Specifications

SECTION 5
B-CHAIN ALIGNMENT
5.1 Check Theater Equipment
Thoroughly check the loudspeakers and power amplifiers for sources of poor
performance:
• Check that the loudspeaker cables are in good condition and that they of a
suitable gauge for the impedance of the speakers and the length of the run.
• Rattles (a leak in the low frequency driver cabinet may appear to be a rattle).
• Loose bolts or other hardware.
• Open drivers.
In systems with pairs of drivers – low frequency or high frequency – one
voice coil of the pair may be open but the system will still function.
Check the speakers with an ohmmeter. If one channel requires markedly
more equalization than the other or if one speaker overloads at lower
levels than the other speakers, an open driver circuit could be the cause.
• Missing drivers or other components.
• The settings of the crossovers to match the type of drivers in use and the
acoustics of the theater.
The high frequency driver level control must be set for the best possible
frequency response before you attempt any equalization. This is also true if
the system uses active crossovers with bi-amp equipment.
• Phasing between the low frequency and high frequency drivers, and between the
channels.
• Aiming of speakers.
Check that the speakers are correctly aimed into the auditorium, and that
they are not obstructed by the screen frame, struts or other obstructions.
• Check that speakers are correctly connected; that the speaker on the left is
connected to the left power amplifier.
Amplifiers
• Distortion.
• Gross gain differences among amplifiers.
If one amplifier differs in performance from the others, it should be checked
and repaired, if necessary, before proceeding further. Input gain controls
should all be at the same setting.