TutorDave Hickman Room NoC155 Emaild.hickmanstaffs.ac.uk

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Tutor Dave Hickman Room No C155
Email d.hickman_at_staffs.ac.uk
Music Instrument Technology 1 CE00138-1 Performa
nce Instrument Technology 1 CE00142-1
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Indicative Content

• Introduce the design, construction and
  application of various mechanical and
  electromechanical musical instruments.
• Explore the physical properties of these
  instruments
• Analyse acoustic vibrational systems inherent
  in their construction and usage.
• The module will analyse various instrument
  technologies with examples from string, wind
  percussion families.

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Learning Outcomes

• Analyse the properties of acoustic instruments.
• Demonstrate the fundamentals of sound propagation
  by acoustic instruments.

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Indicative Reading Sound and Recording, An
Introduction. F. Ramsey and T McCormick.Focal
Press, 1996. ISBN 0-240-51487-4 The Science of
Sound. 3rd Ed Rossing, Moore Wheeler.Addison
Wesley,2002. ISBN 0-8053-8565-7. Musical
 Acoustics  3rd  Ed.   Donald  Hall.Brooks  
 Cole.  2002. ISBN  0-534-37728-9
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Week Topics Covered 1 Introduction,
Physics of sound (F14) 2 Instrument
classifications (F14) 3,4,5 Practical
work (E8) 6 String brass instruments
(F14)7 Practical work (E8)8 Woodwind
instruments (F14) 9 Practical work
(E8)10 Percussion and ensemble (F14)
11,12 Practical work (E8)
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Assessment for Instrument Technology One written
assignment 40 of module (music AND performance
students)
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Notes and additional information, module handbook
etc on my web page URL is www.staffs.ac.uk/dh5
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Week one

• simple definition of sound
• Sound propagation
• speed of sound/wavelength/frequency
• Pitch
• Timbre
• Harmonics and frequency
• The Decibel/ sound pressure level
• weighting filters

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Vibrating sound source example
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Sine wave
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• Where V is the speed of sound, which in air at 20
  degrees Celsius is 340ms-1
• And f is the frequency in Hertz (which is cycles
  per second)
• And ? is the wavelength. (in metres)

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where tempinKelvins is 273tempinCelsius
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• If a violin is recorded and the frequency
  measured at 220Hz,
• calculate its wavelength (assume room
  temperature to be 22 degrees Celsius).

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solution
metres
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Human hearing

• Generally regarded as the lowest frequency of
  human hearing is at around 20 Hz taking the speed
  of sound at 340 metres per second this gives a
  wavelength of 340/20 17 metres, a very long
  wavelength.
• the generally regarded upper limit of the human
  ear frequency response of 20kHz this gives
  340/20000 1.7 centimetres very short wavelength.

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• Pitch
• The frequency of a sound is perceived as the
  pitch and is defined as the number of these
  compressions and rarefactions which occur per
  second, that is the rate at which the air
  pressure changes
• sound waves that repeat with regularity over
  time. Such sounds are characterised by a dominant
  frequency or pitch.
• in fact that it is really only repetitive sounds
  that have determinate pitch i.e. sounds that
  regularly repeat. Sounds may be continuous or
  transient
• perceived pitch does depend on sound level,
  duration of note and envelope of note

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• Timbre
• The characteristic sound of a waveform (a musical
  repetitive waveform whether it is produced by a
  violin or a trumpet or anything!) is called its
  timbre. Timbre can also be referred to as tone
  colour
• timbre also depends on sound level and frequency

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• Violin waveform

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Trumpet waveform
Amplitude
Time
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Harmonics and Frequency

• regardless of complexity waves can be represented
  as a line spectrum.
• Waveforms can be broken down into a series of
  harmonics
• known as Fourier analysis

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The Decibel

• the concept of sound pressure levels (SPL). with
  relation to the normally accepted threshold of
  human hearing.
• The decibel is based on the logarithm of the
  ratio between two numbers

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• P1 is the pressure being measured
• P2 is the threshold of Human hearing.
• 2 x 10-5 Nm-2 or 20 ?Pa (0.00002 Nm-2)

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• Hence if a sound were measured at 0.12 Pa then
  this would be equivalent to
• 75.56 dB SPL
• This means that the measured sound is 75.56 dB
  greater than the established reference threshold
  of hearing.

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• Decibels type of sound
• 130 Artillery fire at close proximity (threshold
  of pain)
• 120 amplified rock music near jet engine
• 110 Loud orchestral music, in audience
• 100 electric power tools
• 90 Bus or lorry interiors
• 80 Car interior
• 70 Average street noise loud telephone bell
• 60 Normal conversation business office
• 50 Restaurant private office
• 40 Quiet room in home
• 30 Quiet lecture hall bedroom
• 20 Radio, television, or recording studio
• 10 Soundproof room
• 0 Absolute silence (threshold of hearing)

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• If a trumpet is measured at 1.5Pa at the bell of
  the horn, give the level of the sound in dB SPL
• If the trumpet sound in 1) above is measured at
  300Hz, calculate its wavelength (assume room
  temperature to be 22 degrees Celsius).
• If a sound doubles in frequency i.e. from 240Hz
  to 480Hz what musical term describes this
  doubling in frequency.
• Briefly describe what is meant by spectral
  content of a complex waveform.
• Look at the longitudinal waveform animation on
  the website http//www.kettering.edu/drussell/Dem
  os.html
• Using Cooledit or Soundforge construct a square
  wave and analyse it using Fourier analysis, do
  the same thing with a sine wave, a triangular
  wave and random noise. Try to identify the
  fundamental and all harmonics.
• Read all the notes from this week and make sure
  you understand them.