Sound Spectrum/Sources (B+45)

  B+45+0 Steel spring pendulum, inverted, vibrates at 10 Hz.
  B+45+5 Giant tuning fork, barely audible, displayed with stroboscope.
  B+45+10 Ultrasound transducers (40 kHz) as both sources and receivers.
  B+45+15 Bell ringing in a jar evacuated with pump.
  B+45+20 Savart's wheel: Toothed wheel and cardboard or air jet.
  B+45+25 Siren: large, electric motor driven.
  B+45+30 Compressed air jet blows through spinning disk with holes.
  B+45+32 Twirling Tube
  B+45+35 Sprockets on shaft rotate against a card to make sound.
  B+45+40 Caruga horn: Varigated tube to blow through
  B+45+41 Feedback from microphone/speaker system.
  B+45+42 Hoot Tube
  B+45+45 Galton's whistle: Compressed air whistle.
  B+45+50 Helmholtz resonators drive radiometer vanes, using tuning forks.
  B+45+51 Helmholtz Resonators with tuning forks and a candle
  B+45+55 Casio electronic synthesizer with amp and speaker.