1. Terms cont’d. Dynamics

2. Relative loudness or softness of a sound. A trumpet soft is still louder than an acoustic guitar played loud!

3. Decibel A measurement of volume. Not relative like musical dynamics, but objective.

4. SPL - Sound Pressure Level Auditory threshold at 1 kHz 0 dB

5. SPL - Sound Pressure Level Light leaf rustling, calm breathing 10 dB

6. SPL - Sound Pressure Level Very calm room 20 - 30 dB

7. SPL - Sound Pressure Level Normal conversation at 1 m 40 - 60 dB

8. SPL - Sound Pressure Level Washing machine, dish washer 50-53 dB

9. SPL - Sound Pressure Level TV (set at home level) at 1 m approx. 60 dB

10. SPL - Sound Pressure Level Handheld electric mixer 65 dB

11. SPL - Sound Pressure Level Passenger car at 10 m 60 - 80 dB

12. SPL - Sound Pressure Level Hearing damage (over long-term exposure, need not be continuous) 85 dB

13. SPL - Sound Pressure Level Traffic on a busy roadway at 10 m 80 - 90 dB

14. SPL - Sound Pressure Level Jack hammer at 1 m approx. 100 dB

15. SPL - Sound Pressure Level Jet engine at 100 m 110 - 140 dB

16. SPL - Sound Pressure Level Hearing damage (possible) approx. 120 dB

17. SPL - Sound Pressure Level Vuvuzela horn at 1 m 120 dB

18. SPL - Sound Pressure Level Threshold of pain 130 dB

19. SPL - Sound Pressure Level Jet engine at 30 m 150 dB

20. SPL - Sound Pressure Level M1 Garand rifle being fired at 1 m 168 dB

21. SPL - Sound Pressure Level.30-06 rifle being fired 1 m to shooter's side 171 dB (peak)

22. SPL - Sound Pressure Level Rocket launch equipment acoustic tests ~165 dB

23. SPL - Sound Pressure Level Stun grenades 170 - 180 dB

24. SPL - Sound Pressure Level Theoretical limit for undistorted sound at 1 atmosphere environmental pressure ~194.094 dB

25. SPL - Sound Pressure Level Shockwave (distorted sound waves > 1 atm; waveform valleys are clipped at zero pressure) >194 dB

26. Musical Dynamics A piece of music may change in dynamic level throughout. Live music is especially good for hearing dynamics. Subtle variations in a performance by musicians, being sensitive to the sounds around them.

27. Musical Dynamics A recording on CD is also excellent for capturing dynamics, as the available dynamic range is far better than on other recording media (tapes, records, and other analog formats).

28. Compression Radio and mp3 formats are not ideal for hearing dynamics. The recording is modified with Compression. Compression “squeezes” the dynamic levels, making loud sounds softer, and soft sounds louder.

29. Compression

30. Normalize A way of modifying sound to “ peak ” at the maximum volume. Analysis of a computer sound byte will display the current volume level, as well as show the maximum potential volume before distortion / clipping / overload.

31. Normalize BeforeAfter Add compression

32. The Loudness Wars The movement in audio recording and production that strives to get the most audio density into each recording. Record a sound, compress it, normalize it, compress it, normalize it, compress it, etc. Eliminates the distinction between loud and soft - everything is loud or “ hot ”.