# Sidechain Multiband Dynamics Processor LeftRight x8

Detailed: LSP Sidechain Multiband Dynamics Processor LeftRight x8 (SCMBDP8LR)

Formats: CLAP, GST, JACK, LADSPA, LV2, VST2, VST3

Categories: Dynamics

Developer: Vladimir Sadovnikov

Description:

This plugin performs multiband dynamic processing of stereo input signal by applying individual processing to left and right channels separately. Flexible sidechain-control configuration and additional sidechain inputs are provided.

This dynamic processor provides numerous special functions listed below:

- Modern operating mode - special operating mode that allows to look different at classic crossover-based devices. Crossover-based devices use crossover filters for splitting the original signal into independent frequency bands, then process each band independently by it's individual gate. Finally, all bands become phase-compensated using all-pass filers and then summarized, so the output signal is formed. In Modern mode, each band is processed by pair of dynamic shelving filters. This allows the better control the gain of each band.
- Linear Phase mode allows to split audio signal into multiple frequency bands with linear phase shift. This introduces additional latency but gives several benefits:

- Unlike classic crossovers which use IIR (Infinite Impulse Response) filters to split signal into multiple bands and shift the phase of the audio signal at band split points, the Linear Phase allows to use FIR (Finite Impulse Response) filters which are deprived of this.
- Unlike most IIR filters which are designed using bilinear transform, linear phase filters allow to simulate their tranfer function to look like the transfer function of analog filters, without deforming it's magnitude envelope near the nyquist frequency.
- Unlike design of classic Linkwitz-Riley filters, the design of IIR filters provides shorter transition zone of the filter.

- Sidechain boost - special mode for assigning the same weight for higher frequencies opposite to lower frequencies. In usual case, the frequency band is processed by gate 'as is'. By the other side, the usual audio signal has 3 db/octave falloff in the frequency domain and could be compared with the pink noise. So the lower frequencies take more effect on gate rather than higher frequencies. Sidechain boost feature allows to compensate the -3 dB/octave falloff of the signal spectrum and, even more, make the signal spectrum growing +3 dB/octave in the almost fully audible frequency range. This is done by specially designed +3 db/oct and +6 db/oct shelving filters.
- Lookahead option - each band of gate can work with some prediction, the lookahead time can be set for each channel independently. To avoid phase distortions, all other bands automatically become delayed for a individually calculated period of time. The overall delay time of the input signal is reported to the host by the plugin as a latency.
- Up to 8 bands are available for use, each band is not attached to it's strict frequency range and can control any frequency range. Also, each band can be controlled by completely different frequency range that can be obtained by applying low-pass and hi-pass filters to the sidechain signal.

Controls:

- Bypass - bypass switch, when turned on (led indicator is shining), the plugin bypasses signal.
- Mode - combo box that allows to switch between the following modes:

- Classic - classic operating mode using IIR filters and allpass filters to compensate phase shifts.
- Modern - modern operating mode using IIR shelving filters to adjust the gain of each frequency band.
- Linear Phase - linear phase operating mode using FFT transform (FIR filters) to split signal into multiple bands, introduces additional latency.

- SC Boost - enables addidional boost of the sidechain signal:

- None - no sidechain boost is applied.
- Pink BT - a +3db/octave sidechain boost using bilinear-transformed shelving filter.
- Pink MT - a +3db/octave sidechain boost using matched-transformed shelving filter.
- Brown BT - a +6db/octave sidechain boost using bilinear-transformed shelving filter.
- Brown MT - a +6db/octave sidechain boost using matched-transformed shelving filter.

- Link - the name of shared memory link used to receive sidechain signal
- FFT L, R In - enables FFT curve graph of input signal on the spectrum graph.
- FFT L, R Out - enables FFT curve graph of output signal on the spectrum graph.
- Filters L, R - enables drawing tranfer function of each sidechain filter on the spectrum graph.
- Zoom - zoom fader, allows to adjust zoom on the frequency chart.

'Signal' section:

- Input - the amount of gain applied to the input signal before processing.
- Output - the amount of gain applied to the output signal before processing.
- Dry - the amount of dry (unprocessed) signal passed to the output.
- Wet - the amount of wet (processed) signal passed to the output.
- Dry/Wet - the knob that controls the balance between the mixed dry and wet signal (see Dry and Wet) and the dry (unprocessed) signal.
- In - the input signal meter.
- Out - the output signal meter.

'Analysis' section:

- Reactivity - the reactivity (smoothness) of the spectral analysis.
- Shift - allows to adjust the overall gain of the analysis.

