Specifications

Processing Parameters
18
PROCESSING PARAMETERS
The 'INPUT' menu contains all of the options and parameters relating to the control and conditioning of
the audio inputs.
'SOURCE' This parameter allows you to select the between the analog and digital inputs as the source for
the processing.
'INPUT MODE' This parameter allows you to select different mono options as well as the default Stereo
option. There is also the ability to swap the left/right channels.
'ANALOGUE INPUT A/D CLIP LEVEL' Allows you to set the analogue input level with reference to the
DSPX's A/D converter. This would normally be set to +24dBu if driving the DSPX from professional audio
equipment. This would translate to the wideband AGC being driven to 12dB gain reduction by a 0VU (+4dBu)
audio signal. Make sure that the input audio meters NEVER show clipping under any conditions.
'RIGHT TRIM' This parameter allows you to adjust the right channels gain in small increments to BALANCE
out any small gain discrepancies between the left and right channels. The range is +/- 3dB
'INPUT FAIL SWITCH' This parameter allows you to turn on the silence detection system and specify a
silence time. When enabled this parameter will switch the input source from the primary to the secondary
source when a predetermined length of silence occurs.
'HIGH PASS FILTER' This parameter allows you to select from a variety of high pass filters. You can select
from 20Hz, 30Hz, 40Hz, 50Hz and 60Hz. You also have the ability to bypass the high pass filter with the
'OFF option. The high pass filter can be used to reduce rumble on vinyl or can be effective in removing low
frequency energy that could otherwise cause carrier shift (AFC LOOP) problems in older FM transmitters.
We suggest you leave the high pass filter off unless you have a reason to turn it on.
'PHASE ROTATOR' This parameter if enabled will help to reduce vocal distortion in aggressive presets by
reducing asymmetry in the voice which would otherwise put more workload on the clipping stages. We rec-
ommend enabling this option if you want competitive loudness; otherwise leave it off as the phase rotation
process does colour the sound slightly, although this coloration is often used for artistic effect.
'PRE-EMPHASIS' This parameter allows you to activate pre-emphasis when the DSPX is being used to
process for FM broadcast. The available options are 50 μS, 75 μS and OFF
The 'PROCESS' menu allows access to all of the processing blocks that make up the DSPX. There are
only sub-menus inside the 'PROCESS' menu. The sub menus are laid out in the same configuration as
the signal path through the DSPX.
'WIDEBAND AGC'
The wideband AGC in the DSPX like any automatic gain control device is designed to correct input level
fluctuations and provide a consistent level to the other DSPX processing blocks that follow it. The wideband
AGC in the DSPX is designed to operate in an undetectable, unobtrusive manner similar to a trained opera-
tor controlling a mixing desk. As well as the following user adjustable parameters the wideband AGC incorpo-
rates an assortment of intelligent, adaptive, hidden controls that help keep the gain controlling function of the
AGC as inaudible as possible.
'DRIVE' Controls the drive into the AGC. 0 dB drive corresponds to a gain reduction of 12dB, the mid-
way point, when the input to the DSPX is driven at the nominal 0VU level. The drive can be increased or
decreased by up to 12dB. There probably would be no need to deviate the drive setting from 0 dB under
normal operation.
'ATTACK' Controls the attack rate of the AGC, the time the AGC takes to respond to an increase of input
level. The attack time can be varied between 1 and 10 which corresponds to 100mS to 30S on a semi-
exponential scale.
'DECAY' Controls the release/decay rate of the AGC, the time the AGC takes to respond to a decrease of
input level. The DECAY time can be varied between 1 and 10 which corresponds to 100mS to 30S on a
semi-exponential scale.