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Crossover Filter

Audio crossover filter

  • Library:
  • Audio System Toolbox / Filters

Description

The Crossover Filter block implements an audio crossover filter, which is used to split an audio signal into two or more frequency bands. Crossover filters are multiband filters whose overall magnitude frequency response is flat.

Ports

Input

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  • Matrix input –– Each column of the input is treated as an independent channel.

  • 1-D vector input –– The input is treated as a single channel.

Data Types: single | double

Output

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Available if Number of crossovers is set to 1, 2, 3, or 4. Port Y1 always corresponds to a lowpass filter.

Data Types: single | double

Depending on the number of crossovers specified, port Y2 outputs the original audio signal passed through a bandpass or highpass filter.

Available if Number of crossovers is set to 1, 2, 3 or 4.

Data Types: single | double

Depending on the number of crossovers specified, port Y3 corresponds to a bandpass or highpass filter of the original audio signal.

Available if Number of crossovers is set to 2, 3 or 4.

Data Types: single | double

Available if Number of crossovers is set to 3 or 4.

Data Types: single | double

Available if Number of crossovers is set to 4.

Data Types: single | double

Parameters

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If a parameter is listed as tunable, then you can change its value during simulation.

If you specify multiple crossovers, the corresponding Crossover frequency (Hz) and Crossover order parameters populate in the dialog box automatically.

The number of bands output by the Crossover Filter block is one more than the Number of crossovers.

Number of CrossoversNumber of Bands Output
1two bands
2three bands
3four bands
4five bands

Tunable: No

Crossover frequencies are the intersections of magnitude response bands of the individual two-band crossover filters used in the multiband crossover filter.

Tunable: Yes

The crossover filter order relates to the crossover filter slope in dB/octave: slope=N×6, where N is the crossover order.

Tunable: Yes

The plot is updated automatically when parameters of the Crossover Filter block change.

Tunable: Yes

When you select this parameter, the block inherits its sample rate from the input signal. When you clear this parameter, you specify the sample rate in Input sample rate (Hz).

Tunable: No

Tunable: Yes

Dependencies

To enable this parameter, clear the Inherit sample rate from input parameter.

  • Interpreted execution — Simulate model using the MATLAB® interpreter. This option shortens startup time and has simulation speed comparable to Code generation. In this mode, you can debug the source code of the block.

  • Code generation — Simulate model using generated C code. The first time you run a simulation, Simulink® generates C code for the block. The C code is reused for subsequent simulations, as long as the model does not change. This option requires additional startup time but the speed of the subsequent simulations is comparable to Interpreted execution.

Tunable: No

Algorithms

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The Crossover Filter block is implemented as a binary tree of crossover pairs with additional phase-compensating sections [1]. Odd-order crossovers are implemented with Butterworth filters, while even-order crossovers are implemented with cascaded Butterworth filters (Linkwitz-Riley filters).

References

[1] D’Appolito, Joseph A. "Active Realization of Multiway All-Pass Crossover Systems." Journal of Audio Engineering Society. Vol. 35, Issue 4, 1987, pp. 239–245.

Introduced in R2016a

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