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Tr o u b l e s h o o t i n g
Room Correction problems
This section gives suggested solutions to typical problems that
may occur when using Meridian Room Correction. If problems
still persist after working through the following steps please send
an email to support@meridian.co.uk with a zip file containing
your MSL file. Please also supply details of the loudspeakers and
amplifiers you are using.
Failed microphone/SPL meter test
During the first measurement a microphone test is performed
to ensure that the power and SNR (signal to noise ratio) are
acceptable. The larger the SNR the better the measurement.
The following sections describe some of the most likely problems
which will cause the power and SNR values to go outside these
ranges.
Power result "Bad"
This indicates that there is very little or no signal on the connector
you have chosen as your microphone input.
• Check that there was sound from the front left speaker during
the test.
If in doubt, repeat the measurement. If there is still no sound check
the connections from the digital surround controller to the left
loudspeaker. Switch the digital surround controller off and then
on again, select Calibrate as described in the installation guide
for your digital surround controller, and check that the left speaker
plays the calibration signal.
• Ensure that the lead from the SPL meter is intact.
• Check that the SPL meter is switched on and set to the 90dB
band, or the band which includes 90dB, and with C weighting.
If the loudspeakers measured less than 75dB SPL during the
calibration phase it may be better to use the 80dB range.
• Check that the lead from the SPL meter is connected to the
correct input,
A8 (L) on the G68.
• Ensure that the Sensitivity setting is adequate for the SPL meter
or microphone.
The sensitivity value for analogue inputs is given in rms volts
(Vrms). For example, a sensitivity of 1Vrms allows a signal of
2.8Vpp. A sensitivity of 1V is recommended for use with most SPL
meters though 0.7V may be preferable for those with lower level
output.
Power OK, SNR result "Bad"
The most likely cause of this problem is that an analogue source is
connected to the input chosen for the microphone.
• Check that the lead from the SPL meter is connected to the input
you have chosen for the microphone test.
Another possibility is that the lead from the SPL meter is in bad
condition and only making a poor connection.
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