1. Digital Sound Actual representation of sound Stored in form of thousands of individual numbers (called samples) Not device dependent Stored in bits

2. Advantages of Digital Sound Consistent playback quality Wider selection of application software and system support for digital audio No demand for music theory and musical scores

3. Disadvantages of Digital Sound Does not allow for the manipulation of all details of composition Huge files Significant processor overhead

4. Sound Quality Capture at highest possible quality Determine by capabilities of target delivery platform

5. Sampling Rate number of samples per second, measured in kilohertz (kHz) –higher sampling rate, higher sound quality

6. Sampling Size size in bits used to quantify the signal types of sample size – 8-bit –16-bit –larger sample size, better the data describes recorded sound larger sample size, more "steps”are represented within dynamic range of sound

7. Stereo Vs. Monophonic Sound Stereo Sound –more lifelike and realistic –provides data in two different channels - left and right –files require twice as much storage space as mono files Monophonic Sound –tend to sound "flat" and uninteresting –only one channel

8. Humans Nyquist’s Therom: Sample rate should be twice the highest frequency humans: –20 Hz –20,000 Hz

9. According to Nyquist Should sample 40,000 times per second In Reality samples 44,100 Hz

10. Sampling Formulas to determine the size in bits of a digital mono recording: –sampling rate * duration of recording in seconds * (bit resolutions) * 1 to determine the size in bytes of a digital stereo recording: –sampling rate * duration of recording in seconds * (bit resolutions) * 2

11. File size Sample…44,100 :listen to sound determine volume each sample Depth (sample size) is 8 or 16 Channels: 1 or 2 Map each sample to a digit

12. File Size vs. Quality Higher the sound quality, the larger the file Record at highest sampling rate and resolution, i.e., 16-bit stereo, 44.1 kHz

13. File Size =sample Rate*number of channels *bits per sample* 60 seconds =Ask class to figure size for 10 seconds Assume stereo, 8 bit mono

14. Digital Sound File Formats 1.AIF/AIFF (Macintosh) 2.AU (Sun, NeXT) 3.WAV (Windows)