-- by David Swink, February 2017
Sound waves can be generated on a computer using math equations. The tone and chord examples shown below are based on Javascript algorithms developed by Rodrigo Siqueira and found at this site. And while tones can only be created singly, pseudo-chords can be created by "rippling" through a series of short tones, as has been done here.
Note that, while I am a musician, I am not a music theorist, so I don't know which chord types (beyond major and minor keys) are truly useful. And while my chords are merely 3-tone, perhaps 4-tone would be nicer. How many octaves should represented for practical purposes? Are the "black key" chords all that useful? Anyone wishing to enlighten me and add value to the presentation may contact me at swinkdb@gmail.com.
| Octave4 | Octave5 | Major chord | Minor chord | Aug 5th | Dim 5th |
|---|---|---|---|---|---|
| C4 | C5 | C,E,G | C,Eb,G | C,E,G# | C,Eb,Gb |
| Db/C# | Db/C# | Db,F,Ab | Db,E,Ab | Db,F,A | Db,E,G |
| D4 | D5 | D,F#,A | D,F,A | D,F#,Bb | D,F,Ab |
| Eb/D# | Eb/D# | Eb,G,Bb | Eb,Gb,Bb | Eb,G,B | Eb,Gb,A |
| E4 | E5 | E,G#,B | E,G,B | E,G#,C | E,G,Bb |
| F4 | F5 | F,A,C | F,Ab,C | F,A,C# | F,Ab,B |
| Gb/F# | Gb/F# | Gb,Bb,Db | Gb,A,Db | Gb,Bb,D | Gb,A,C |
| G4 | G5 | G,B,D | G,Bb,D | G,B,D# | G,Bb,Db |
| Ab/G# | Ab/G# | Ab,C,Eb | Ab,B,Eb | Ab,C,E | Ab,B,D |
| A4 | A5 | A,C#,E | A,C,E | A,C#,F | A,C,Eb |
| Bb/A# | Bb/A# | Bb,D,F | Bb,Db,F | Bb,D,Gb | Bb,Db,E |
| B4 | B5 | B,D#,F# | B,D,F# | B,D#,G | B,D,F |
"Carry Me Back To 'Ol Virginny"
Caveat 1: Since repeated clicking of chords creates a lot of complex sine wave computations in Javascript, your browser may create those chords ever slower over time. Solution now: Refresh the page and continue. Solution in future: Move the algorithms outside of Javascript, probably into Perl.
Caveat 2: I have not been able to find a list of tonal frequencies for use in the above table. Instead, I've created my own list empirically "by ear", which works for me on my browser and computer. Hopefully it will work for you as well.