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Poor bass performance
• Checkthepolarityoftheconnectionsbetween
the mixer and the subwoofers. You may have
your positive and negative connections reversed
at one end of one cable, causing one subwoofer
to be out-of-phase.
• Checkyoursubwooferpolarityswitchesare
configured appropriately for your setup. See
page 10 for more information.
Poor sound
• Isitloudanddistorted?Makesurethatyou’re
not overdriving a stage in the signal chain.
Verify that all level controls are set properly.
• Istheinputconnectorpluggedcompletelyinto
thejack?Besureallconnectionsaresecure.
Noise
• Makesureallconnectionstothepowered
subwoofers are good and sound.
• Makesurenoneofthesignalcablesarerouted
near AC cables, power transformers, or other
EMI-inducing devices.
• IstherealightdimmerorotherSCR-based
device on the same AC circuit as the HD1501?
Use an AC line filter or plug the HD1501 into a
different AC circuit.
Hum
• Trydisconnectingthecableconnectedtothe
main input jack. If the noise disappears, it
could be a “ground loop,” rather than a problem
with the HD1501. Try some of the following
troubleshooting ideas:
•Usebalancedconnectionsthroughoutyour
system for the best noise rejection.
•Wheneverpossible,plugalltheaudio
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.
If you think your Mackie product has a problem,
please check out the following troubleshooting tips and
do your best to confirm the problem. Visit the Support
sectionofourwebsite(www.mackie.com/support)
where you will find lots of useful information such as
FAQs and other documentation. You may find the answer
to the problem without having to send your Mackie
product away.
Troubleshooting
No power
• Isitpluggedin?MakesuretheACoutletislive
(check with a tester or lamp).
• Ournextfavoritequestion:Isthepowerswitch
on? If not, try turning it on.
• IsthepowerLEDontherearpanelglowing
green? If not, make sure the AC outlet is live. If
so, refer to “No sound” below.
• TheinternalAClinefusemaybeblown.Thisis
not a user serviceable part. If you suspect the
AC line fuse is blown, please see the "Repair"
section next.
No sound
• Istheinputlevelcontrolfortheinputsource
turned all the way down? Verify that all the
volume controls in the system are properly
adjusted.
• Isthesignalsourceworking?Makesurethe
connecting cables are in good repair and
securely connected at both ends. Make sure the
output volume (gain) control on the mixing
console is turned up sufficiently to drive the
inputs of the speaker.
• MakesurethemixerdoesnothaveaMuteon
or a Processor loop engaged. If you find
somethinglikethis,makesurethevolume/
gain is turned down before disengaging the
offending switch.
• Isthethermalindicatorlitredontherear
panel? Make sure there is at least six inches of
free space behind the HD1501.
Appendix A:
Service Information
12
HD1501
HD1501