## Fall 2006 Midterm 2 Review: Sound Theory

Sound Theory

1. Frequency is the number of cycles per second and is related to pitch; where amplitude is the maximum height of a wave and is related to volume.
2. Nyquist Theorem says that we need twice as many samples as the maximum frequency in order to represent the original sound; so, if we capture 8000 samples the highest possible frequency we can capture is 4000Hz.
3. 16 bits represents sound and the range of sample values sound can have is 2^16=65,536
4. Clipping is the buzzing noise heard when the sound volume exceeds the maximum that your sound system can handle

Stacy Schwaiger

 For the third question, you need to specify the range of value a sound can have. 65,536 is the total number of values it can have, but what's the range? - Bobby Mathew

If 65,536 is the total number of values, is the range 0-65,355 ?
 No. The values can be negative also, so your range must account for that too. - Bobby Mathew

`-65,537 to 65,536`

that's minus 65,537 to 65,536 it just didn't add the negative sign
 No, that range has REMOVED than 65,536 values which isn't possible. You need to split that number (65,536) into 2, and then do the range. REMOVED the slides for further details. - Bobby Mathew

`-32768 to 32767`

The positive side includes 0, so it only goes up to 32767
 Yes, that's right. - Bobby Mathew

BTW, you don't need to memorize these values. It's handy to know the powers of 2 up to 1,024, but above that everybody uses approximations. So 32k or 64k are quite adequate for 32768 and 65,536, respectively. Colin Potts