Sample Sound Frequencies Node

The Sample Sound Frequencies node retrieves the amplitude of a frequency range from a sound data-block at a given point in time.

This can be used to drive animations, procedural effects, or geometry based on the intensity of specific frequency bands in an audio file.

Inputs

Sound

The sound data-block to sample.

Time

The time, in seconds, at which to sample the sound.

All Channels

Mix all audio channels together before sampling.

For example, a stereo sound is converted to a single mono signal.

Channel

The audio channel to sample when All Channels is disabled.

Low

The lower bound of the sampled frequency range, in Hertz.

High

The upper bound of the sampled frequency range, in Hertz.

FFT

Settings that control the Fourier transform used for frequency analysis.

FFT Size

The number of audio samples processed in each discrete Fourier transform.

Higher values provide better frequency resolution but lower time resolution. Lower values provide better time resolution but lower frequency resolution.

128:

Very high time resolution with coarse frequency resolution.

256:

High time resolution with coarse frequency resolution.

512:

Balanced toward time resolution.

1024:

Moderate frequency and time resolution.

2048:

Good balance between frequency and time resolution.

4096:

Increased frequency resolution with reduced time resolution.

8192:

High frequency resolution for detailed spectral analysis.

16384:

Very high frequency resolution with low time resolution.

32768:

Maximum frequency resolution with the lowest time resolution.

Window Function

Applies a weighting function to the analyzed samples before performing the Fourier transform. This reduces discontinuities at the edges of the sample window, helping to reduce spectral artifacts.

Hann:

General-purpose window with good frequency analysis characteristics.

Hamming:

Similar to Hann with slightly different side-lobe behavior.

Blackman:

Provides stronger suppression of spectral leakage at the cost of wider frequency peaks.

Rectangular:

No windowing is applied.

Outputs

Amplitude

The summed amplitude of all frequencies within the specified frequency range.