Multifunction Acoustic Calibrator Type 4226 – User Manual
24
Table 3.6 Expected changes in measured noise dose over a 10-minute period for IEC noise dose meters which record a
100% noise dose for 90 dB lasting 8 hours. Expected changes for all four settings of the Sound Level switch are
shown
Table 3.7 Expected changes in measured noise dose over a 10-minute period for ANSI noise dose meters which record a
100% noise dose for 90 dB lasting 8 hours. Expected changes for all four settings of the Sound Level switch are
shown
3.10 Using the AC Output
The
AC Out
socket provides the electrical equivalent of all the acoustic signals produced in the
coupler with a 12.5 mV equivalent to 94 dB SPL. The one exception is that the test signals for
checking crest factor handling have a crest factor of 10 instead of 3. This is an important exception
since type 0, 1 and I measuring instruments are required to handle crest factors of up to 10, see
section 3.8.
When a plug is inserted in the
AC Out
socket, the coupler is isolated from the signal generator and
the AC output signal itself becomes the feedback signal in the compression loop.
The position of the
Sound Field
switch must be set to Pressure to obtain a constant output level
at all frequencies. Otherwise the signal will be affected by the frequency dependant adjustments
for the various types of microphones and sound fields, see section A.1.
SPL
Setting
Frequency (Hz)
31.5 63 125 250 500 1 k 2 k 4 k 8 k 12.5 k 16 k
94 Inv. A. 5.23 5.23 5.23 5.23 5.23 5.23 5.23 5.23 5.23 5.23 5.23
94 0.00 0.01 0.13 0.72 2.50 5.23 6.90 6.59 4.06 1.94 1.14
104 0.01 0.13 1.28 7.22 25.0 52.3 69.0 65.9 40.6 19.4 11.4
114 0.06 1.26 12.8 72.2 250 523 690 659 406 194 114
SPL Setting
Frequency (Hz)
31.5 63 125 250 500 1k 2k 4k 8k 12.5k 16k
94 Inv. A. 3.63 3.63 3.63 3.63 3.63 3.63 3.63 3.63 3.63 3.63 3.63
94 0.02 0.10 0.39 1.10 2.33 3.63 4.28 4.17 3.11 2.00 1.45
104 0.06 0.38 1.56 4.40 9.31 14.5 17.1 16.7 12.5 8.00 5.81
114 0.25 1.54 6.23 17.6 37.2 58.0 68.5 66.7 49.8 32.0 23.3
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