small snippet for using DSP filters collection...

gistfile1.txt

// usage for DSP
// https://github.com/vinniefalco/DSPFilters

#include "Dsp.h"

// variables...  these filters want a float ** array, so I allocate it like this: 
Dsp::Filter* f;
float* audioData[1];

// 4th order, 50 samples to smooth params, 1 channel
audioData[0] = new float[bufferSize];
f = new Dsp::SmoothedFilterDesign<Dsp::Butterworth::Design::BandPass <4>, 1, Dsp::DirectFormII> (50);

Dsp::Params params;
params[0] = 44100; // sample rate
params[1] = 4; // order
params[2] = 440; // center
params[3] = 100; // band width
f->setParams(params);
        

// assume single channel output, you might have to interleave this if you are doing multichannel output. 

void testApp::audioOut(float * output, int bufferSize, int nChannels){
memset(audioData[0], 0,bufferSize*sizeof(float));
// add something to audioData
f->process(bufferSize, audioData);
memcpy(output, audioData[0], bufferSize*sizeof(float));
}