audio / HipassBiquadFilter / 0.1.0
A musical highpass filter (two pole recursive, direct form 1). The filter frequency and quality (resonance) can be specified. The filter frequency is expected to be normalized, ie. between 0 and 0.5. The normalized frequency is simply the target frequency divided by the sample rate (eg. 1000Hz / 44100Hz = 0.02267). To let the filter ring out, a number of samples can be specified that will be appended as zeros to the input, and extend the filter response by the same number of samples.

Input parameter:
double[] inputArray, double normalizedFrequency, double gainDb (, int numAppendedSamples)

The input is not modified.