Lexicon DD-8+ Owner's Manual page 28

TROUBLESHOOTING AND MAINTENANCE
Audio sounds "thin" and is lacking proper bass response.
Audio Levels differ between channels.
Audio plays and then cuts off.
A humming sound is present in the audio.
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Check to ensure proper polarity of the speaker cables and connections.
Open the Configuration Dashboard
a. Check the Bass control setting in the appropriate processing channel. If set to a minus (-) value,
raise it by at least 3dB.
b. Check the Parametric EQ settings to ensure that bass response has not been reduced for that
channel or pair.
c. Disable all PEQ to see if bass response returns to normal
d. Confirm that the HPF is not enabled on the channel or pair. If it is, reduce the frequency or the
attenuation level.
Check the settings on your preamp, processor or controller.
Check input and speaker connections for short circuits or loose connections at the amplifier and speaker.
Audible hum, or a discernable low frequency noise is one of the most common problems within audio/
video systems. This problem, even when the volume is at a low level, Is usually caused by a common
problem known as a "ground loop". A ground loop occurs when there is a difference in ground voltages
between two or more components that are connected electrically.
In most cases, one or more of the following suggestions below will solve the hum problem.
1. If a cable TV connection is present, disconnect the cable for the wall outlet. If this eliminates
the humming sound, a ground loop isolation device is required. Contact your dealer or cable
provider for assistance.
2. Disconnect components one at a time to isolate the problem. Once the problem is identified,
make sure the associated component is properly grounded and connected to the same
electrical ground as the DD-8+ amplifier.
3. Turn off all components within your system and then disconnect the input cables on the M-8+
amplifier. Turn the amplifier back on. If the hum disappears the fault may be with the input
cables that are being used. Make sure the cables are properly shielded or use a cable that has
better shielding. Make sure the cable is not running or laying on top of any AC power cords.
4. Ground loop problems may also be caused by poor grounding of the electrical system within
your home or may be caused by faulty earth grounds in your home's electrical system. To
isolate the problem, try unplugging components with three prong grounded power cords one
at a time to see if one or all are causing the problem. In the past, cold water pipes and other
utilities were often used for grounds. These items may not be still valid because of corrosion
of the existing pipes and the installation and use of PVC piping. Please check with a licensed
electrician for further evaluation.
DD-8+ Power
Owner's Manual