- Jan. 25, 2021.
- Jan. 27, 2021.
- Feb. 3, 2021.
- Feb. 8, 2021.
- Feb. 10, 2021.
- Feb. 13, 2021.
- Earl's Breakdown by Earl Scruggs and the Foggy Mountain Boys. Notice that to make high notes, banjo player
Early Scruggs moves his left hand down the neck of the banjo closer to the body. This makes the length of the string shorter, so
that it has a higher-frequency fundamental (n=1) standing wave. Also notice the unusual technique around 0:15 --
Scruggs uses the knobs usually used to tune the banjo and adjusts them while playing to produce a ``glissando'' effect.
The tuning knobs change the tension in the string, which changes the wave speed and therefore the standing-wave frequency.
- Feb. 17, 2021.
- Foggy Mountain Breakdown written by Earl Scruggs, performed
by Earl Scruggs and Men With Banjos Who Know How to Use Them. On the far right is the legendary Earl Scruggs, the famous bluegrass
banjo artist who is also seen in the previous video, decades earlier. On the far left is Steve Martin, famous comedian and also an accomplished banjo artist. All this music is due entirely
to standing waves on strings. The performers pluck the strings to excite standing waves, and the frequency of the standing
wave is given by the "fixed-fixed" formula we covered in class. Notice how each performer places his fingers on the neck of the banjo
to play different notes. This changes the length of the string, and therefore the standing wave frequencies (and thus the notes).
(Video is from The David Letterman Show.)
- Feb. 22, 2021.
- First recordings of the human voice. The first known recording of the
human voice is shown on this Web site, and is from April 9, 1860 -- before the US Civil War, and 17 years before Edison
invented the phonograph. The recording was made using an phonautograph technique, but there was no way to play the recording
back at the time. We have since developed technology that allows us to play back these early recordings.
Dr. David G. Simpson: