pulp::signal::LpgT< SampleType > Class Template Reference

Vactrol-modelled low-pass gate. More...

#include <lpg.hpp>

Public Member Functions
void	prepare (SampleType sample_rate)
void	set_decay_ms (double ms)
	Dark-recovery time.
void	set_rise_ms (double ms)
void	set_colour (SampleType c)
	0 = pure VCA (the filter stays wide open), 1 = pure filter (the gain stays at unity), between = both.
void	set_range_hz (SampleType min_hz, SampleType max_hz)
	The effective ceiling is additionally capped at sample_rate / 4 when the cutoff command is applied — see the note in process().
void	set_droop (SampleType d)
void	strike (SampleType level)
	Ping the cell.
void	set_gate (SampleType level)
	Sustained control level, for idiom 4.
void	reset ()
SampleType	process (SampleType input)
SampleType	control () const
	Conditioned cell state, 0..1 — the value both the amplitude and the cutoff are derived from.
SampleType	commanded_cutoff_hz () const
	Last cutoff command applied to the owned filter.
SampleType	cutoff_hz () const
	Compatibility spelling for the cutoff telemetry.

Static Public Member Functions
static SampleType	velocity_to_strike (SampleType velocity)
	Map a 0..1 velocity to a strike level whose loudness and brightness rise together the way a struck object's do.

Static Public Attributes
static constexpr double	kRiseMs = 1.5
	Photoresistor light-onset time constant.
static constexpr double	kStrikePulseMs = 3.0
	Length of the light pulse a strike() produces, at two rise time constants.
static constexpr SampleType	kVcaExponent = SampleType{1.5}
	Control-to-amplitude power law.
static constexpr SampleType	kDefaultFcMinHz = SampleType{40}
static constexpr SampleType	kDefaultFcMaxHz = SampleType{12000}
static constexpr SampleType	kMinFcHz = SampleType{10}
static constexpr SampleType	kMaxFcHz = SampleType{20000}
static constexpr double	kDefaultDecayMs = 150.0
static constexpr SampleType	kDefaultDroop = SampleType{0.5}
	How much the closing slows as the cell darkens.
static constexpr SampleType	kMaxDroop = SampleType{0.95}
static constexpr SampleType	kVelocityCurve = SampleType{0.7}
	Velocity-to-strike exponent for idiom 2.

Detailed Description

template<typename SampleType = float>
class pulp::signal::LpgT< SampleType >

Vactrol-modelled low-pass gate.

Member Function Documentation

commanded_cutoff_hz()

template<typename SampleType = float>

SampleType pulp::signal::LpgT< SampleType >::commanded_cutoff_hz ( ) const

inline

Last cutoff command applied to the owned filter.

The value is useful for metering or visualising the brightness component of the coupled response. Reset, processing, and cutoff-affecting setters keep it synchronized.

control()

template<typename SampleType = float>

SampleType pulp::signal::LpgT< SampleType >::control ( ) const

inline

Conditioned cell state, 0..1 — the value both the amplitude and the cutoff are derived from.

Useful as a modulation source in its own right.

cutoff_hz()

template<typename SampleType = float>

SampleType pulp::signal::LpgT< SampleType >::cutoff_hz ( ) const

inline

Compatibility spelling for the cutoff telemetry.

prepare()

template<typename SampleType = float>

void pulp::signal::LpgT< SampleType >::prepare ( SampleType sample_rate )

inline

process()

template<typename SampleType = float>

SampleType pulp::signal::LpgT< SampleType >::process ( SampleType input )

inline

reset()

template<typename SampleType = float>

void pulp::signal::LpgT< SampleType >::reset ( )

inline

set_colour()

template<typename SampleType = float>

void pulp::signal::LpgT< SampleType >::set_colour ( SampleType c )

inline

0 = pure VCA (the filter stays wide open), 1 = pure filter (the gain stays at unity), between = both.

set_decay_ms()

template<typename SampleType = float>

void pulp::signal::LpgT< SampleType >::set_decay_ms ( double ms )

inline

Dark-recovery time.

