Answer :
Final answer:
The required sample rate for audio recording is based on the Nyquist rate and is typically 44.1kHz for CDs and 48kHz for DVDs. Bit depth can be reduced to lower file sizes without greatly affecting sound quality for most music, as exemplified by iTunes allowing users to select lower bit rates.
Explanation:
The sample rate required for recording audio relates to the Nyquist rate, which is the minimum sample rate needed to accurately record a given frequency. According to the sampling theorem, an audio signal with bandwidth B can be perfectly captured by sampling at a rate of more than 2B samples per second. For human-audible frequencies, which typically do not exceed 15,000 Hz, audio must be sampled at above 40kHz, with common standards being 44.1kHz for CD recordings and 48kHz for DVD recordings.
Bit depth, which determines the number of voltage steps recorded, can be adjusted to reduce file size without significantly impacting the audio quality for most listeners. For example, software like iTunes allows users to choose lower bit rates such as 64 kbps from a higher rate like 320 kbps, thus reducing the file size significantly while maintaining acceptable sound quality for many types of music.
