We don’t really get out much, but we have noticed that there are brightly painted upright pianos in public places these days. Research indicates that these pianos are being placed by small, independent local organizations, most of which aim to spread the joy of music and encourage a sense of community.
[Sean and Mike] took this idea a couple of steps further with Quaver, their analog looping piano. Both of them are maker/musicians based in Lancaster, Pennsylvania, which happens to be a hot spot for public pianos. [Sean and Mike] often stop to play them and wanted a good way to capture their impromptu masterpieces. Quaver is an antique upright that has been modified to record, save, loop, and upload music to the internet. It does all of this through a simple and intuitive user interface and a Raspi 2. Quaver works a lot like a 4-track recorder, so up to four people can potentially contribute to a song.
The player sits down, cracks their knuckles, and presses our personal favorite part of the interface: the giant, irresistible record button. A friendly scrolling LED matrix display tells them to start playing. Once they are satisfied, they press the button again to stop the recording, and the notes they played immediately play back in a loop through a pair of salvaged Bose speakers from the 1980s. This is just the beginning of the fun as you play along with your looping recording, building up several voices worth of song!
The development of Quaver was not without its problems. Pianos are difficult to mic in any environment, especially the echo-prone food court of your average shopping mall. Because a piano’s soundboard is so large, the sound is never focused in any one place. An electronic engineer named [Ezra Charles Helpinstill] created electromagnetic bar pickups in the early 1970s, and named them after himself. They quickly became the amplifying device of choice for piano stars like [Elton John]. Helpinstill pickups attach to the piano soundboard with magnets and clamps. They only sense vibration, so there is no need to worry about feedback.
Amplification wasn’t the only issue they encountered. When a user resets the piano, the Pi reboots. This can take up to 30 seconds in standard Raspbian, which wouldn’t work well in a public setting. People would quickly lose interest and walk away. [Mike] ended up compiling his own Linux kernel using Buildroot and was able to get the boot time down to an admirable 2.9 seconds.
Check out the Quaver video demo and then go listen to the loops that people have uploaded.