Digital Signal Processing Lecture

The Fundamental is the accumulation of all vibrations that merge together to create what is also known as the Basic tone. Other Vibrations however create a series of harmonic tones. The harmonic is a multiple of the fundamental tone(frequency) i.e. 2 x Fundamental, 3 x Fundamental.

The Amplitude of a sound wave is basically the height of half a wave, i.e. measured from the origin to the peak or trough. The higher/lower(or bigger/smaller) this is determines the level of the sound. For example, a wave with a high amplitude will strike the ear drum harder and therefore the sound is louder.
These measurements are hard to make and therefore sound is actually more often expressed in terms of Sound Level, measured in decibels.

All living creatures have and upper and a lower threshold of hearing which is the quietest or loudest a sound can be but also the frequency a sound can be to hear it. A humans threshold is different from other creature and therefore can hear different things.


Sound intensity = 10log10(Isound/IStandard) DB

The Inverse Square Law implies that the further you are from the source the quiter the sound is. Therefore a sound wave loses intensity over distance.
An echo however is the percieved copying of a sound due to reflection of the sound waves off of objects i.e. a tunnel. Time difference= (d1 + d2)/v
r(t) = s(t-d0/v)+alpha s(t-time dif)

Room reverb is similar to an echo with the exeption that it involves multiple reflections of the sound wave and the can all reflect back to the same point.