µ-Dimension Glow DSP8 Instruction Manual page 41

caused by a cancellation in the response. This can be due to multiple
speakers playing the same frequency but having them out of phase at
the microphone location. It could be caused by a reflection off a hard
surface, where the direct sound arrival from the speaker and the
reflected sound off the hard surface arriving slightly later combine to
cancel the response at that frequency.
Regardless, if the frequency response shown on the RTA display
does not move in direct correlation with the changes being made on
the EQ controls, you will not be able to correct the problem with EQ.
You will need to use speaker polarity, crossover frequency/slope,
signal delay, etc. to correct the problem. If you determine it is due to
a reflection off a hard surface, physical adjustments to the speaker
placement, moving or modifying the hard surface, etc, may be
required.
In the end, you may choose not to address some frequency response
issues. As always, use your ears to confirm what actually sounds the
best. Just because an RTA gives you a particular visual frequency
response on the display does not
Page 40