This document introduces digital audio by explaining the difference between analog and digital signals. It describes key variables that affect audio sampling including sampling rate, bit depth, and number of channels. Higher sampling rates, bit depths, and more channels captured result in higher quality audio files but also larger file sizes. The optimal balance of these variables must be determined based on the intended use and quality needed for the audio.

1. Introduction to Digital Audio

2. Objectives Explain the difference between analog and digital signals Identify audio sampling standards Describe audio sampling variables Determine how variables affect file size and quality

3. Analog vs. Digital Signals Analog – A continuously recorded sine wave signal usually recorded on a magnetic medium

4. Analog vs. Digital Signals Digital – A signal that samples specified portions of a signal resulting in discrete digital information (i.e. bits of data) “ Sampled” discrete data

5. Audio Sampling Variables Three main criteria: How many samples? OR “sampling rate” How much data per sample? OR “bit depth” How many channels sampled?

6. How Many Samples? Audio “Sampling Rates” Digital Video CD Quality Stereo FM Radio AM Radio Telephone

7. How Many Samples? Audio “Sampling Rates” Digital Video 48,000 per sec 32,000 per sec

8. How Many Samples? Audio “Sampling Rates” CD Quality 44,100 per sec Left & Right Channels Combined

9. Other Sample Rates Typical Sample Rates: Sample Rate Less 8000 Quality Telephone 11000 AM Radio 16000 FM Radio 22050 per Stereo

10. How Much Data per Sample? Common Sampling “ Bit Depth” 8 bits of data per sample 16 bits of data per sample

11. How Many Channels Sampled? Number of Channels Stereo (2 channels) Mono (1 channel) Multiple tracks

12. Audio Sampling Variables File Size Digital Audio Quality

13. Audio Sampling Variables Balance Sample Rate Bit Depth Number of Channels Record Settings Sound Quality File Size

14. Audio Record Rate More Audio Samples Larger Audio Files

15. Audio File Size File size is determined by a combination of: Bit Depth Sample Rate No of Channels

16. Audio File Size File size is determined by a combination of: Length in Minutes Bit Depth Sample Rate No of Channels

17. Audio File Size Variables of concern: 8 bit or 16 bit Various Sample Rates Stereo or Mono Length in Minutes