Low Shelf Filter

Overview

Low shelf second-order IIR (Infinite Impulse Response) filter. All frequencies below the shelving frequency are either boosted or attenuated by the specified gain in decibels. This filter is embodied by the lowshelf class.

Include

#include <q/fx/biquad.hpp>

Declaration

struct lowshelf : biquad
{
         lowshelf(double db_gain, frequency f, float sps, double q = 0.707);
   void  config(double db_gain, frequency f, float sps, double q = 0.707);
};

Expressions

In addition to valid expressions for biquad, lowshelf allows these expressions.

Notation

ls

Object of type lowshelf.

f

Object of type frequency.

sps

Floating point value representing samples per second.

q

Q or quality factor.

g

gain (in decibels).

a [, b, c, d]

Required a, optional b, c, d.

Constructor

Expression Semantics

lowshelf(g, f, sps [, q])

Construct a lowshelf from g, f, sps and optional q (defaults to 0.707).
C++ brace initialization may also be used.

Mutators

Expression Semantics

ls.config(g, f, sps [, q])

Configure a lowshelf from g, f, sps and optional q (defaults to 0.707).