Saturday, February 6, 2021

A Stylus-operated Musical Instrument that Sings!

The Stylophone Museum's newest exhibit isn't an official Dubreq brand Stylophone, but it has some similarities that make it welcome here. The Gakken NSX-39 "Pocket Miku" is an intriguing little instrument that was released in 2014, but I became familiar with it only this week, thanks to a trip down a rabbit hole while searching for something else on the web. 

The instrument is just one iteration of a cartoon/computer hybrid known as Hatsune Miku that blends the persona of a 16-year-old, turquoise-tressed female anime character with the Yamaha  NSX-1 sound chip and Vocaloid singing voice synthesis technology. The chip's digital voice is modeled on the real voice of anime voice actress Saki Fujita. There are lots of demos of the instrument to listen to on YouTube.

Like an official Stylophone, the NSX-39 is played with a stylus on a metal keyboard. There is also a ribbon controller along the top edge of the keyboard. There's no physical barrier between the keys and the ribbon, so you can move the stylus from one to the other seamlessly. The stylus snaps into the base of the instrument for storage. Three AAA batteries power the NSX-39, or it will run on USB power. (More on that later.) On power-up, the instrument plays voice-synthesizer sounds that approximate solfege ("do-re-mi") vocalizations for the eight notes of the major scale. You can play a vowel sound across the keyboard instead, with the push of one of five buttons labeled A, I, U, E, and O. Another button adds vibrato to the voice.

A shift button can be used to access additional functions, such as playing preset lyrics to what I would assume are Japanese folksongs. (Unfortunately, I don't read Japanese beyond a few simple words, so I can't sing along.) Pressing shift and an arrow button will raise or lower the singing pitch by one octave. Another button adds vibrato to the voice. A combination of the vibrato button and an arrow button will bend the pitch up or down by a semitone.

Additional features include a built-in speaker, a headphone output jack that can also be used for line output, and a USB jack that can be used with a compatible power supply or to connect the NSX-39 to a computer.  With USB connected, you can access some web-based apps that will allow you to edit the instrument's vocabulary so that you can make the instrument sing lyrics to just about any Japanese-language song. 

The NSX-39 can also be used as a MIDI playback device. Input to MIDI channel 1 will play the voice synthesizer. Channels 2 through 16 are General MIDI compatible, with all the standard 128 instrument voices and drums. So, with MIDI sequencing software or a MIDI file player, you can have the NSX-39 sing lead vocals and perform the sounds of a backing band. It's kind of fun and it sounds better than I expected. Here is an example MP3 recording of an aria from "The Magic Flute" I made using a MIDI file I found online:

The NSX-39 is playing the vocal line with just the "O" vowel sound. There is also a way to use MIDI to make adjustments to the NSX-1 chip's digital signal processing effects, but I haven't dug into those capabilities yet.

The Gakken SNX-39 Pocket Miku comes with a 16-page owner's manual with an article about the history of voice synthesis. It's all in Japanese, but I found an English-language version on the web.

The NSX-39 "Pocket Miku" sells for around $70 new, or you can pick up a used one on eBay for as little as about $40. (If you follow the link and make a purchase on eBay, a small sales commission will go to the Stylophone Museum.)