Download Sine wave - Truth Recordings

WEEK 12
Revision class 2
Threshold of pain 140dB
Threshold of hearing is 0dB
Ranges of Hearing
The accepted range of hearing is 20Hz20kHz
The accepted dynamic range of
hearing is 120dB
Stringed Instruments
The standing wave constraint of
stringed instruments is at each
end of the medium there must
be a node
Open Pipe Instruments
Include: Flute, recorder
The standing wave constraint of
open pipe instruments is at
each end of the medium there
must be an anti-node
Closed Pipe Instruments
Trumpet, Sax, Trombone
The standing wave constraint of
closed pipe instruments is an
anti-node at one end and a
node at the other
Reed Instruments
Mechanical reed – sax, clarinet, bassoon
Lip reed – trumpet, trombone, tuba
Air reed – flute, recorder, organ pipe
Simple Waveforms
Sine
Square
Triangle
Sawtooth
Harmonic Content
Sine wave: no harmonics
Square wave: All odd harmonics at inverse
amplitudes
Triangle wave: All odd harmonics at inverse
squared amplitudes
Sawtooth wave: All harmonics (odd and
even) at inverse amplitudes
Decibel Revision
• Reference values for Power, Voltage
and SPL are:
1. dBSPL for Sound Pressure Level - 20µPa
2. dBV for Voltage - 1 volt
3. dBU for Voltage - 0.775 volts
4. dBP for Power (Watts) - 0.001 watt