1. WOODWIND INSTRUMENTS MUSICAL ACOUSTICS
The Science of Sound, Chapter 12
The Physics of Musical Instruments, Chapters 15 and 16

2. WOODWIND INSTRUMENTS

3. OSCILLATIONS IN A PIPE
ONE WAY TO STUDY THE RESONANCES OF A PIPE (OR A WIND INSTRUMENT) IS TO MAKE A GRAPH OF ITS ACOUSTIC IMPEDANCE AS A FUNCTION OF FREQUENCY
ACOUSTIC IMPEDANCE IS SOUND PRESSURE DIVIDED BY VOLUME VELOCITY Z = p/U

4. APPARATUS FOR GRAPHING THE ACOUSTIC IMPEDANCE OF WIND INSTRUMENTS
(from Chap. 11)
(The tube filled with fiber-glass provides a constant volume flow from the driver, so that the pressure recorded by the microphone is proportional to acoustic impedance)

5. HOW A CLARINET WORKS
A pulse of excess pressure propagates down the pipe (a,b) and is reflected as a pulse of underpressure (c,d), which returns to help draw the reed valve shut.
In (e)-(h) the process repeats with this negative pulse, which reflects as a positive pressure pulse.

6. FEEDBACK FEEDBACK—USE OF THE OUTPUT TO CONTROL OR INFLUENCE THE INPUT
NEGATIVE FEEDBACK (IN HI-FIDELITY AMPLIFIERS) STABLIZES A SYSTEM, REDUCES DISTORTION
POSITIVE FEEDBACK (IN OSCILLATORS OR MUSICAL INSTRUMENTS) CAUSES INSTABILITY OR OSCILLATION

7. INPUT VALVES

8. REED-GENERATOR CONFIGURATIONS
INWARD STRIKING Corresponds to a woodwind reed
(b) OUTWARD STRIKING Corresponds to brass player’s lips
(c) SIDEWISE STRIKING Alternative model of brass player’s lips

9. TWO TYPES OF PRESSURE CONTROLLED VALVES
FLOW VELOCITY vs AIR PRESSURE IN A CLARINET

10. HOW A CLARINET WORKS
A pulse of excess pressure propagates down the pipe (a,b) and is reflected as a pulse of underpressure (c,d), which returns to help draw the reed valve shut.
In (e)-(h) the process repeats with this negative pulse, which reflects as a positive pressure pulse.

11. CLARINET - RANGE OF PRESSURE

12. CYLINDRICALPIPE RESONANCES (from Chap. 4)
CONICAL PIPE RESONANCES
(see Fig. 12.7)

13. WHAT ABOUT TRUNCATED CONES?
ARE THE RESONANCES HARMONIC?

14. RESONANCE FREQUENCIES OF OPEN AND CLOSED PIPES, CYLINDRICAL AND CONICAL

15. INPUT IMPEDANCE OF THE CLARINET
EFFECT OF REGISTER HOLES
3 REGISTERS OF A CLARINET

16. EFFECTS OF REGISTER HOLESp p p

17. THREE NOTES ON A CLARINET
WAVEFORM
SPECTRUM

18. LATTICE OF OPEN TONE HOLES
CUTOFF FREQUENCY

19. EFFECT OF REED STIFFNESS

20. A CONICAL BORE ACTS LIKE A “CLOSED PIPE”

21. CONTRABASS SAXOPHONE
LARGEST WOODWIND INSTRUMENT

22. OBOE
WAVEFORM
SPECTRUM

23. BASSOON

24. BASSOON

25. EARLY WOODWIND INSTRUMENTS

26. BAGPIPES
HIGHLAND
BAGPIPES

27. NORTHUMBRIAN BAGPIPE

28. DIRECTIONAL RADIATION

29. TYPICAL BLOWING PRESSURES IN WOODWINDS
TYPICAL BLOWING PRESSURES ACROSS THE MAIN COMPASS OF CLARINET
ALTO SAXOPHONE, OBOE, AND BASSOON, FOR PIANO AND FORTE PLAYING
Fuks and Sundberg, 1996

30. SPECTRAL ENVELOPE OF (IDEALIZED) WOODWIND

31. FLOW CONTROL OF AIR BLOWN ACROSS A BOTTLE AND A FLUTE
CONSTRUCTION OF A FLUTE

32. PRESSURE STANDING WAVES IN A FLUTE
IF THE CORK IS PULLED OUT, ALL NOTES ARE FLATTENED BUT UPPER MODES ARE AFFECTED MORE (BECAUSE THE EFFECTIVE POSITION OF THE PRESSURE MODE AT THE BLOWING END IS BEYOND THE CORK)

33. BLOWING PRESSURE USED
BY EXPERIENCED FLUTE
PLAYER FOR NOTES OF
DIFFERENT PITCHES
LIP OPENING WIDTH AND HEIGHT
USED BY EXPERIENCED FLUTE
PLAYERS TO PRODUCE NOTES
AT DIFFERENT PITCHES AND
VOLUME LEVELS

34. FLUTE p
OPENING TONE
HOLES p
REGISTER
HOLES

35. TYPICAL SPECTRA FOR LOUD AND SOFT NOTES OF VARIOUS PITCHES PLAYED BY 4 DIFFERENT FLUTISTS. THE SAME REFERENCE LEVEL IS USED IN EACH CASE Fletcher, 1975

37. BAROQUE RECORDER
TYPICAL
FINGERING
CHART FOR A
BAROQUE
RECORDER

38. BLOWING PRESSURE FLUTE, RECORDER

39. Assignment for Wednesday:
Read Chapter 13
Exercises 1-6 p. 270