High Pass Filter Producing Buzz Sound

Audio Plugins
1

I’m new here and I was trying to make a highpass filter plugin, but for some reason it keeps producing a buzz sound. Can someone please tell me what I’m doing wrong please?

This is my processBlock function:

    processBlock (AudioBuffer<float>& buffer, MidiBuffer& midiMessages)
{
    auto totalNumInputChannels  = getTotalNumInputChannels();
    auto totalNumOutputChannels = getTotalNumOutputChannels();
	for (auto i = totalNumInputChannels; i < totalNumOutputChannels; ++i)
		buffer.clear (i, 0, buffer.getNumSamples());
	for (int channel = 0; channel < totalNumOutputChannels; ++channel)
	{
		float* channelData = buffer.getWritePointer(channel);
		mFrequencySmoothed = mFrequencySmoothed - 0.4*(mFrequencySmoothed - mFrequencyParameter->get());
		filter->setCoefficients(IIRCoefficients::makeHighPass(getSampleRate(), mFrequencySmoothed));
		filter->processSamples(channelData, buffer.getNumSamples());
	}
}

This is how I created the filter pointer and my prepareToPlay function:

IIRFilter *filter;
void prepareToPlay (double sampleRate, int samplesPerBlock)
{
	filter = new IIRFilter();
}
2

You need to have a separate filter instance for each audio channel you are processing. (So 2 filter objects for stereo etc…)