2. Sound Processing

3. Arithmetic on Sound Sound is an array of amplitudes (numbers) –Adding two sounds together –Make a sound louder or softer –Blends of two sounds –Echos

4. Adding two sounds Laser Guns Distress + = New Sound

5. Adding Sounds Demo Cool Edit –Edit -> Mix Paste

6. Adding two sounds Laser = laser gun sound; Warn = warning message; NewSnd = new array(Laser.length); for (each index i in NewSnd) {NewSnd[i]=Laser[i]+Warn[i]; }

7. Making a sound louder

8. Amplify Sound Demo Cool Edit –Transform -> Amplitude -> Amplify

9. Making a sound louder for (each index i in oldSound) {newSound[i]=oldSound[i]* 3 ; }

10. General Amplify algorithm amp = 3.0; three times as loud for (each index i in oldSound) {newSound[i]=oldSound[i]* amp ; }

11. General Amplify algorithm amp = 0.5; half as loud for (each index i in oldSound) {newSound[i]=oldSound[i]* amp ; }

12. Blending two sounds Whistle Words 90% whistle 10% words 50% whistle 50% words 10% whistle 90% words

13. Blending Sounds Demo Cool Edit –Transform -> Amplitude -> Amplify –Edit -> Mix Paste

14. Blending two sounds B = blend value between 0.0 and 1.0 for (each index i in Snd1) {newSnd[i]=(1.0-B)*Snd1[i]+ B*Snd2[i]; }

15. Singing a Round by yourself Row Row Row your boat

16. Singing a Round by yourself Row Row Row your boat Sing in a round

17. Singing a round by yourself Time delay + =

18. Singing a round by yourself Demo Cool Edit –Edit -> Mix Paste

19. Singing a round by yourself song = the original song; delay = how many samples to delay; newSng = new array(song.length+delay); for (each index i in song) {newSng[i] = song[i]; } for (each index i in song) {newSng[i+delay] = newSng[i+delay]+song[i]; }

20. Echoes An echo occurs because sound returns delayed and softer after bouncing off of something Original Canyon Echo (large delay) Room Reverb (small delay)

21. Echoes Demo Cool Edit –Transform -> Delay Effects -> Echo

22. Echoes sound = the original sound; delay = how many samples to delay; softness = 0.1; newSound = new array(sound.length+delay); for (each index i in sound) {newSound[i] = sound[i]; } for (each index i in sound) {newSound[i+delay] = newSound[i+delay] + sound[i]*softness; }

23. Speech Recognition Converting an audio signal into text Problems –There is no way to write this sentence in english to two too

24. Speech Recognition - problems Diversity of speech –I want a cookie Confused recognition –I want to fly –Eye want to cry

25. Speech Recognition - success Small number of words –about 1000 Clear differences among words Train recognizer to person’s voice

26. Speech synthesis Converting text into sound Concatenation of sound –Words go together funny Prosody, the inflection that you speak with –Variation changes meaning That is yours