Each of the N bars stands for one frequency band spread evenly around the circle, low frequencies at 0° sweeping up to the highest band near 360°. Since no microphone or audio file is attached, each band's amplitude comes from a small synthetic model instead of a real FFT: a slow "envelope" oscillator (standing in for a beat/tempo track) is multiplied by a per-band oscillator whose own frequency rises with the band index, exactly the way bass bands genuinely swing slower and wider than treble bands on a real spectrum analyzer.
Sensitivity scales every band's amplitude before it's drawn — the same knob a real equalizer's gain stage would be. Decay smoothing blends each new sample with the bar's previous height (an exponential moving average) so bars fall smoothly instead of snapping, matching the "ballistics" a hardware VU meter or DAW spectrum display uses. Peak hold keeps a small marker at each bar's highest recent point before it slowly drifts down.
- Preset — changes the underlying envelope/tempo shape: a slow deep pulse, a fast drop-style build, a flat ambient wash, or a mid-band-heavy voice pattern.
- Band count — how many bars divide the circle.
- Sensitivity — output gain applied to every band.
- Decay smoothing — how much a bar resists falling instantly (0% = instant snap, high % = slow float-down).
This mirrors the 3D circular-bar version of this simulation but renders the same per-band model as a flat 2D canvas ring instead of extruded 3D boxes.