Speaker, Cabinet & Microphone

The cabinet is part of the instrument

ArcoAura models the speaker driver, enclosure, and capture chain separately. Driver parameters include resistance, inductance, force factor, moving mass, compliance, mechanical and electrical Q, free-air resonance, equivalent volume, sensitivity, breakup, and high-frequency rolloff.

The cabinet contributes topology, internal volume, baffle dimensions, depth, tuning, leakage, absorption, and open-back ratio. The microphone contributes pattern, distance, off-axis angle, dust-cap offset, and room mix.

Derived response

Driver resonance and equivalent volume interact with cabinet volume
Mechanical and electrical Q combine into total damping
Open-back, sealed, vented, transmission-line, and horn behavior alter resonance and Q
Baffle width determines the approximate baffle-step region
Cone breakup creates a controlled high-frequency resonance
Microphone angle lowers and reshapes high-frequency capture
Distance and room mix add a delayed decaying contribution

Cabinet volume changes system resonance

This ArcoBASIC example communicates the current Thiele/Small-style derivation. It is deterministic: the same physical parameters produce the same response and therefore the same generated impulse response.

ArcoBASICArcoBASIC communication example: derive sealed-box resonance and Q

' Derive the primary resonance of a driver in an enclosure.
FUNCTION CabinetResponse(freeAirHz, vasLitres, boxLitres, mechanicalQ, electricalQ)
    totalQ = 1 / ((1 / mechanicalQ) + (1 / electricalQ))
    boxRatio = vasLitres / boxLitres
    scale = SQRT(1 + boxRatio)

    RETURN {
        "SystemResonanceHz": freeAirHz * scale,
        "SystemQ": totalQ * scale,
        "LowCutHz": MAX(18, freeAirHz * scale * 0.38)
    }
END FUNCTION

response = CabinetResponse(95, 58, 72, 7, 0.46)
PRINT response.SystemResonanceHz
PRINT response.SystemQ

Impulse response as a reproducible approximation

The current generator builds an impulse, applies derived low cutoff, system resonance, cone-breakup emphasis, and high-frequency rolloff, then adds a distance-dependent room contribution. The waveform can be serialized as an impulse response, but it has not yet been validated as a prediction of a particular physical cabinet.

Future fidelity can add measured comparison, nonlinear excursion, thermal compression, measured materials, finite-element breakup, and more advanced room propagation without changing the driver-cabinet-microphone boundary.

A deterministic approximation earns its own honesty

Thiele/Small parameters, box ratios, and cone-breakup emphasis are specific to loudspeaker enclosures. Nobody outside audio engineering needs that equation. What is worth keeping is how a deterministic approximation was allowed to be useful without being allowed to be mistaken for validated.

The same discipline shows up wherever a simulation or estimate has to be useful now and honest about its own limits: a financial model that is deterministic and reproducible long before it is validated against real outcomes, a load-testing harness that reports a repeatable estimate rather than dressing up a guess as a measurement. Determinism and accuracy are different claims, and conflating them is how simulations quietly become lies.

Make the approximation reproducible before making it accurate. CabinetResponse always returns the same resonance and Q for the same physical parameters, which is what makes it testable and debuggable even before it has been checked against a real cabinet.
State plainly what a result is not. Calling the generated impulse response "not yet validated as a prediction of a particular physical cabinet" prevents a deterministic-looking output from being mistaken for a measured one.
Keep the ownership boundary, driver, enclosure, microphone, room, fixed while fidelity work happens inside it. Nonlinear excursion, thermal compression, and finite-element breakup can all be added later without redefining what a driver or a cabinet means.
Derive a response from named physical causes, resonance, Q, baffle-step, breakup, instead of tuning an equalizer curve to sound right, so a wrong result traces to a wrong input rather than to an opaque fudge factor.

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.

Thiele/Small parameters: A set of measured electrical and mechanical speaker-driver values used to predict how the driver interacts with an enclosure.
Impulse response: A recording or generated description of how a system responds to a very short impulse. Convolution can apply that response to other audio.
Q factorQuality factor: A measure of how narrow and pronounced a resonance is. Higher Q produces a sharper peak; lower Q produces broader, more heavily damped behavior.
Resonant frequency: A frequency where a system naturally responds more strongly. In a passive pickup, inductance and total capacitance help set this peak.