1. Terms cont’d.
Dynamics

2. Dynamics 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 dB

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

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

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

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

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

26. Musical Dynamics 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
Before After
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”.

33. Loudness Wars
A recent (within the past 20 years or so) production technique to obtain more density from recorded audio.
The selected audio is compressed and normalized several times to even out the dynamic range, but enable the entire sample to be louder.
It is not only louder, but saturated with signal.
Each track is processed this way, and the resulting mix is very dense, and loud.