# Guitar — mechanical fretting 01

**New and unapproved; not a finished realistic guitar or saxophone.**

Same 19.2-second Giant Steps solo chorus, 90 written notes and exact backing.
A retains the calibrated earlier modal guitar. B uses a new mechanical tension
string, driven fret contacts, reciprocal bridge modes and finite-width relative
velocity pickup. Its 32 connected arrivals do not sweep oscillator frequencies:
finger contacts change the speaking termination while string/bridge state runs.

This changes the instrument source and its physical articulations, not just one
parameter. The finger model is a bilateral spring/dashpot termination, not full
unilateral finger/fretboard collision. Dimensions, body modes and trajectories
are provisional, not measured from a named real guitar. Picked gestures still
initialize independent plucks; persistent six-string state is not implemented.

The original amp/cabinet/EQ/room/echo and rhythm stay fixed. One pickup-output
RMS calibration is applied before the amp, and one post-amp gain matches guitar
loudness. Any shared safety gain is reported. No samples, paid APIs, new melody,
bus compressor or full-song replacement. Earlier pages/audio/source stay intact.

`probe` demonstrates three held notes, an ascending contact, a pulling release,
and two ascending contacts through this same source/amp. It uses one shared gain,
not individual note normalization. `verification.json` reports independent
mechanical solves, passivity, 36 held-pitch fixtures, four gesture refinements
and signed mechanical-work checks. These are not proof of convincing sound.

The complete local recipe is `music4/studies/guitar-fretting-05/README.md`.
The model source, modelling references and full numerical reports are retained
on this page alongside WAV/MP3 comparisons. All audio uses manual playback.