Mackie HD1501 User Manual

•  Check the polarity of the connections between

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.

•  Check your subwoofer polarity switches are

configured appropriately for your setup. See 
page 10 for more information.

•  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 connections are secure.

•  Make sure all connections to the powered

subwoofers are good and sound.

•  Make sure none of the signal cables are routed

near AC cables, power transformers, or other 
EMI-inducing devices.

•  Is there a light dimmer or other SCR-based

device on the same AC circuit as the HD1501? 
Use an AC line filter or plug the HD1501 into a 
different AC circuit.

•  Try disconnecting the cable connected to the

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:

• 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.

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 
section of our website (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.

•  Is it plugged in? Make sure the AC outlet is live

(check with a tester or lamp).

•  Our next favorite question: Is the power switch

on? If not, try turning it on.

•  Is the power LED on the rear panel glowing

green? If not, make sure the AC outlet is live. If 
so, refer to “No sound” below.

•  The internal AC line fuse may be blown. This is

not a user serviceable part. If you suspect the 
AC line fuse is blown, please see the "Repair" 
section next.

•  Is the input level control for the input source

turned all the way down? Verify that all the 
volume controls in the system are properly 
adjusted.

•  Is the signal source working? Make sure the

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.

•  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 indicator lit red on the rear

panel? Make sure there is at least six inches of 
free space behind the HD1501.

HD1501