This browser cannot draw the 3D engine. The sound and the data panel still work.
Every engine speaks
What you are hearing
Everything arriving on time
Critical Sound Design Studio, CEPT University
Every engine speaks
An engine is always describing itself. Every firing pulse, tick, hiss and knock is information about metal, timing and combustion, arriving faster than any gauge.
This instrument puts that language back in your ears. Choose a machine, turn one dial, and listen to a healthy engine change. The engine turns in front of you, so you can see what you are hearing.
Aaryan Rathore Tutor Anirban Ghosh (Baan G), TA Kirti Sharma
Choose a machine
About
Listening as a way of knowing a machine
Before diagnostics arrived on screens, a mechanic put a screwdriver to a valve cover and heard the fault. This project asks what that skill was, where it went, and whether an interface can hand some of it back.
Why sound
Sound is the fastest description a machine gives of itself. A combustion engine repeats a cycle up to two hundred times a second, and every event in that cycle leaves an acoustic trace: the pulse of combustion, the click of a valve closing, the slap of a worn bearing, the hiss of air entering where it should not. A gauge averages all of this into a number. The ear keeps the timing.
That timing is where the meaning lives. A misfire is not a pitch, it is a missing beat once every two crankshaft revolutions. A valve tick runs at half crank speed because the camshaft turns half as fast. A rod knock lands once per revolution and gets louder the instant load changes. A belt squeal ignores the engine's rhythm entirely. Learn the rhythm and the fault names itself, which is exactly what experienced mechanics do without being able to explain how.
So the design question here is not how to make an engine sound realistic. It is how to make a fault legible: to pair each sound with the moving part that causes it, the rhythm it follows, and the reading that would confirm it.
The inquiry
Where the project started. Four questions, each of which changed the interface: who listens, what in the sound carries meaning, how that skill was absorbed by sensors, and what an instrument can teach in the thirty seconds a visitor gives it.
Mapping a fault to a sound
The working map. Faults separate cleanly once rhythm is treated as the primary axis and pitch as the second. Two faults can share a frequency band and still be unmistakable, because one arrives on the beat and the other ignores it. The interface is built on this map: the dial changes the fault, the engine clock shows the rhythm, the spectrum shows the band.
Three versions of the interface
The first version was correct and boring: a dial and a list. The second buried the sound under data. The third moves the engine to the centre and hides everything else behind one button, because in an exhibition attention is the scarce material, not information.
Decisions worth defending
One dial, and what it honestly means. A single knob implies that faults sit on a line from healthy to broken. They do not: a belt squeal is not halfway between health and a misfire. So the dial runs along accumulated wear, with faults appearing in a plausible order, and a second mode isolates one fault and makes the dial its severity. That sequence is illustrative, not a prediction of how a particular engine fails.
The instrument does not diagnose. The dial sets the fault and the interface shows it. Recognising a fault from audio is a different problem, one that needs labelled recordings and a trained classifier. Saying this plainly matters, because an interface that looks like a diagnosis invites people to trust it like one.
The sound is generated, not sampled. Every engine here is built from a physical description: cylinder count, firing order, bore, pipe length, and the resonances of the block, with fault layers scheduled against crank angle. That is what makes the dial continuous, and it also means these are archetypes of engine families rather than portraits of the specific vehicles named in the menu.
The animation is slowed. An idling engine turns about thirteen times a second. The 3D view runs at roughly a twelfth of that, the way a timing light freezes motion, so a visitor can see the piston that did not fire.
Sound cannot be the only channel. A piece about listening excludes anyone who cannot hear it, so the engine, the cycle clock and the spectrum each carry the whole message on their own.
Credits
Studio
Critical Sound Design
Institution
CEPT University
Tutor
Anirban Ghosh (Baan G)
Teaching assistant
Kirti Sharma
Student
Aaryan Rathore
Technology
Web Audio APIReal-time synthesis in the browser. Combustion pulses are scheduled against crank angle, then passed through a saturator, an exhaust delay line and a muffler filter. Fault layers are separate voices: tuned resonators for knock and ticks, filtered noise for leaks, oscillators for belt and turbo tones.
three.js (r128)The engine is generated procedurally from each machine's parameters: cylinders, bank angle, bore, firing order. Pistons, rods and crank throws are driven by slider-crank geometry, and combustion is a point light plus an additive sprite inside each chamber.
Canvas 2DThe cycle clock and the scrolling spectrogram, drawn per frame. The spectrogram reads a live analyser node, so what it shows is measured from the audio rather than modelled.
Plain HTML and CSSNo framework. The knobs are layered CSS gradients and masks rather than images, so they scale to any screen and stay crisp on a projector.
One static fileThe whole instrument is a single page with no build step, deployed on Vercel, which also means it runs from a USB stick if a gallery has no network.
AccessibilityBoth knobs are keyboard operable sliders with spoken values, the dial has text alternatives for every state, and reduced-motion settings slow the animation instead of stopping it.
Reading that shaped it
Stefan Krebs, Dial Gauge versus Senses 1 to 0: German Auto Mechanics and the Introduction of New Diagnostic Equipment, Technology and Culture, 2014. On how instruments displaced diagnostic listening, and what mechanics lost with it.
Stefan Krebs, Sobbing, Whining, Rumbling: Listening to Automobiles as Social Practice. The salesman whose mysterious slapping noise turned out to be a road lined with poplars.
Karin Bijsterveld, Sonic Skills, and Sound and Safe: A History of Listening Behind the Wheel. Listening as a research method across science, medicine and engineering.
Gaver, Smith and O'Shea, Effective Sounds in Complex Systems: The ARKola Simulation, CHI 1991. The ancestor of every interface where machines tell you their state by sound.
Baldan, Lachambre, Delle Monache and Boussard, Physically Informed Car Engine Sound Synthesis, IEEE, 2015. The procedural engine model this build leans on.
Work on engine fault detection from sound and vibration, including fine-grained fault sound event detection with professional inspectors, which supplied the fault taxonomy used here.