How it's tuned
Every outline is a drumhead. Nobody chose a note.
The drum
Each Splash's picture is cut out against nothing. Splashery takes that outline, shrinks it into a grid 96 cells wide, and stretches a drumhead over it: twelve inches across, with waves that cross it at 100 meters per second. Then it solves for the ways that drum can ring. The lowest is the Splash's note. The next fifteen are its overtones, and they are why a fox and a castle on the same tine don't sound alike.
A big, round outline rings low. A small or spindly one rings high. The lowest in the collection is 360° Photo, at 229.6 Hz. The highest is Splat Selector, at 4688.6 Hz. Half of them ring below 434.9 Hz, a few hertz under the A an orchestra tunes to.
The comb
The comb has fifteen tines, three octaves of a five-note scale from G3 to E6. Each Splash plucks the tine nearest its true note. A shelf whose pictures are mostly dark is cut for the minor comb instead, from G3 to F6: AI and Computing, Science, Photoreal, Lab, Arcade, Toys, Earth and Maps, Music, Nature.
A tine's length follows the law for a steel bar, so its pitch goes as one over its length squared. The longest tine is 2.59 times the shortest. Its tone holds the bar's own overtones, at 6.27, 17.55, and 34.39 times the note, and a twin tine tuned a hair sharp, as on a sublime harmonie box.
A shelf plays in the order it stands. A round shape gets one beat; a long, thin one, whose second mode sits close to its first, gets two.
The sand
On a Chladni plate, sand jumps off the parts that move and comes to rest on the lines that don't. Each tine holds one of the Splash's modes, from the second up, and the sand on the stage, made from the picture's own colors, does the same. A tap on the picture strikes all sixteen modes at once, each as strong as its height under your finger, so a blow near the edge sounds and moves differently from one in the middle.
The ripple is slowed down so you can see it. The sound isn't.
Is the solver right?
It was checked against two drums whose answers are known exactly. Each line below is computed when the site is built, and the build fails if one drifts past its limit.
| Drum | Modes checked | Worst error | Limit |
|---|---|---|---|
| A square, 96 cells wide | 8 | 0.072% | 0.3% |
| A disk, 158 cells wide | 7 | 1.08% | 2% |
The square's answers are π² times the sum of two squares. The disk's are the zeros of Bessel functions. The disk is about a percent low because its rim is a staircase of square cells; a Splash's outline is a staircase too, so its note may be off by about that much, a sixth of a semitone.
Needs Ryan's words: Whether to say more about why the site is a music box, in Ryan's own words.