Harp game: play a harp online, then echo the tune

Echo Harp is a harp you can play right in your browser. Click or tap once to start the sound, then sweep a finger or your mouse across the eleven glowing strings and they bend, spark and ring. Every string is tuned to the same five-note scale, so there are no wrong notes when you play freely.

How to play

1. Tap or sweep the strings. Long strings on the left are low, short strings on the right are high. Click or tap the harp once first so your browser lets it make sound. Before that, on a computer, the strings move under your mouse but stay silent.
2. Pick a mode from the top-right corner: Play, Echo or Daily.
3. Listen, then echo. In Echo and Daily, the harp lights up and plays a short tune. Play the same strings in the same order. Each round adds one note.

Send a friend a tune

In Play mode, pluck four to sixteen notes in a row. A button appears that turns those notes into a link. Whoever opens it hears your tune, then has to echo it back one round at a time. When they finish, they can play a tune of their own and send it back.

Why it always sounds good

The eleven strings cover two octaves of the D major pentatonic scale: D, E, F♯, A and B. A pentatonic scale has no notes a half step apart, so any two strings sound fine together. Many wind chimes and folk tunes use pentatonic scales too.

The sound isn't a recording. Each string's tone is generated in your browser with the Karplus-Strong plucked-string model: a short burst of noise circulates through a delay the length of one vibration and loses a little brightness each pass, which is roughly what a real string does. Sweep faster and the note gets brighter and louder.

Playing on a keyboard

On a computer, the home row plays the strings from low to high: A S D F G H J K L ; '. These keys work once you have clicked the harp (the page does not see key presses before that). In Play mode, after your first click, you can also just move the mouse across the strings.

Questions