Function convert_optimised 

pub fn convert_optimised(wav: &Wav) -> ConvertedIr

The optimised conversion: a PEDAL_IR_TAPS-tap filter (the part of an upload the pedal plays) with the whole IR’s 1/6-octave magnitude response, instead of the IR’s first 2048 samples cut off by the pedal after 384. The file is resampled with resample (windowed sinc); the filter is minimum-phase (no leading delay, energy packed into the start), refined over a few iterations, then fitted tap by tap to the full IR’s band levels. Its level is the one the app means to give the IR (app_gain on the IR’s first 2048 samples from its onset), matched over 100 Hz – 8 kHz. The unused part of the upload is zero.