AmpliVox 260 - Appendix 3 - EMC Guidance & Manufacturers Declaration; Guidance and manufacturers declaration - electromagnetic emissions

OM023-4 Amplivox 260 Operating Manual Page 37
 To calibrate the Right channel (if required) press the RIGHT key (do
not change the amplifier’s volume control)
 Adjust the calibration for all of the right channel frequencies (including
1000Hz) by using the  Hz  keys and the SIGNAL  keys as
described above
 To store the levels and leave Free-field calibration mode, press the
MENU key
 If required, all calibration levels can be set to a default of zero by
pressing the +20dB key while in free-field calibration mode
It is possible that, because of the characteristics of the listening room or
test set-up, the calibration levels above cannot be achieved because the
limit of adjustment is reached for one or more frequencies. Re-
arrangement of the listening room may improve the situation, but if not,
the following is a possible solution:
 Set all of the frequencies for which calibration can be achieved
 For frequencies where this is not possible, adjust each to be a multiple
of 5dBs from the required level
 Produce a correction table for each frequency for which calibration
could not be achieved to be applied to the output level of the
audiometer while conducting a test to relate the instrument display to
actual output level from the speakers.
A2.5.2 Calibrating the Competing Noise Channel
This part of the calibration procedure may be omitted if Free-field speech
calibration is not required.
 Enter the Free-field calibration mode as described in A2.5.1
 Press the SPEECH key and the display will change to indicate the
option to adjust the competing noise calibration level – the legend “Sp
Mask” is used to indicate this
 Without changing the setting on the external amplifier use the SIGNAL
 keys to adjust the level of the competing noise to 90dBSPL as
measured by the SLM using dBA settings.
 Calibrate each channel, pressing the RIGHT and LEFT keys to switch
between channels
 If necessary it is possible to switch between speech (competing noise)
and warble calibration modes by pressing the SPEECH key again
 To store the levels and leave Free-field calibration mode, press the
MENU key