L-ACOUSTICS XT Manual V1.1 11-02-03 42
As a final check apply a high level sine sweep over the HF compression driver’s operating bandwidth
(for example: 13 volts from 1 kHz to 18 kHz).
Re-mount the entire XT coaxial assembly in its enclosure and perform a system polarity check.
Following service, the damaged compression driver diaphragm should be returned to your distributor
or directly to L-ACOUSTICS for warranty examination.
b) LF Service
The 12” or 15'' loudspeaker components of the coaxial assemblies used in the 112XT and 115XT are
not field-serviceable. For field service, the entire coaxial assembly should be removed and replaced.
To remove the front grille, lift the edges of the acoustic foam and remove the screws. Screws can be
found where the edges of the foam are not glued onto the grille - there is no need to completely
remove the acoustic foam in order to remove the loudspeaker grille.
The damaged loudspeaker should be returned to your distributor or directly to L-ACOUSTICS for
warranty examination and reconing.
c) Polarity Check
Whenever a HF diaphragm or loudspeaker component is replaced, wiring polarity should be checked
with a polarity checking device. Both LF and HF components should operate with positive polarity.
d) Periodic Check
The frequency response of the enclosure should be checked periodically to check for any deviations
due to wear, shock or other damage. This should be done on an annual basis for systems not
subjected to demanding use. For systems being used on a daily basis for sub hire or touring,
enclosures should be checked every month (or even more frequently).
A frequency response check can be performed with a high resolution RTA (real time analyzer), or
preferably using WINMLS, SMAART, SPECTRAFOO, TEF or MLSSA measurement systems. Refer to
the on-axis amplitude/frequency response to determine if your XT enclosure is within specification. In
addition, a response sweep using a sine wave generator is useful for checking for coil rubs, buzzes, air
leaks or other undesirable mechanical vibrations as part of the periodic quality control procedure.
The mechanical attachment of both low frequency and high frequency loudspeakers should be
checked periodically since mount screws can become loose after being submitted to intense, long
duration mechanical vibrations. Similarly, it is a good idea to periodically check that the high frequency
diagram and rear cover for the compression driver are solidly attached. The quality of the contacts
and locking action of the SPEAKON connector should also be checked periodically.
6.2 SPARE PARTS
112XT 115 XT
HP BC121 12" coaxial speaker 8 Ohms HP BC151 15" coaxial speaker 8 Ohms
HS BC31 Diaphragm for 1,4" driver HS BC32 Diaphragm for 1,4" driver
HS BC121 12" recone kit HS BC151 15" recone kit
HR BC121 12" recone kit inc. labour HR BC151 15" recone kit inc. labour
CM 112XT Front foam CM 115XT Front foam
MC 112XTGRL Front grill MC 115XTGRL Front grill
CD COLNEO Neoprene glue 500ML CD COLNEO Neoprene glue 500ML
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