Compressor 4 - Sound Sample Rates

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Sound Sample Rates

Digitized sound consists of sound samples captured at different frequency rates. The
more sound samples per second, the higher the sound quality. For example, audio CDs
use a 44.1 kHz sample rate, DVDs sample at 48 kHz, and telephone networks sample
voices at 8 kHz. The sample rate you choose depends on the nature of the sound. Music
requires a higher sample rate than voice, because music contains a wider range of
frequencies. Spoken voice has a more limited range of frequencies, so you can choose a
lower sample rate and still maintain acceptable audio quality. In most cases, you should
choose the highest sample rate available.

Reducing the sample rate can shrink a media file by as much as 5:1. The audio quality
will be affected, but not as much as it would be if you used 8-bit sampling. The following
table shows common sample rates and the audio device quality to expect at each rate:

Audio device quality

Sample rate


48 kHz


44 kHz

FM radio

22 kHz


8 kHz


Chapter 21

Creating QuickTime Movie Output Files