Macintosh sound files

A way for storing a Sound object on disk.

File format

The double-clickable sound file of the Macintosh (8 bits per sample). Cannot be ported to other machines, because the sound is in the resource fork.

Reading

With Read from file....

To read a Sound from a Macintosh sound file on disk, use Read from file... (Macintosh only).

The 8-bit sample values are divided by 128 so that the amplitude of the resulting Sound is between –1.0 and +1.0.

The resulting Sound will appear in the list of objects; its name will be equal to the file name, without extension.

Saving

With Save as Mac sound file.... Praat asks you for a file name. After you click OK, 0.5 is added to the samples of the Sound, they are multiplied by 128 and quantized between 0 and 255; the result is written to the file in 8-bit linear Macintosh sound-file format.

To avoid clipping, keep the absolute amplitude below 1.000. If the maximum sound pressure level is 91 dB (top = 127), the quantization threshold for a sine wave is (top = 1/2) 43 dB.


© ppgb, January 31, 2011