Purpose

Spectrum Publish takes stereo audio and emits a spectrum ring. It is a lightweight way to expose the current frequency content of a signal for analysis and spectrum-aware downstream nodes, computing one windowed FFT frame from each engine block.

Use

Wire stereo audio into in and route out to any node that reads a spectrum ring. Reach for this when you want frequency content published from a point in the chain without managing overlapped framing. For a transparent analyze-and-resynthesize round trip back to audio, use Spectrum STFT into Spectrum ISTFT instead.

Inputs and outputs

• Input 0: in accepts stereo PCM. It is required.
• Output 0: out emits a stereo spectrum ring.

Controls

• Windowsize: FFT window in samples: 512, 1024, 2048, or 4096. Larger windows give finer frequency detail.
• Hopsize: window advance as a fraction of the window: quarter, half, full, or eighth.
• Window: window shape: hann, blackman, or rect.

Notes

• Input must be stereo.
• A block shorter than the selected window is zero-padded for the frame.
• For full spectral processing and resynthesis, pair Spectrum STFT with Spectrum ISTFT rather than using this publisher.

Ports

Inputs

• in row required
  audio_pcm_f32_stereo_v1

Outputs

• out row
  spectrum_stereo_v1

Parameters

Windowsize (Windowsize) Menu op('spectrum_publish').par.Windowsize

Default:

1024

Options:

512, 1024, 2048, 4096

Hopsize (Hopsize) Menu op('spectrum_publish').par.Hopsize

Default:

quarter

Options:

quarter, half, full, eighth

Window (Window) Menu op('spectrum_publish').par.Window

Default:

hann

Options:

hann, blackman, rect