https://docs.juce.com/master/tutorial_dsp_convolution.html
Implement the cabinet simulator
In the prepare() function, call the prepare function of the convolver in the processor chain [4].
private:
//==========================================================================
enum
{
convolutionIndex // [2]
};
juce::dsp::ProcessorChainjuce::dsp::Convolution processorChain;
};
Should be:
void prepare (const juce::dsp::ProcessSpec& spec)
{
processorChain.prepare(spec); // [4]
}