does somebody has the algorithm to calculate the digital Bessel IIR coefficients up to 48dB for an audio application?
I think there is free software availabe to calculate filter coefficients, no correlation to a STM32 implementation required per se.
And check documentation of the ARM DSP-Lib implementation.
However, I would be wary - the limited precision of float (32 bit / 24 bit) might spoil you implementation, i.e. error propagation might make the filter unstable.
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