Instruments and acoustics

Guitar chord boxes and TAB (one fingering, two notations that face opposite ways)

Five basic guitar chords (C, G, Am, F, Bm) written twice and lined up: chord boxes on top, TAB below. In the box the low E string is on the left, the thick top line is the nut, x and o sit above and the numbers below name the fingers; F and Bm show the barre as a long oval. In the TAB the top line is the high e. The two face opposite ways, so each labels its strings.

This drawing comes from one YAML file. No shape was moved by hand.

Notes in the source (in Japanese)

Source (YAML)

examples/gallery/404-ギターのコード表とTAB譜.zumen.yaml

More in this field

• Guitar frets are a geometric series, and the saddle must still be moved back to play in tune
• Hall acoustics: delay is nothing but a difference in path length — one millisecond is 0.34 m
• A piano action: the jack lets go just before the string, so nothing is pushing the hammer at impact
• Music engraving: the staff space is the unit for every measurement, and the stem is 3.5 of them
• Frets crowd together as you climb because what is divided into twelve is not a distance but a ratio: each semitone multiplies by 2^(1/12), so the twelfth fret lands at exactly half the string and everything beyond it repeats at half size
• The black keys are grouped in twos and threes so that a hand can find its place without looking — twelve evenly spaced keys would give no landmark at all — and 88 turns out to be seven octaves plus four: three keys added below and one above
• The strings run left to right from high to low and the louder the instrument the further back it sits, so the seating plan is itself a balance control — and "double wind" or "triple wind" names the size of the orchestra by counting only the woodwind
• A polar plot of how much a microphone picks up from each direction. The three familiar shapes are not separate inventions but one formula at its ends and middle — omnidirectional, cardioid and figure-of-eight are A = 1, 0.5 and 0 in r = A + (1 - A)cos θ. Solving the same formula gives the dead angles: 180 degrees for a cardioid, 90 and 270 for a figure-of-eight.