Sound Training 2B

1. Sound Training 2B 23/30th November 2011 JP & JC

2. Objectives • Understand some theory about sound and the equipment used • Learn how to fully build and plug in a sound rig for a typical band night in Rubix • Learn how to soundcheck and mix a drum kit (and maybe other instruments)

3. Sound Theory

4. Sound in Air & the Ear Sound is a type of wave, which our ears detect and convert into electrical signals

5. Wave/Sound Properties • Amplitude • Frequency (1/Time Period) • Wavelength

6. The dB (decibel) • “The decibel (dB) is a logarithmic unit that indicates the ratio of a physical quantity (usually power or intensity) relative to a specified or implied reference level.” • dBu • dBF • dB(SPL)

7. Loudness (According to the Ear) dBA “weighting” SPL follows the 40 phon curve dBB “weighting” SPL follows the 70 phon curve dBC “weighting” SPL follows the 100 phon curve

8. Common dB(A) levels • 20 – rustling leaves • 40 – bird singing / quiet talking • 70 – toilet flushing • 90 – heavy city traffic • 110 – rock band • 130 – pneumatic drill • 150 – jet plane close by

9. The Law (at work) • 80 dBA Leq over 8h (or 135dBC instantaneous) - ear protection available on request • 85 dBA Leq over 8h (or 137dBC instantaneous) - ear protection issued • 87 dBA Leq over 8h (or 140dBC instantaneous) - max legal level (after reduction by protectors)

10. Exposure & Recovery

11. Signal Sources, Speakers& the bits in between

12. Microphone Types • Dynamic (we use live) • Condenser (we use live) • Ribbon • Piezoelectric

13. Dynamic Mics • High SPL sources (e.g. vocals, drums, guitar) • No power required • Rugged design

14. Condenser Mics • Low SPL sources • Can be good for HF sounds e.g. cymbals, flute • Require power (phantom power)

15. Mic Pickup Patterns Typically used on stage

16. Other Sources • Some instruments already output an electrical signal (e.g. keyboard, bass guitar, laptop) • If unbalanced source (to be explained later) then usually plugged in via a DI (direct injection) box

17. Speakers • Many sizes • Certain sizes reproduce sound more efficiently than others • Therefore, often many speaker sizes in one box

18. Active / Passive In active systems, a crossover is used to split up the sound into frequency ranges to send to different amplifiers and speakers

19. Active / Passive Passive systems amplify the sound before splitting the signal to go to different speakers – only one amp required You may notice the wedges (aka monitors) have an active/passive switch – we usually use them in active mode

20. Active / Passive WARNING!!! Double definition! Active/Passive can also refer to whether a piece of equipment has amplifiers built in. E.g. RCF drum fills are a type of ‘active’ system

21. FOH & Monitor Speakers • FOH speakers are used so audience can hear the act (usually just left and right speakers) • Monitors are so the act can hear themselves play clearly (many sets of speakers – maybe 1 per band member)

22. Point Source Speakers • Many speakers are pointed as to cover the listening area • E.g. our Turbosound rig

23. Line Array Speakers • Lots of small speakers joined together to work as one big speaker • E.g. our d&b rig

24. Feedback • Certain frequencies of sound get stuck in a loop between the microphone and the speaker • The level of that frequency increases and causes the often painful ‘squeeling’ noises

25. Signal Path

26. Sound Cabling • Balanced / Unbalanced • Connector types

27. Signal Processing

28. Frequency Control • “Equalisation” or “EQ” • 2 main types • Parametric • Graphic

29. Filters • Low Pass (LPF) • Band • High Pass (HPF)

30. Amplitude Control – Compressors / Limiters “Reduce dynamic range” “Gets rid of peaks in volume”

31. Amplitude Control - Gates Let sound ‘through’ when above a set level

32. Effects – Delay

33. Effects – Reverb

34. Phase

35. Now the fun bit…