Sub Pressure Forge turns one enormous speaker into a playable sub-bass workbench. Six service leads pull synthesis parameters into physical modules around the cone: body frequency, pitch fall, tail length, harmonic iron, drive crush, and attack mallet. The orange striker in the dust cap auditions the current recipe through Web Audio, while Cellar, Concrete, and Airlock provide useful starting points.
Shape a tight kick, a long pressure swell, or a clipped industrial thud. Every control updates its numerical state and the cone response. The recipe stays in local storage between visits. Stamp WAV exports a deterministic 48 kHz mono one-shot, and Recipe writes the exact parameter state to JSON for later reconstruction.
Three interacting systems run the forge:
- Deterministic synthesis. A fixed 48 kHz renderer combines an exponential pitch fall, amplitude decay, harmonics, drive, and a short attack transient. The browser audition and exported WAV use the same recipe, so the file reflects the sound shaped on the speaker.
- Physical speaker interface. A responsive SVG apparatus fills the viewport with a cropped rubber cone, aluminum basket, animated pressure contour, radial wired controls, keyboard performance, and three stateful presets. The mechanism remains visible on desktop and mobile instead of collapsing into a generic control dashboard.
- Production persistence and export. Local storage retains the current recipe without an account. WAV export emits verified RIFF bytes, while JSON export records the recipe and 48 kHz sample rate in a portable text artifact.
Vue 3 keeps parameter state, presets, persistence, and the SVG apparatus synchronized without a custom state layer. SVG handles the speaker geometry and scales cleanly across the 1600×900 proof frame and a 375-pixel mobile viewport. Web Audio gives immediate local audition, while an offline sample renderer provides deterministic export. That split costs a small amount of duplicated signal plumbing, but it prevents device scheduling from changing the rendered file.
The instrument runs entirely in the browser and collects no user data. Playwright checks desktop and mobile containment, 44-pixel touch targets, keyboard focus, preset mutation, striker response, WAV RIFF bytes, JSON state, and zero console errors.