VCV Rack plugin Free
Fourier.
See what you hear.
Fourier compares up to four spectra; Spectre shows how frequency content changes over time. Two visual analysis modules for VCV Rack.
Get it in VCV Rack
- Complementary views
- 02
- Spectrum inputs
- 04
- For VCV Rack 2
- Free
Visual analysis
Compare the signal.
Check an oscillator’s harmonics, compare a filter’s input and output, or inspect the frequency content of a transient. Fourier puts those views in the rack, beside the modules producing the sound.
Use Fourier to compare up to four signals at once. Switch to Spectre when the question is how a sound changes over time. These are visual analysis tools: patch them beside your audio path, without changing what you hear.
FFT settings.
Choose FFT lengths from 128 to 16,384 samples. Adjust the hop size, window, and smoothing for the signal you want to inspect.
Spectrogram.
Follow changes in frequency content over time. Freeze the display to inspect frequency and magnitude, or change the palette of the captured frame.
Display controls.
Set frequency bounds, linear or logarithmic axes, and per-input gain. Factory presets offer starting points for bass, harmonics, transients, and tonal balance.
An idea to patch
Compare a filter’s input and output.
A simple patch for seeing how cutoff and resonance change a signal.
Split the signal.
Send an oscillator to Fourier’s first input and the filtered version to its second. Keep your usual audio output connected.
Move the cutoff.
Compare the two spectra as you sweep the filter. Raise resonance to see a peak emerge around the cutoff.
Freeze a moment.
Send the filtered signal to Spectre. Freeze the display to inspect a moment, then adjust the palette or intensity range.
Behind the instrument
How can an FFT share the audio thread?
Scheduling FFT-Based Spectral Analysis in the Audio Processing Loop
CoopFFT spreads spectral analysis across successive audio-sample calls, without a separate analysis thread. The paper explores the tradeoff between smaller processing bursts, total work, and the delay before a spectrum is ready.
Resources
Manuals and source.
Documentation and source code for the plugin.