PROJECT 05 // PHYSICAL INSTRUMENT & AUDIO MODELING

ArcoAura

An engineering prototype being built to treat a guitar as what it actually is -- one continuous physical conversation from string motion to speaker cone -- connecting pickup construction, electrical circuits, amplifiers, cabinets, and microphones into a single inspectable signal path.

STATUS ActivePROGRESS 68%

EXPLORE THE PHYSICAL SIGNAL PATH

08 SECTIONS

ArcoAura is a scientific instrument and audio design environment. It connects playable string motion, physical pickup construction, electrical simulation, amplification, and acoustic capture without hiding where one model ends and the next begins.

S01 // Harmonic model active

String Simulation

A bounded real-time harmonic source currently turns MIDI pitch, excitation, decay, release, and simple harmonic content into the signal a pickup model observes.

OPEN SECTION →S02 // Equivalent circuit active

Pickup Simulation

A first pickup model combines position-sensitive harmonic observation with an equivalent RLC loading model; calibrated magnetic transduction remains future work.

OPEN SECTION →S03 // Coil solver active

Pickup Construction

Bobbin geometry, wire gauge, turns, magnet material, winding depth, DCR, inductance, topology, and fit become one buildable specification.

OPEN SECTION →S04 // MNA engine active

Circuit Simulation

Implemented component models compile into a stateful modified nodal analysis network, with nonlinear behavior solved iteratively and broader validation still underway.

OPEN SECTION →S05 // Modular chain active

Instrument Signal Path

String motion becomes raw pickup DI before pedals, amplifier, speaker, microphone, and room stages are composed into an inspectable rig.

OPEN SECTION →S06 // Deterministic IR active

Speaker, Cabinet & Microphone

A deterministic engineering approximation derives a repeatable response and impulse response from driver, enclosure, microphone, and room parameters.

OPEN SECTION →S07 // Manifest model active

Modules & Exports

Physical construction, processing model, ports, parameters, assets, and export targets remain together as reusable ArcoAura modules.

OPEN SECTION →S08 // Signal chain active

Real-Time Engine & Analysis

Block processing, persistent model state, bounded voices, frequency analysis, deterministic tests, and stable exports keep physical simulation playable and inspectable.

OPEN SECTION →

The instrument is the signal path

ArcoAura treats a guitar or related instrument as a connected physical system. String motion becomes pickup voltage, pickup construction shapes resonance, controls and circuits load the signal, amplifiers introduce nonlinear behavior, and speakers, cabinets, microphones, and rooms complete the result.

The goal is not a collection of disconnected effect screens. A physical choice should remain visible in the sound it produces, and every approximation should say what it represents.

Scientific designer as the target

Pickup construction and pickup placement are separate because they are separate physical questions. A winding can be designed from bobbin geometry, wire gauge, turn count, resistance, inductance, capacitance, and magnetic assumptions, then placed at a measured position and height on an instrument.

The declared physical model is the source of truth for the prototype. Calling the finished environment a scientific instrument will require calibration, uncertainty reporting, repeatable measurements, and comparison against physical instruments. Those validation steps remain future work.

ArcoBASIC as the shared language

ArcoBASIC communicates the implementation with executable code that reads at the level of a clear engineering explanation. The examples throughout this project are commented so a person can follow the physics, the assumptions, and the signal flow without translating ceremonial complexity first.

This is part of the Arcology philosophy. Technical depth should invite people inward. It should not demand that they prove endurance before they can understand an idea.

Honest fidelity

The current string source is an early harmonic model with bounded real-time voices. Pickup loading and the circuit solver are active foundations. Coil construction is empirically derived and reports disagreement. Speaker and cabinet response is deterministic and parameter-derived.

Planned fidelity work includes dispersive digital waveguides or modal strings, richer boundary interactions, calibrated magnetic coupling, and measured comparison against physical instruments. The project distinguishes implemented behavior from future models instead of using realism as a vague label.

Model the cause, not the effect you want

It would be faster to fake a plausible-sounding tone with a filter chain than to simulate string motion, magnetic coupling, and speaker cone behavior separately. ArcoAura deliberately takes the slower path, and that choice is the part worth carrying into an unrelated project.

Model the physical or logical cause of a behavior instead of curve-fitting its typical output. A pickup construction model built from bobbin geometry, wire gauge, and turn count stays correct when someone changes one of those inputs; a tone preset tuned to sound right does not.
Keep every stage of a signal path, or any multi-stage system, separately inspectable. String motion, pickup voltage, circuit loading, amplifier nonlinearity, and cabinet response are five distinct, checkable claims here, not one opaque black box a listener has to trust all at once.
State exactly what each approximation stands in for and what it does not yet capture, the way coil construction here is named as empirically derived with reported disagreement rather than presented as settled physics. A labeled approximation can be improved later; an unlabeled one just becomes a silent limit nobody remembers to revisit.

LEARNING LAYER

Key terms, in plain language

You do not need a systems background to follow the work. These are the specialized terms used on this page.

Physical modeling: Producing sound by simulating the behavior that causes it, such as a vibrating string or electrical circuit, instead of replaying a recording of the finished result.
Partial: One sinusoidal component of a complex vibration. A harmonic is a partial whose frequency is a whole-number multiple of the fundamental frequency.
Pickup aperture: The short region of a string that a pickup observes rather than one infinitely small point. Its width changes how strongly different harmonics contribute.
MNAModified Nodal Analysis: A circuit-solving method that builds equations for node voltages and selected branch currents, then solves the resulting matrix at each time step.
Signal chain: The ordered path a signal follows through a system. In ArcoAura it begins with string motion and can continue through pickup, pedals, amplifier, speaker, microphone, and room.