MACKIE SWA2801z - Manual (Page 8)

8
• Make sure the mixer does not have a
Mute on or a Processor loop engaged. If
you find something like this, make sure
the volume/gain is turned down before
disengaging the offending switch.
• Is the thermal protection circuit activated?
Make sure there is at least six inches of
free space behind the SWA801z.
Poor bass performance
• Check the polarity of the connections
between the mixer and the loudspeak-
ers. You may have your positive and
negative connections reversed at one
end of one cable, causing one loudspeak-
er to be out-of-phase.
• Try switching the PHASE switch on
the rear panel. This affects the polarity
between the full-range speakers and the
SWA801z and may improve the low-
frequency response.
Poor sound
• Is it loud and distorted? Make sure that
you’re not overdriving a stage in the
signal chain. Verify that all level controls
are set properly.
• Is the input connector plugged
completely into the jack? Be sure all con-
nections are secure. It’s a good idea to
periodically clean all electrical connec-
tions with a non-lubricating electrical
contact cleaner.
Noise
• Make sure all connections to the active
loudspeakers are good and sound.
• Make sure none of the signal cables are
routed near AC cables, power trans-
formers, or other EMI-inducing devices.
• Is there a light dimmer or other SCR-
based device on the same AC circuit as
the SWA801z? Use an AC line filter or
plug the SWA801z into a different AC
circuit.
Hum
• Try disconnecting the cable connected
to the INPUT jack. If the noise disap-
pears, it could be a “ground loop,” rather
than a problem with the SWA801z.
Try some of the following troubleshoot-
ing ideas:
• Use balanced connections throughout
your system for the best noise rejection.
• Whenever possible, plug all the audio
equipment’s linecords into outlets which
share a common ground. The distance
between the outlets and the common
ground should be as short as possible.