Specifications

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ADMS 44.22 Installation and Operation Manual
DESCRIPTION
effect is that when program level returns, there are no sudden gain changes
made, as would be the case with a standard compressor/limiter. For effec-
tive ALC operation set the threshold at the very bottom of the dynamic range
of the program level. Setting the threshold too low may cause an increase in
the noise floor of the channel during silence gaps.
• Ratio
The ALC ratio control applies standard compression to the program signal if
the program level exceeds the target output level. When the program level
is below the target output level but above the threshold, the ratio determines
how quickly the ALC adjusts the program to the target output level. Lower
ratios mean slower rates, and higher ratios faster rates. The ALC is most
transparent when operating with low ratios, and is effective even when no
compression is applied (ratio = 1.0). A ratio of 1.2 to 1.5 is recommended in
most applications. Care should be taken with higher ratios, as compressor
‘pumping’ may be heard with certain program material.
Automatic limiting is employed to prevent when the instantaneous program
level + the ALC gain would otherwise cause ALC output clipping.
The limiter is in effect even with a ratio setting of 1.0.
1.2.3 Equalizer
Each input channel is equipped with a fully programmable 3-band equalizer.
Each band can be independently set to be a peaking, high shelf, or low shelf filter,
and can be individually enabled/disabled. Each band’s center (peaking) or corner
(shelving) frequency can be set from 20 Hz to 20 kHz for all supported sample rates
except 32 kHz. At a 32 kHz sample rate, equalizer frequencies are limited to 15.99
kHz. The cut/boost range for all filter types is ± 12.0 dB.
The Q of each peaking filter may be set from 0.2 (wide) to 10.0 (narrow),
while the Q of each high and low shelving filter may be set from 0.2 to 1.0. For
shelving filters, Q values ? 0.8 will create resonance peaks in the area of the corner
frequency. Therefore when working with inputs whose level peaks are near 0 dBFS,
the Q value for these filters should be set < 0.8 to avoid introducing positive gain
into the signal.
1.2.4 Sample Rate Conversion
The ADMS 44.22 is capable of performing high-quality, real-time sample
rate conversion (SRC) on any asynchronous single-wire (2-channel) AES input sig-
nal with sample rates ranging from 32 kHz to 96 kHz for all supported ADMS 44.22
sample rates. Sample rate conversion operates independently for each AES input,
thus making it possible to accept multiple asynchronous digital sources running at
different nominal sample rates. Sample rate conversion can be enabled/disabled on
a channel-by-channel basis.
Any AES signal connected to a channel on which SRC is disabled must be
externally synchronized to the ADMS 44.22 sample clock. External synchroniza-
tion is accomplished through the Word Clock In and Word Clock Out connectors at
the rear of the unit. The ADMS 44.22 cannot synchronize its internal sample clock
to AES inputs.
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