This video says the strings will not sound until a string is fretted completing the electric current. So the ground current must be through the frets.
Here is the video of the guy strumming the strings that made me think not all strings were fretted. Seeing it a second time, he could have been pressing in while strumming like you do when pressing keys in a sweeping motion on a keyboard.
So Korrigan, you may be right about the Harpejii just being one big keyboard.
Kinda like having a 12,16 or 24 key keyboard and changing the pitch of each key with every fret you touch? That sounds a bit disappointing.
I may still make a stringed passive Harpejii clone in the future though. Isolation of each string from the others may be necessary or maybe splitting into groups. Sounds like a lot of experimentation fun.
I think that's how it works but it's more expressive than a keyboard because you can bend notes and create vibrato by wiggling your finger so it's not like a switch just making an electrical connection like a keyboard key. It's actually picking up the vibration of the sting and then processing it through effects.
So, yeah, I think it's a really cool instrument just not as simple to build as one might think when first seeing it. There's a lot of useful info in the patent though and it could certainly be done, it's just a matter of time and experimentation.
just a guess because i haven't researched this device , but i have seen it played before.
i think it has to do at least 2 things per string.
1 as you say a " keyboard" a matrix of horizontal frets and vertical strings. when a string is pressed to a fret its position can be " read" . here is where the MIDI side comes in i think they have a processor that reads which string is pressed and at what fret. assign it a MIDI note. you get on and off timings from how long the string is fretted.
2 i think they also have a " pickup " for each string. This is where they get the " envelope " your standard attack, sustain decay sort of thing... now this can be digitised and added to the MIDI information but also just be mixed together and amplified. maybe even mixed in with the MIDI sound.
i thought of this because sometimes it does sound like a straight stringed instrument, but at others like its an organ/ piano/synth.....
the clarity of the notes could certainly be a triggered MIDI sample etc...
all in all a very interesting instrument that probably took them years to perfect. and a fun thing to try to see if it can work out in pure analog form..
hmm, glue up 2 or 3 2x4's to make the body, ground the frets on bus 1, metal nut grounded on bus 2, footswitch to select between them so it acts like a sustain pedal for a piano/keyboard, each string has its own pickup with the ground side routing through the string to the fret or nut to the select switch to the jack's ground lug.
I'm also noticing that all the frets seem to have the same spacing between them and each string has the same scale length.
Bass scale is 30" to 36" for electric bass, Baritone Guitar scale is 27" to 29.5" for electric guitar and regular Guitar scale is 24.5" to 26.5".
To build a passive stringed version would need a fanned fret design and the 3 scales would need to be a close medium choice. Like 30" - 28" - 26". Or do 3 separate stepped fret design.
I'd probably do 3 separate columns since the bridges would probably be separate(1 adjustable bass bridge and 2 adjustable guitar bridges) and separate nuts. I could ground the 3 rod piezo's to each group of frets and switch between piezo and pickup or both. Not a fan of fanned frets anyway. ;)
This definitely won't work the same way, but it will be interesting. You could use it as a finger tapping instrument, Lap Steel Slide or Lap Style Strummer which will get even more interesting with the before mentioned effects.
The real fun would be tuning that thing. LOL
That's cool Andries. It probably sounds nice too, I love all those early analog synths from back in the day.