Simulates an FFT-style audio frequency spectrum — the kind produced by a Web Audio AnalyserNode — without any real audio input. A BPM-driven kick envelope, layered sine harmonics and smoothed 1D value-noise are combined per frequency band to fake bass, mids and jittery highs. The result is mapped onto a circular array of bars whose height, color and glow react in real time, alongside a bass-reactive particle ring and a pulsing center sphere that stand in for a subwoofer cone.