Conclusions
Sampling rate and sample resolution combine to determine the overall
quality or fidelity of digitized sound. For digitized speech, sampling
rates and sample resolutions typically range from low (telephone)
quality values of 8000 Hz sampling rate with 8-bit samples (i.e., 4000
Hz Bandwidth and 48 dB dynamic range) to CD quality at a 44100 Hz
sampling rate with 16-bit samples (22050 Hz Bandwidth and 96 dB
dynamic range). Historically, much of the speech research using
digital speech signals has been done with sampling rates of 10,000 to
12,000 Hz and 12-bit sample resolution. However, present day speech
research typically involves use of sampling rates in the 16,000 to
22,050 range with sample resolutions of 16-bits. This change has taken
place mostly for two reasons: hardware to sample sound at higher
frequencies and bit resolutions has become much more affordable; and,
even more crucially, storage space has become significantly less
expensive. This latter factor is perhaps the most important since
speech sampled at 22050 Hz and 16-bit resolution will require more
than five times more space to store than would speech sampled at 8000
Hz and 8-bit resolution.