Samson EXPEDITION XP40i Owner's Manual page 23

Using the XP40iw Wireless Microphone
reduce the chance of feedback. In general, you can avoid feedback by taking care
not to use any microphone directly in front of a PA speaker (if this is unavoidable,
try using the equalizer to attenuate those high- or mid-range frequencies which
are causing the feedback "squealing").
9. If you hear distortion at the desired volume level, check the rear panel PEAK LED.
If it is lit red, turn down the WIRELESS LEVEL until it lights only occasionally. If you
still hear distortion, do the following:
• T he HT5 transmitter's Gain control has been factory preset to provide optimum
level for the particular microphone model being used and so no adjustment
should be necessary. Any distortion present should therefore simply be a matter
of the microphone being too close to the mouth; try moving it further away. If
this does not solve the problem, use the supplied plastic screwdriver to turn the
Gain control (trimpot) on the HT5 slowly counterclockwise until the distortion
disappears.
Note that following this setup procedure, you can always lower the Volume knob of
the XP40iw in order to further attenuate the output signal if necessary.
10. Conversely, if you hear a weak, noisy signal at the desired volume level (and
with the WIRELESS control of the XP40iw turned fully clockwise), use the supplied
plastic screwdriver to turn the Gain control (trimpot) on the HT5 slowly clockwise
until the signal reaches an acceptable level.
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