The HIGH/LOW tier crossover (issue #95, "zoom-FFT"): a band centred BELOW this samples the LOW
(decimated) tier when one is present; at or above it, the HIGH tier.
300 Hz is where the HIGH tier's own bins-per-octave stops being the bottleneck rather than an
arbitrary midpoint. Its ~5.86 Hz bins give ~51 bins/octave at 300 Hz, comfortably above even the
finest panel density (640 bands over ~10 octaves ≈ 64/octave). Below 300 Hz that figure falls in
proportion to frequency — ~10 bins/octave at 60 Hz, visibly blocky — while the LOW tier's fixed
~0.73 Hz bins hold ~8× the density all the way down to 20 Hz.
The HIGH/LOW tier crossover (issue #95, "zoom-FFT"): a band centred BELOW this samples the LOW (decimated) tier when one is present; at or above it, the HIGH tier.
300 Hz is where the HIGH tier's own bins-per-octave stops being the bottleneck rather than an arbitrary midpoint. Its ~5.86 Hz bins give ~51 bins/octave at 300 Hz, comfortably above even the finest panel density (640 bands over ~10 octaves ≈ 64/octave). Below 300 Hz that figure falls in proportion to frequency — ~10 bins/octave at 60 Hz, visibly blocky — while the LOW tier's fixed ~0.73 Hz bins hold ~8× the density all the way down to 20 Hz.