'Split Left' and 'Split Right' sections - allow to quickly control all bands and provides most frequently used controls for Left and Right channels of stereo signal independently:

- Band - allows to enable the corresponding band, band #0 is always enabled.
- Range - allows to adjust the start frequency of the frequency range controlled by the band.
- Controls - set of buttons that control the behaviour of the compressor:

- On - enables compressor assigned to the corresponding frequency band.
- S - turns on soloing mode to the selected band by applying -36 dB gain to non-soloing bands
- M - turns on muting mode to the selected band by applying -36 dB gain to it
- Sidechain combo - allows to select external sidechain inputs or shared memory audio stream

- SC Preamp - applies additional gain to the sidechain band.
- Makeup - applies additional gain to the output of the corresponding dynamic processor.
- Attack Time - attack time of the compressor.
- Release Time - release time of the compressor.
- Ratio Low - the compression/expansion ratio of the curve at the low level of signal.
- Ratio High - the compression/expansion ratio of the curve at the high level of signal.
- Threshold - the settings for each of four available thresholds for the corresponding dynamic processor.

'Band N' section - allows to simultaneously control all parameters of dynamic processor of Left and Right channels assigned to the selected frequency band:

- Sidechain Source - allows to set the sidechain source

- Internal - the audio inputs of plugin are used as sidechain signal.
- External - additional sidechain audio inputs of plugins are used as sidechain signal.
- Link - the shared memory link is used to receive sidechain signal.

- Sidechain Mode - combo box that allows to control sidechain working mode:

- Peak - peak mode.
- RMS - Root Mean Square (SMA) of the input signal.
- LPF - input signal processed by recursive 1-pole Low-Pass Filter (LPF).
- SMA - input signal processed by Simple Moving Average (SMA) filter.
- Middle - middle part of signal is used for sidechain processing.
- Side - side part of signal is used for sidechain processing.
- Left - only left channel is used for sidechain processing.
- Right - only right channel is used for sidechain processing.
- Min - the absolute minimum value is taken from stereo input.
- Max - the absolute maximum value is taken from stereo input.

- Sidechain Lookahead - look-ahead time of the sidechain relative to the input signal.
- Sidechain Preamp - pre-amplification of the sidechain signal.
- Sidechain Reactivity - reactivity of the sidechain signal.
- Sidechain LCF - button turns on the low-cut filter for the sidechain signal and knob allows to control the frequency of the filter.
- Sidechain HCF - button turns on the high-cut filter for the sidechain signal and knob allows to control the frequency of the filter.
- Dynamic Processor Left/Right On - enables corresponding dynamic processor assigned to the corresponding frequency band.
- Dynamic Processor Left/Right Solo - turns on soloing mode to the selected band by applying -36 dB gain to non-soloing bands.
- Dynamic Processor Left/Right Mute - turns on muting mode to the selected band by applying -36 dB gain to it.
- Dynamic Processor Left - additionally draws the sharpened curve model for the left channel.
- Dynamic Processor Right - additionally draws the sharpened curve model for the right channel.
- Dynamic Processor Ratio Low - the compression/expansion ratio of the curve at the low level of signal.
- Dynamic Processor Ratio High - the compression/expansion ratio of the curve at the high level of signal.
- Dynamic Processor Makeup - additional amplification gain after processing stage.
- Dynamic Processor Attack - default attack time of the dynamic processor.
- Dynamic Processor Release - default release time of the dynamic processor.
- Dynamic Processor Hold - the time period the envelope holds it's maximum value before starting the release.
- Dynamic Processor Gain - the amount of gain applied to frequency band by the compression curve.
- Dynamic Processor Ranges - allows to configure up to four additional knees, attack and release ranges:

- Thr - Knob that enables additional knee.
- Att - Knob that enables additional attack range.
- Rel - Knob that enables additional release range.
- Thresh - Threshold of the additional knee, works only if corresponding Thr button is turned on.
- Gain - Gain of the additional knee, works only if corresponding Thr button is turned on.
- Knee - Softness of the knee, works only if corresponding Thr button is turned on.
- Attack - Pair of knobs that allows to adjust the attack threshold and attack time of the additional attack range. The new attack time is applied if the envelope is over the specified threshold. Otherwise the attack time of previous range or default attack time (if there is no previous range) will be applied.
- Release - Pair of knobs that allows to adjust the release threshold and release time of the additional release range. The new release time is applied if the envelope is over the specified threshold. Otherwise the release time of previous range or default release time (if there is no previous range) will be applied.