50-500 ms is the musical range; the value is the one-pole time constant of the closing, before the droop lengthens it.

set_droop()

template<typename SampleType = float>

void pulp::signal::LpgT< SampleType >::set_droop ( SampleType d )

inline

set_gate()

template<typename SampleType = float>

void pulp::signal::LpgT< SampleType >::set_gate ( SampleType level )

inline

Sustained control level, for idiom 4.

Held until changed; a strike briefly overrides it upward.

set_range_hz()

template<typename SampleType = float>

void pulp::signal::LpgT< SampleType >::set_range_hz ( SampleType min_hz, SampleType max_hz )

inline

The effective ceiling is additionally capped at sample_rate / 4 when the cutoff command is applied — see the note in process().

set_rise_ms()

template<typename SampleType = float>

void pulp::signal::LpgT< SampleType >::set_rise_ms ( double ms )

inline

strike()

template<typename SampleType = float>

void pulp::signal::LpgT< SampleType >::strike ( SampleType level )

inline

Ping the cell.

The strike accumulates onto whatever charge is left, which is idiom 3.

velocity_to_strike()

template<typename SampleType = float>

SampleType pulp::signal::LpgT< SampleType >::velocity_to_strike ( SampleType velocity )

inlinestatic

Map a 0..1 velocity to a strike level whose loudness and brightness rise together the way a struck object's do.

Member Data Documentation

kDefaultDecayMs

template<typename SampleType = float>

double pulp::signal::LpgT< SampleType >::kDefaultDecayMs = 150.0

staticconstexpr

kDefaultDroop

template<typename SampleType = float>

SampleType pulp::signal::LpgT< SampleType >::kDefaultDroop = SampleType{0.5}

staticconstexpr

How much the closing slows as the cell darkens.

0 is a plain exponential; the default gives the lengthening tail that separates a struck object from an RC circuit. Capped below 1 because a droop of 1 would stall the decay at zero instead of reaching it.

kDefaultFcMaxHz

template<typename SampleType = float>

SampleType pulp::signal::LpgT< SampleType >::kDefaultFcMaxHz = SampleType{12000}

staticconstexpr

kDefaultFcMinHz

template<typename SampleType = float>

SampleType pulp::signal::LpgT< SampleType >::kDefaultFcMinHz = SampleType{40}

staticconstexpr

kMaxDroop

template<typename SampleType = float>

SampleType pulp::signal::LpgT< SampleType >::kMaxDroop = SampleType{0.95}

staticconstexpr

kMaxFcHz

template<typename SampleType = float>

SampleType pulp::signal::LpgT< SampleType >::kMaxFcHz = SampleType{20000}

staticconstexpr

kMinFcHz

template<typename SampleType = float>

SampleType pulp::signal::LpgT< SampleType >::kMinFcHz = SampleType{10}

staticconstexpr

kRiseMs

template<typename SampleType = float>

double pulp::signal::LpgT< SampleType >::kRiseMs = 1.5

staticconstexpr

Photoresistor light-onset time constant.

kStrikePulseMs

template<typename SampleType = float>

double pulp::signal::LpgT< SampleType >::kStrikePulseMs = 3.0

staticconstexpr

Length of the light pulse a strike() produces, at two rise time constants.

This is the parameter that produces idiom 3: a cold strike reaches about 86% of the strike level, and a strike landing on a decaying cell starts from whatever is left, so successive hits in a roll climb. A pulse much longer than the rise time would saturate the cell and the accumulation would vanish.

kVcaExponent

template<typename SampleType = float>

SampleType pulp::signal::LpgT< SampleType >::kVcaExponent = SampleType{1.5}

staticconstexpr

Control-to-amplitude power law.

kVelocityCurve

template<typename SampleType = float>

SampleType pulp::signal::LpgT< SampleType >::kVelocityCurve = SampleType{0.7}

staticconstexpr

Velocity-to-strike exponent for idiom 2.

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The documentation for this class was generated from the following file:

• /home/runner/work/pulp/pulp/core/signal/include/pulp/signal/lpg.hpp