26
TEST PROCEDURES
FreeSpace
®
DS 40SE Surface-Mount
Loudspeaker
Note: For the air leak, rub and tick, and
power sweep tests, all listening will be done
at a distance not to exceed 1 foot if the
ambient noise is greater than 65 dBA SPL.
An air leak is considered to exist when
audible to the inspector while facing the
baffle of the speaker assembly. Leaks that
are only audible by reorientation of the
speaker assembly from this position are
considered acceptable.
1. Air Leak Test
1.1 Remove the loudspeaker grille using
disassembly procedure 1. Set the TAP rotary
switch to the 8 Ohm position.
1.2 Apply a 9 Vrms, 100 Hz signal to the
8 Ohm input of the loudspeaker.
1.3 Listen for air leaks around the drivers,
baffle and input terminal area. Re-align or
replace any leaking gaskets. Replace any
driver that has a rubbing or ticking noise.
2. Rub and Tick Test
2.1 Remove the loudspeaker grille using
disassembly procedure 1. Set the TAP rotary
switch to the 8 Ohm position.
2.2 Apply a 9 Vrms, 30 Hz signal to the
8 Ohm input of the loudspeaker.
2.3 Listen to the drivers for any rubbing,
ticking or other extraneous noise. Replace
any defective driver. Small ticks are accept-
able if they cannot be heard at a distance of
one foot.
Note: There is a normal suspension noise.
To distinguish between a rub or a tick and
suspension noise, displace the cone slightly
with your finger. If the rubbing can be made
to go away or get worse, it is a rub or a tick.
If the noise stays the same, it is suspension
noise.
3. Power Sweep Test
3.1 Remove the loudspeaker grille using
disassembly procedure 1. Set the TAP rotary
switch to the 8 Ohm position.
3.2 Apply a 12.75 Vrms, 75 Hz signal to the
8 Ohm input of the loudspeaker.
3.3 Slowly sweep the oscillator frequency
from 60 Hz to 5 kHz. Listen for any buzzes,
rattles or other extraneous noises from the
drivers or from the internal parts. Test sweep
time should be about 3 seconds up and 3
seconds down. Replace any driver that has
a buzzing noise.
Note: The whooshing noise from the port at
around 75Hz is acceptable.
4. Transformer TAP Select Test
4.1 Apply a 70 Vrms, 100 Hz signal to the
70/100V loudspeaker input.
4.2 Slowly change the TAP selection switch
from the 40W position to the 2.5W position.
A decrease in audio output level should be
heard for each descending TAP position of
the switch.
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