pulp::signal::SpectralEnvelope Class Reference

A break-point spectral envelope: gain in dB as a function of frequency, interpolated linearly in the (log2 abscissa, dB) domain — the perceptually correct axes on both sides. More...

#include <additive_spectral_envelope.hpp>

Public Member Functions
void	clear ()
	Removes every break-point.
int	size () const
bool	add (double abscissa, double gain_db)
	Appends a break-point.
double	gain_db_at (double abscissa) const
	Gain in dB at an abscissa.

Static Public Member Functions
static SpectralEnvelope	tilt (double db_per_octave, double reference=1.0)
	Builds a constant-slope envelope — db_per_octave measured from reference — as two break-points spanning the audio band.

Static Public Attributes
static constexpr int	kMaxBreakpoints = 64
	Break-point capacity.

Detailed Description

A break-point spectral envelope: gain in dB as a function of frequency, interpolated linearly in the (log2 abscissa, dB) domain — the perceptually correct axes on both sides.

Fixed capacity, so it is a POD-ish value type that never allocates and can be handed to a prepared bank from the audio thread.

Member Function Documentation

add()

bool pulp::signal::SpectralEnvelope::add ( double abscissa, double gain_db )

inline

Appends a break-point.

Abscissae must be strictly ascending; a non-ascending or over-capacity point is rejected and reported, rather than silently corrupting the interpolation's monotonicity assumption.

clear()

void pulp::signal::SpectralEnvelope::clear ( )

inline

Removes every break-point.

An empty envelope is a flat 0 dB — the identity, so a default-constructed envelope changes nothing.

gain_db_at()

double pulp::signal::SpectralEnvelope::gain_db_at ( double abscissa ) const

inline

Gain in dB at an abscissa.

Outside the break-point span the endpoint value is held rather than extrapolated: extrapolating a slope past the last point is how an envelope quietly produces +40 dB at the top of the bank.

size()

int pulp::signal::SpectralEnvelope::size ( ) const

inline

tilt()

SpectralEnvelope pulp::signal::SpectralEnvelope::tilt ( double db_per_octave, double reference = 1.0 )

inlinestatic

Builds a constant-slope envelope — db_per_octave measured from reference — as two break-points spanning the audio band.

The one envelope shape whose RELATIVE spectrum is pitch-independent in either SpectralDomain, because it is affine in log2 frequency.

Member Data Documentation

kMaxBreakpoints

int pulp::signal::SpectralEnvelope::kMaxBreakpoints = 64

staticconstexpr

Break-point capacity.

[design parameter] default 64; 16 is the documented working size and 2 is the minimum that defines a slope.

---

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

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