Harmonica
Michael K. McBeath
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Harmonica Licks
 
FilthyRich - Ball&Sultan TooMuchFun - Ball&Sultan Ball&Sultan
Harpburn - RodPiazza BluesInTheDark - RodPiazza AlphabetBlues - RodPiazza
AmazingGrace - TerryMcMillan BluesRiff - Portnoy OldHardRain - AnnieRaines
WorkSong - PaulButterfield Juke - LittleWalter BringItOnHome - SonnyBoy

Rounders Blues Samples

Hohner's Featured Artists

The Blues Web

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Harmonica References

 

 
 
 

Hohn er USA Home Page

Harp-L - Bulletin Board and Archives

Society for Preservation and Advancement of the Harmonica

The Blues Harp Home Page

Harmonica Publications

Harmonica Artist's Home Pages

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The Doppler Shift and the Doppler Illusion
The Doppler shift is the drop in frequency that occurs as a moving auditory source approaches and passes by an observer (i.e. as the observed wavefront changes from its initial compressed state to its a final expanded state). The Doppler illusion is the dramatic rise and fall in pitch that human observers typically experience with Doppler-shifted stimuli. The illusion is caused by the dynamic change in intensity and is relatively independent of the change in frequency. (The rise and fall of pitch with dynamic intensity also opposes the previously well known effect of discrete intensity change. There, low to midrange frequencies (below about 3KHz) typically change in pitch inversely with discrete intensity change.)

 

 
 
 

Hear a Doppler Shifted Tone (Listen as the pitch rises and falls with intensity.)

Shifts in pitch can be heard when listening to natural sources that result in a relatively constant observed frequency, but that sweep up and down in intensity. One example is the pitch change that occurs with the movement of passing insects like mosquitos. The motion is slow enough so that virtually no Doppler shift in frequency occurs, yet the change in intensity can produce a pitch change.

Hear a Swarm of Mosquitos (Notice the pitch modulations.)

In general, when ever a mosquito or other insect flies by your ear, any change in pitch that you experience is due to the dynamic intensity change, and is an example of the Doppler illusion.

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Catching an Approaching Ball

Two Major cues used to judge approach of a ball:

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[Last updated September 9, 1997: by M. K. McBeath]