# Guitar — spatial pickup comparison

Experimental, unapproved and sample-library-free. A plays the preserved
electrically loaded pickup from the previous comparison. B uses the same full
248-note performance with the sensing aperture moved from 10.5 to 16.2 cm
from the bridge. The old files, source, notes and backing remain intact.

This is a spatial readout of the existing mechanical velocity field, not an EQ
preset. The 12 mm aperture, original mesh, mass/tension, contacts, six-string
state, bridge, electrical circuit, Music II amp/cabinet/EQ, room and echo are
unchanged. Every complete-performance mechanical work/pick sample matches the
previous render exactly. Isolated tests also compare final mechanical states.

[Paiva, Pakarinen and Välimäki (2012), author-uploaded paper](https://www.researchgate.net/publication/234034228_Acoustics_and_Modeling_of_Pickups)
explains pickup position, sensitivity width and fret-dependent cancellations.
Its typical 16.2 cm neck location on a 64.8 cm scale motivates this illustrative
geometry. This is not a measured named guitar, Slash rig or humbucker model.

One constant gain matches B's amplifier-input RMS to A. One constant post-amp
gain matches the full guitar's integrated loudness. No per-note normalization,
new score, bus dynamics or backing changes are used. A directly references the
unchanged earlier recording; it is not synthesized again for this page.

Finite-aperture integration is independently checked with quadrature,
standing-wave responses, spatial refinement and exact mechanical-state
counterfactuals. All written-note pitch windows are checked after the electrical
stage. These are technical checks, not proof of convincing or improved tone.

Full nonlinear magnetic flux, distributed winding capacitance, electromagnetic
feedback, bending stiffness, polarization coupling, unilateral hand contact and
measured hardware remain unfinished. No audio was played by the agent, no paid
API was called, and the page uses manual players without preload or autoplay.

The local build recipe is `music4/studies/guitar-pickup-position-09`: run
`python3 verify.py`, `python3 render.py`, `node amplify.mjs`, `python3 export.py`.
Sources are published here; dependencies are the preceding frozen engine,
geometry, electrical circuit, score/rhythm and Music II DSP, plus
NumPy/SciPy/Numba/SoundFile, Node.js and ffmpeg.