I have 3 instruments in my mind inspire me.
Nyckelharpa - keyed fiddle -
Surbahar
Clavichord

What do you think ? How we can get these designs together on a bass.
I think keys can be used to get sustain from a single note which produce until 3 or more notes. Keys can be put on neck for to be pulled.
Surbahar can be used to make longer scale -1 meters - and for secondory strings which can be silenced.
Clavichord concept can be used for the removable keys under the neck.
Curvilinear space frame and frets ... , microtonal fretboard , robotic arm and leg rest. All produced from pu foam.

Best ,

Mustafa Umut Sarac

Interesting. You've got to keep in mind that a bass string has a great deal of energy associated with its motion. Because of this, anything brought into contact with it and intended to act as the "bridge" or "witness point" must be both stiff enough and massive enough to sufficiently reflect back the string energy, rather than absorb it, in order to allow for any sustain at all.

For example, the nyckelharpa has higher pitched strings, and furthermore, it is bowed, so it does not have to have any real sustain, since the bow is constantly adding excitation.

In comparison to the clavichord, the heavy and energetic bass string would require a very stiff key mechanism, with a stiff, heavy tangent.

Plus, is it really a bass guitar if you start adding a bunch of keys onto it? Don't get me wrong, I'm all for ingenuity and if you can get any of those to work, more power to you but I think that those ideas are sort of going a step backwards; the instrument works fine (mechanicism-wise) as it is.

How 'bout some pics? I don't have enough brain cells to take your words and create an image of your ideas in my head.

A clavichord bass/guitar kind of already exists... it's called the clavinet. As is the case with the clavinet, I think the sound would be very nasal.

A keyed surbahar, to me, seems counterintuitive. It would remove the ability to bend notes, which is the main way of playing surbahar. The nyckelharpa makes some sense, in that it makes playing a fiddle easier, because there are no intonation woes. But surbahar already has frets, so I think you would be losing a major performance ability for no real gain.

I think it was pilotjones who brought up an idea some time ago to have some nyckelharpa-like keys on a bass to solve the problem that, when you fret a note, you inherently put it out of tune. It seems to me that the key would need to operate both the lifting up of a fret, and also clamp down on the string in order to not deflect it. Personally, I'm comfortable with the job the bridge does of intonation, but these are interesting ideas.

I think it was pilotjones who brought up an idea some time ago to have some nyckelharpa-like keys on a bass to solve the problem that, when you fret a note, you inherently put it out of tune. It seems to me that the key would need to operate both the lifting up of a fret, and also clamp down on the string in order to not deflect it. Personally, I'm comfortable with the job the bridge does of intonation, but these are interesting ideas.Yeah, that was me. I didn't know at the time (nor did anyone else note it) that there was an actual instrument that did something similar.