CODEWITHSUNDEEP
pythonaudiolibrosa
Literate Goggles
Literate Goggles

Reputation: 368

Why does multiplying audio signal amplitude by any coefficient doesn't change it?

Suppose you have the following float32 audio representation loaded from any wav file using the librosa package:

import librosa

wav_x_path = "any_wav_filepath.wav"
wav_source, _ = librosa.load(wav_x_path, sr=16000)

If you then will try to play this audio using, for example, a jupyter notebook, the following snippets sounds in the same way:

from IPython.display import display, Audio

display(Audio(wav_source * 2, rate=sampling_rate))
display(Audio(wav_source * 200, rate=sampling_rate))
display(Audio(wav_source / 200, rate=sampling_rate))

Why does it happen that changing audio aptitude (if I correctly understand what wav_source contains audio amplitude), doesn't affect how the audio sounds?

Upvotes: 1

Views: 479

Answers (1)

Jon Nordby
Jon Nordby

Reputation: 6259

As per the documentation of IPython.display.Audio there is an argument normalize which decides whether to apply automatic scaling of the volume. The default is normalize=True, which is why different amplitude scales is played back at the same level.

Use display(Audio(wav_source * 2, rate=sampling_rate, normalize=False)) and you should be able to hear the difference.

Upvotes: 1

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