How to cast from IIRCoefficents to array of float

[daniel]

I haven’t read your code, but you probably have to check your maths and in which range the numbers are:
gain = 0 => dB = -infinity (defaults to -80.0, can be specified)
gain = 0.5 => dB = - 6dB
gain = 1 => dB = 0

so you can simply map to your rect:

auto y = jmap (Decibels::gainToDecibels (magnitude, -80.8f), -80.0f, 0.0f, rect.getBottom(), rect.getY());

BTW. I think this thread will be interesting for you:

FFT Amplitude

It has been a while since I used an FFT and instead of porting some old C# sharp code I’m trying out juce’s. Here’s what I understand: The frequency of bin[x] = Fs / nth Record. In the past I have multiplied the real and imageinary parts but using fft::performFrequencyOnlyForwardTransform only modifies the array going in. Is the data in that array a linear amplitude? My other question is if say the FFT is (10th Order) 512 bins do I need to supply 512 or 1024 samples? (my guess is that if its…