View Full Document

Introduction to Processing Digital Sounds



View the full content.
View Full Document
View Full Document

16 views

Unformatted text preview:

Introduction to Processing Digital Sounds part 1 Barb Ericson Georgia Institute of Technology Oct 2009 Intro Sound part1 Learning Goals Learn about sounds How do we hear How do we digitize sound Why do we digitize sound How is digitized sound represented How to play a sound in Java How to create Sound objects How to play them How to explore them Intro Sound part1 How does Hearing Work The outer ear catches sounds The eardrum vibrates The inner ear translates the vibrations to nerve impulses for the brain to interpret Intro Sound part1 Acoustics the physics of sound Sounds are waves of air pressure Sound comes in cycles The frequency of a wave is the number of cycles per second cps or Hertz Complex sounds have more than one frequency in them The amplitude is the maximum height of the wave Intro Sound part1 Volume and Pitch Our perception of volume is related logarithmically to changes in amplitude If the amplitude doubles it s about a 3 decibel dB change A decibel is a ratio between two intensities 10 log10 I1 I2 As an absolute measure it s in comparison to threshold of audibility 0 dB can t be heard Normal speech is 60 dB A shout is about 80 dB Our perception of pitch is related logarithmically to changes in frequency Higher frequencies are perceived as higher pitches We can hear between 5 Hz and 20 000 Hz 20 kHz A above middle C is 440 Hz Intro Sound part1 Try It Attach a microphone to your computer Open the Windows MediaTools folder Drag the mediatools v5 sa image file and drop it on SqueakVM exe This will start Squeak with the media tools loaded Click on the Sound Tools window It will expand Click on Record Viewer and Record And do high and low sounds in the microphone Notice that high sounds have more cycles per second Click on Quit to exit Squeak Intro Sound part1 Sound Tools in Squeak Intro Sound part1 Digitizing Sound In calculus you learn to estimate a curve by creating rectangles We can do the same to estimate the sound curve Analog to digital conversion



Access the best Study Guides, Lecture Notes and Practice Exams

Loading Unlocking...
Login

Join to view Introduction to Processing Digital Sounds and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Introduction to Processing Digital Sounds and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?