4
251 Environmental Speaker 256033
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PTC
Woofer
Twiddlers
33uF, BP
C1
Red
Black
Gray
Green
Yellow
2
1
TEST PROCEDURES
1. Woofer Rub and Tick Test
1.1 Apply a 6 Vrms, 10 Hz signal to the
speaker input terminal. No extraneous noises
such as rubbing, scraping or ticking should be
heard.
Note: To distinguish between normal suspen-
sion noise and rubs or ticks, slightly displace
the cone of the woofer with your fingers. If the
noise can be made to go away or get worse,
it is a rub or tick and the woofer should be
replaced. If the noise stays the same, it is
normal suspension noise and the woofer is
okay. Suspension noise will not be heard with
program material.
2. Air leak Test
2.1 Apply an 8 Vrms, 65 Hz signal to the
speaker input terminal.
2.2 Listen for air leaks around the cabinet
seams, Twiddler™
panel, and the woofer and
Twiddler gaskets. Reposition or replace any
gasket that is found to leak. Repairs made to
the cabinet seam should not be visible from
the exterior of the speaker.
Note: A whooshing noise from the ports at
approximately 65 Hz and 185 Hz is accept-
able (port tuned frequencies).
3. Twiddler Phase Test
3.1 Check the wiring of the Twiddler against
Figures 1 and 2.
4. Sweep Test
4.1 Apply an 8 Vrms, 10 Hz signal to the
speaker input terminal.
4.2 Sweep the signal generator from 10 Hz to
5 kHz and then back to 10 Hz.
4.3 Apply a 3 Vrms, 5 kHz signal to the
speaker input terminal.
4.4 Sweep the signal generator from 5 kHz to
15 kHz and then back to 5 kHz.
4.5 Listen for buzzes, rattles or other noises.
Redress any wire that buzzes; replace the
woofer or Twiddler if they are found to be
defective.
5. Woofer Phase Test
5.1 Observing polarity, momentarily apply 8
VDC to the speaker input terminal.
Note: To avoid damaging the speaker, only
momentarily apply the DC voltage.
5.2 The woofer should move outward with the
application of the DC voltage.
Figure 2. Schematic Diagram
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