Reported: pegging the TRAX fader changes nothing audible, the ladder never reaches red, and the
ladder does not scale with the fader.
Cause (two defects in the same setters):
- UserGain wrote the OUTPUT DEVICE's volume. NAudio's WaveOut ignores that, so the fader was inert.
- LocalGain (the desktop-mute follow) recomputed the sample-chain volume WITHOUT the user gain, so
every duck/mute silently discarded whatever the creator had set.
Fix: one `EffectiveVolume(user, local)` = MusicVolume × user × local, applied to the sample chain by
both setters. The meter sits AFTER that stage, so the ladder now scales with the fader and can reach
the peak band on a loud track — exactly what pegging should look like. Max user gain is +6 dB, so
"pegged" means the file at unity, not a magic boost.
Guard: MusicLevelTests pins the arithmetic (default half, pegged double, mute multiplies to zero),
that the user gain survives the mute follow, and that nothing may drive the output device's volume
again — the no-op that made this invisible.
Reported: the TRAX bar moves, but its sampling looks far slower than the mic meter.
Cause: the TRAX number was a raw instantaneous peak per metering block — a stutter sampled by the UI
timer, with no smoothing. The mic looks fluid because it is smoothed at audio-callback rate.
Fix: the player now smooths its measured level with the SAME curve the mic uses
(MeterScale.NextLevel: fast attack, gentle decay), and the dock's meter clock runs at ~30 Hz instead
of 20. Two ladders that move alike, because they are the same ballistics.
Guard: MeterScaleTests pins the attack/decay behaviour alongside peak-hold.
Creator: "why is there no meter for when trax is playing?"
Routing answer: TRAX rides the desktop loopback, so it already moved the GAME ladder — there was no
separate TRAX signal in the mix. But that ladder cannot answer the question a deaf creator actually
has: "is the music producing sound at all?" The play glyph cannot either — an open file with a dead
decoder still reports Playing.
So the player now measures its own output: \`MusicPlayer\` wraps the volume stage in an NAudio
\`MeteringSampleProvider\` and exposes \`Level\`; \`ITraxPlayer.Level\` keeps the fake honest. The VM maps
it through the same display scale (\`TraxMeterFraction\`), zeroed when not playing, and the TRAX bay
carries a 24-segment ladder above its fader.
This reverses my earlier "no ladder, nothing honest to show" — the honest thing arrived with a real
measurement. TraxBayTests flipped accordingly (it now asserts the ladder AND its source).
Unit 7. The bay shows the track name (left-click toggles playback, right-click opens the picker —
the label stays the control), a play/pause button, the duck badge, and a dB level.
No ladder here, deliberately: nothing measures the music bed, and a decorative ladder would break
the measured-not-painted rule. A test asserts the bay has no SegmentMeter.
The level is real: `ITraxPlayer.UserGain` is a new creator gain multiplied onto the fixed design
volume, separate from `LocalGain` (which follows the desktop mute). The VM's `TraxVolumeDb` is the
same dB scale as the other faders, so unity means the bed's design level.
1. Error text shows in red inside the desktop audio meter bar (scrollable)
when TRAX load or playback fails — user gets feedback, not just a
silent red dot.
2. LoadTrax no longer nulls _music on error — the track path is retained
so the user sees what failed and can retry.
3. OnTraxPlaybackEnded now receives the NAudio exception and surfaces it.
4. TRAX dot is green (playing) or gray (idle/no track) — no more yellow
or red states.
207 tests, 0 warnings.
gramps