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CHAPTER 4: ADDING SUBWOOFERS TO A UPQ-1P LOUDSPEAKER SYSTEM
A UPQ-1P loudspeaker system can be deployed with Meyer
Sound self-powered subwoofers (see Table 2). Subwoofers
achieve very low frequency responses and extend the sys-
tem response appreciably, increasing the overall acoustic
power of the system in the lowest frequencies.
The ideal ratio of UPQ loudspeakers to subwoofers depends
on the following variables:
Subwoofer model
System configuration
Frequency content of source material
Headroom required for low frequencies
For most applications, the ratios in Table 2 should yield
good results.
Table 2: Recommended Meyer Sound Subwoofers
Sub-
Frequency
Recommended Ratio
woofer
Response
(Number of UPQs per Subwoofer)
650-P
28–100 Hz
2 x 1
±4 dB
600-HP
39–130 Hz
2 x 1
±4 dB
700-HP
30–125 Hz
2 x 1 for bass-heavy applications
±4 dB
USW-1P
35–180 Hz
1 x 1 for bass-heavy applications;
±4 dB
2 x 1 for flat frequency response
Full-range signals can be connected directly to Meyer
Sound self-powered loudspeakers because the loudspeak-
ers have built-in active crossovers. Subwoofers can be
added to a UPQ system by simply daisy-chaining them to
the UPQ loudspeakers. In more complex systems, subwoof-
ers can be added by using line drivers or digital signal pro-
cessor to send multiple outputs to each sub-system. In
addition, you can use low-cut filters to flatten the overall fre-
quency response of the system while increasing the UPQ
headroom in the lower frequencies.
NOTE:
If the subwoofer's Limit LEDs begin to
light before reaching the required SPL, con-
sider adding more subwoofers to meet the SPL
requirements without exposing the drivers to exces-
sive heat and excursion.
TIP:
MAPP Online Pro™ can be used to accu-
rately predict the appropriate loudspeaker
deployment and subwoofer integration for a loud-
speaker systems, complete with coverage data, sys-
tem delay and equalization settings, rigging
information, and detailed design illustrations. For
more information, see "MAPP Online Pro" on
page 31.
ADDING SUBWOOFERS BY DAISY-CHAINING
When UPQ-1P loudspeakers and subwoofers are daisy-
chained using the Loop connector, the result is a fairly flat
frequency response. However, the response will show an
increase in the 60–200 Hz range where the loudspeakers'
response overlaps at certain ratios (see Table 2).
To add a subwoofer by daisy-chaining:
1. Daisy-chain the suggested number of UPQ loudspeakers
for your subwoofer (see Table 2). Connect the source
signal to the Input of the first UPQ-1P, then connect the
Loop output of the first UPQ-1P to the Input of the sec-
ond UPQ-1P (and so forth).
2. Connect the Loop output of the last UPQ in the chain to
the subwoofer Input.
3. Configure the polarities for the loudspeakers:
If the UPQ loudspeakers and subwoofer are coplanar, or
they are very close together (four feet or less), set their
polarities to the same value. If any of the loudspeakers
have a Polarity switch, set each switch to the up (+) posi-
tion.
If the UPQ loudspeakers and subwoofer are more than
four feet apart, or if a delay is required between them,
use a measurement system like Meyer Sound's SIM 3 to
determine appropriate delay and polarity settings.
CAUTION:
Make sure the source signal is suffi-
cient to drive the total load impedance of the
daisy-chained loudspeakers (see "Loop Connector"
on page 15).
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