AXYS
®
Octadrive DSP-DN User Manual rev 2.0
201703/ODSPDN_2.0
15
level Controls
The gain of each analogue input and each digital input
may be adjusted independently over the range -70 dB to
+20 dB. For the analogue line inputs the nominal input
level with 0 dB gain is 0 dBV, and the maximum input level
is +21 dBV (peak).
The source of DSP audio input 1 and 2 (either analogue or
Dante
™
) is software configurable.
The level of each output channel can also be set
independently, with a range of 80 dB.
Note that after the inputs have been summed, there is also
a master level control (in the Volume tab of WinControl),
which provides a single-point adjustment of the levels at
all outputs, and a separate Analog output gain setting,
which selects “low-gain” (0 dB) or “high-gain” (+14 dB)
modes.
Polarity (phase) inversion is also available for each input
and output.
EQ Adjustment
The DSP section provides very comprehensive signal
equalisation for both inputs and outputs. Each analogue
input, each digital input and each output channel has its own
4-band parametric equaliser. These provide up to 25 dB of cut
or boost per band (depending on filter type selected) over the
range 10 Hz to 24 kHz, with per-band selection of filter type.
Output equalisation can be used to construct crossover
filtering to allow the Octadrive DSP-DNs to be used with
multi-way loudspeaker systems. Input equalisation permits
tailoring of individual input signals for optimum clarity.
In addition to individual input and output equalisation,
there is an overall 8-band parametric equaliser in the main
volume control stage, which affects all inputs and outputs.
Each band has the same characteristic as those of the
input and output equalisers.
Delay
Delay may be inserted in any or all of three locations in the
audio signal chain.
Each output channel may have up to 43.6 s of delay.
Additionally an overall unit delay of up to 21.8 s may be
inserted at the main volume control stage. Furthermore
each analogue input may have up to 1.3 s of delay.
Autogain
The DSP section includes an autogain algorithm which can be
set to automatically adjust the overall volume level according
to the ambient noise level detected by a microphone
connected at the ANS mic input. The algorithm measures
the ambient noise in gaps in the programme material being
fed via the Octadrive DSP-DN. Once enabled, the amount
of additional gain per dB of ambient noise increase can be
controlled, as well as the threshold at which gain adaption
begins. Note that this feature is not available when the mic
input is used for paging.
SURVEIllANCE FUNCTIONS
The Octadrive DSP-DN incorporates various surveillance
features to ensure continuous operation in critical
applications.
The surveillance functions described in this
section do not encompass all device features.
Auto-Input Switching
Normal configuration of the Octadrive DSP-DN is for all
sixteen inputs to be permanently summed, so that signals
on all enabled inputs are always fed through the system.
However, if wished, priorities may be assigned to individual
inputs so that audio through the system is normally derived
from one input only. The inputs are then monitored, either
for presence of pilot tone, or for a continuous signal level
above a pre-determined threshold. In the event of non-
detection of the pilot tone or input signal, the signal source
can be switched to that on an alternative input.
This arrangement is primarily intended to provide
redundancy; by utilising more than one audio distribution
path, a high degree of system of security can be gained.