Tutorial - Understanding spectrograms
From Audacity Development Manual
Under construction
Contents
Introduction
Example sounds
In this tutorial, several example sounds are shown repeatedly with variations of settings. Follow these instructions to recreate those sounds.
- Silence: Use the Silence generator to create silence of any given duration.
- Impulses: To create the briefest possible click sound or "impulse," enable the Draw Tool, then zoom the view of a track until individual samples are visible. Hold CTRL and drag one sample upward or downward as far as possible.
- Chromatic Scale: Generate one second of silence. Select the silence. Use the Nyquist_Prompt effect, and copy and paste the following code into the text entry. Click . The result is an ascending chromatic scale of pure tones separated by rests. The notes begin at middle C and continue for four octaves. Each is one-half second long with a tapering envelope.
(let ((scale (s-rest 0))
(env (hzosc (/ (get-duration 1)))))
(dotimes (ii 49)
(setq scale
(sum scale
(at ii
(seq
(prod
(cue env)
(cue env)
(cue (osc (+ 60 ii) 0.5)))
(s-rest 0.5))))))
(prod 0.99 scale))
- Pluck: The Pluck generator simulates a plucked string.
- Chirp: The Chirp generator creates a continuously varying tone, rising or falling linearly or exponentially in frequency.
Default Preferences
Unless otherwise specified, all images use default values for Spectrogram Preferences. These are:
- WindowSize: 256
- WindowType: Hanning
- Zero Padding Factor: 1
- Minimum Frequency: 0 Hz
- Maximum Frequency: 8000 Hz
- Gain: 20 dB
- Range: 80 dB
- Frequency gain: 0 dB/decade
- Grayscale: off