwoofer should be driven from the same processor to
keep their delay times the same. Otherwise a phase shift
between the UPJuniors and subwoofer may be encoun-
tered. In addition, you should verify the delay time between
channels: some digital signal processors may incur channel-
to-channel delays when the processor is near maximum
throughput, which becomes more likely as the number of fil-
ters in use by the processor is increased.
In no case should a filter higher than the 2nd order be used
on source signals. The additional phase shift introduced by
these filters deteriorates the impulse response, and the
higher roll-off does not improve crossover interaction.
Galileo 616