Specifications

Setting Up The Processing

illustrate the effect of window gating on the control signal that controls the output waveform. The size of the win-

dow can be set to 1dB, 2dB or 3dB with an 'OFF' option to turn the window gating off. Window gating has the

extra advantage in that it enables us to use faster time constants than what would have been possible without

it. Faster time constants have the disadvantage in that the constant re-adjustment of the waveform can become

audible. With a higher window gating setting we are able to reduce the audibility of the faster time constants by

freezing out these changes when the waveform is within our window. Once the waveforms falls outside our win-

dow the faster time constant will track it quickly and effortlessly and then the window gating will kick back in.

Band-couplings

The DSPXtreme band-coupling controls allow us to reduce the effects of the multi-band processing by coupling

the bands to a certain extent. This may be desirable if we want to limit the re-equalisation effects of the multi-

band AGC and limiters. By carefully selecting the coupling ratios we can also reduce any possible spectral

skewing when the processing stages are driven into heavy gain reduction. The multi-band AGC and limiters

each have there own band coupling controls

AGC attacking and decaying with faster time

constants

AGC attacking and decaying with slower time

constants

The effects of time constant speeds

AGC attacking and decaying with faster time

constants

AGC attacking and decaying with faster time

constants but gating enabled

The effects of gating

in dB that the return to rest level is set at.

Window gating is separate from the silence gating that we have been discussing in that it does not work on the

amplitude of the audio, rather the peak to average ratio of the waveform and how the waveform is changing over

time. The window gating feature if enabled freezes the gain over a pre-defined range and will only let gain con-

trol commence once the waveform has fallen outside of this pre-determined range. This is useful because it does

not apply gain correction to audio waveforms that are only changing by small amounts. The images below clearly

AGC attacking and decaying with faster time

constants

AGC attacking and decaying with faster time

constants but with a 2dB window gating setting

The effect of window gating