BootTidal.hs:376-377 applies BOTH:

    gDJF ch = (# lpf (range 180 20000 (fmap (\v -> 1 - 2 * max 0 (0.5 - v)) ...)))
            . (# hpf (range 20   8000  (fmap (\v -> 2 * max 0 (v - 0.5))     ...)))

Yesterday's `left at` column transcribed only the `# lpf` line, so it called
gF3-parked-at-80 "open" when it is really a ~2 kHz HIGH-PASS — which guts a bass
or a voice, and which is exactly the helper PLN had commented off two different
d5 orbits to get the sound back. The report was confidently wrong about the whole
upper half of the knob, in the direction of reassurance.

Now models both bands and grades on the pair:
    0   lpf   180  hpf   20   ⚠⚠ NEAR-SILENT
    64  lpf 20000  hpf   83   open
    80  lpf 20000  hpf 2094   ⚠ thin — low end cut
    127 lpf 20000  hpf 8000   ⚠⚠ NO BODY LEFT
Hard right is not "open". It never was.

Two of the existing tests encoded the old blind spot — they used cc 49 = 100 as
the "safe" control value, which is hpf 4607 Hz. The code was right and the tests
were wrong, so the tests moved to the centre.

And the new test caught something small and real: "centre = true bypass" is an
APPROXIMATION, not an identity. 0..127 is an ODD range, so 0.5 falls between cc 63
and cc 64 and no cc value hits bypass exactly — 63 gives a ~19.7 kHz lowpass, 64
an 83 Hz highpass. Both inaudible, so the knob is fine in practice, but the test
now asserts the truth rather than the comment in BootTidal.hs.

453 tests green across tools/.