FAQ's will be added as questions are submitted to
SEALING THE CONDUIT:
I am using Lubell swimming pool speaker
(underwater). I am facing difficulty to water proof connection
of cable through conduit hub. Is there any requirement of cable
gland to fix in 1/2" conduit hub? --NM
designed for underwater luminaries / speakers have flooded
conduit design by nature. It is for this reason that the
opposite end of the conduit must be elevated above the pool's
water line (as dictated by Local, National, and International
Electrical Code -- 8" minimum typical) and terminated inside a
junction box. If the pool is in a location not subject to
freezing, then generally no additional precautions are required.
If pool is in location subject to freezing, then conduit/hub
area inside wet-niche is sealed with sealing compound (as
prescribed by Local, National, International Electrical Code),
and RV type anti-freeze is poured inside sealed conduit as
QUESTIONS ABOUT SUITABLE AMPLIFIERS:
Can any amplifier be used to power the 9484
in wall pool speaker?
A "Class AB"
amplifier rated up to 78 watts rms @ 8 ohms (25 Vrms) may be
used to power one or two of the 9484-25V-*** underwater speaker
kits, providing amplifier has UL or ETL listing label, and has a
three prong power cord connected to a grounded GFCI power outlet
per National Electrical Code. Each LL916 UW speaker /
AC205B transformer box circuit presents a 16 ohm reactive
(capacitive) load; Multiple circuits must be wired in parallel
only, observing minimum impedance rating of amplifier.
Commercial sound amplifiers having 25V output (NOT 70V output!)
may be used -- allow 37.5 watts
power consumption for each Lubell LL916-XXX speaker and AC205B
transformer connected in parallel to the 25V line.
The USA version of the monaural Bosch
PLE-1P120-US amplifier (Class AB) provides a 25V constant
voltage speaker connection and 120 watt power rating, allowing
connection of up to three paralleled Lubell 9484's (37.5W x 3 =
112.5 watts total), which does not exceed the amplifier's 120
watt rating, or the 9484's 25 Vrms maximum rating.
The USA version of the monaural Bosch
PLE-1P240-US amplifier (Class AB) provides a 25V constant
voltage speaker connection and 240 watt power rating, allowing
connection of up to six paralleled Lubell 9484's (37.5W x 6 =
225 watts total), which does not exceed the amplifier's 240 watt
rating, or the 9484's 25 Vrms maximum rating.
The stereo Samson Servo 200 amplifier
(Class AB) is rated at 66 watts per channel @ 8 ohms ( 22.98
Vrms), allowing connection of either one 9484 (16 ohms) or two
9484's in parallel (8 ohms) to each channel of the amplifier.
Although the amplifier is rated at 4 ohm minimum load,
experience has shown that connecting more than four speakers to
this amplifier can result in instability at certain frequency
ranges.. so not recommended.
can you advise me if we can connect 9484 in-wall UW
speakers to Tesira 4175R amplifier or if not, do you
have solution to do so?
Answer: The Tesira amplifier (Class D) is rated at 175
watts @ 8 ohms (37.42 Vrms) which greatly exceeds the 9484's
25 Vrms maximum rating, and would likely result in rapid burn
out of the underwater speakers. Amplifier is also Class D (not
recommended) with no mention of stability when driving
reactive loads. We would not recommend using this amplifier!
Can an L-pad or autoformer volume control be installed between
the speaker/transformer and the amplifier?
The Lubell underwater speaker is a reactive piezoelectric
speaker providing a primarily capacitive load to the
amplifier. Inserting a variable resistor or autoformer
between the capacitive speaker and the amplifier will result in
an alteration of the frequency response as the volume is
changed. For this reason, use a remote volume control that
changes line level signal to the amplifier.