Everything landed. Two full masters differing only in air shelf, both at -14.0 LUFS
/ -0.9 dBTP / LRA 7.5-7.6 / 44100 Hz 24-bit, and 14 split tracks verifying ALL OK.
Duration is 3779.317551 s against a source of 3779.317550 — the load-bearing number,
because it means every one of PLN's playhead calls stays valid and the split lands
exactly where he put the cuts rather than approximately there.

Q1: the missing air is CYMBALS. Drums hold 0.367% of their own energy above 8 kHz
against 0.084% for the runner-up, a 4.4x concentration where evenly-spread energy
would have meant codec hiss. So opening the shelf is licensed by measurement, and
how far is not — hence an A/B rather than a number I liked. The framing that
matters: both candidates are still BELOW typical brightness for electronic masters
(8-16 kHz at 0.40% and 0.63% against a 1-3% norm), so the choice is "quite dark vs
slightly less dark", not "safe vs aggressive". The A/B is also confound-free:
identical loudness, identical true peak, range within 0.1 LU, only the tilt differs.

Q2: the floor is worse here than OPAL. Kick active time averages 44.8% against the
59% project_floor_problem measured for OPAL-26 from real orbit stems, worst at
#2 22.8%, #3 33.4%, #8 36.9%. A stage mic in a room explains it on its own, so this
is a lead rather than a verdict — but it is the first time this gig's floor has been
measurable at all.

Q3, PLN's own question, and the answer is a clean negative: the global pass was not
worth running. Correlations 0.943-0.977 against the per-section stems with level
deltas of at most 0.21 dB. The two separations are the same stems. The prediction
held exactly — htdemucs' 7.8 s receptive field means a global pass cannot give the
model more musical context, so only normalisation differs, and it barely moved. It
cost ~2.5 h of CPU competing with the master render to establish a quarter of a dB.
Sections only next time; the question was worth asking once, not twice.

Side finding: bass is the least stably separated of the four sources (0.9432,
lowest), consistent with the same run putting PunkAChien's bass into `other` — bass
stem at -81.0 dBFS while `other` was the loudest stem in the set.

The log also records three self-inflicted errors that share one shape: checks whose
failure mode was indistinguishable from success. A dropped rtk grep plus a
block-buffered logfile that made a working job look dead, so two renders raced on
the same paths for forty minutes. A speed claim built on counting directories that
appear when writers open. And a scripted edit that silently no-op'd while printing
success unconditionally. Plus the 192 kHz master, which was not a new bug at all —
topic_postprod_mastering has carried that trap since tidal-ears hit it, and I wrote
a new mastering chain without re-reading the omnibus that exists to prevent it.