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2. The Sub LP crossover is temporarily extended from 100Hz to 500Hz. The sub output
gain is then ramped to a pre-determined level. The Output gain is then adjusted as
before, to achieve a reference level at the Mic. This gain (SubGainRef) is stored, as is
the difference between the final meter reading and the desired target
level(SubRefDiff). An FFT is then carried out on the Sub and the average level is
stored (SubZeroLine).
before, to achieve a reference level at the Mic. This gain (SubGainRef) is stored, as is
the difference between the final meter reading and the desired target
level(SubRefDiff). An FFT is then carried out on the Sub and the average level is
stored (SubZeroLine).
3. Pink noise is passed through 20Hz to 100Hz crossovers and into the main system
amplifier. The Cal output gains are ramped to the level stored in Step 1. The
difference between the level measured at the input (Fed from main amp “Sub Out”)
and the output level is stored as MainSysGain and is a measure of the position of the
Volume control on the users amplifier. The signal is band-limited to ensure that an
amplifier with a band-limited sub output will read the same as an amplifier that does
not band-limit it’s sub output.
difference between the level measured at the input (Fed from main amp “Sub Out”)
and the output level is stored as MainSysGain and is a measure of the position of the
Volume control on the users amplifier. The signal is band-limited to ensure that an
amplifier with a band-limited sub output will read the same as an amplifier that does
not band-limit it’s sub output.
4. When the above steps are complete, enough data has been obtained to set the final
output gain for the sub so that when both systems are excited from the main
amplifier, (fig. 3) the mean sub level is at the same amplitude as the reference level in
the main response.
amplifier, (fig. 3) the mean sub level is at the same amplitude as the reference level in
the main response.
Main Amplifier
preAmp
LineIn
SubOut
Sub Amplifier
MainAmp
PRBS
CalGain
Cal Out
Mic In
AEQ Measuring Configuration
SubGain
SubAmp
Figure 2
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