Tag: Sensors

Eigenharp key resolution of 1 micron? Hmmmm

I read that the Eigenharp has a resolution of one micron as concerns its key positions. Thats about 8 times smaller than a human blood cell…hmmm, I’m pretty skeptical for a number of reasons. First a disclaimer, that my skepticism is not with the instrument itself, I think they may have really hit on something huge, but its not the one micron thing.

The instruments intrinsic value is not the wippy internal tech stuff, like one micron resolution or otherwise, but that it provides many magnitudes of greater usability as a computer music interface. Light bulbs have been coming on left and right for the last few days, despite having never played with one, nor even seen one other than online. What they have, imho is really a world changer (even if it is not a success, nor widely adopted, the Eigenharp blows far too many paradigms to be ignored no matter what happens). As they mention in the video, the QWERTY keyboard and mouse is for word processing, its not designed for music. It really is insane when one thinks about it a bit… typing and mousing for musical impression? This is why I believe the Eigenharp is a world changer. Thus, onto the issue at hand, one micron resolution.

First of all, no musician on this planet can hold to any level of absolute positioning anywhere ever close. Physiological issues like blood flow pulsation will more than throw a wrench into 1 micron positioning, to say nothing of ambient air flow, or even temperature variations. Notice the key word I used, absolute….

More likely, is a pseudo relative thing. Ie, the Eigenlabs folks created one or more massive absolute dead zones (probably based on semitones) during the initial measurements, such that absolute positioning is not a factor, and then after an initial measurement period, use the high resolution measurement as a delta value for purposes of artistic nuance. Dead zones would still provide capability to start out with a sharp or flat tone if desired, without requiring incredibly precise finger position for intonation if being sharp or flat initially was not the intent of the artist.

This of course assumes they are using technology capable of really resolving 1 micron of resolution. Thats where the second part of hmmm comes in. Magnetic measurements wont cut it, as simply changing position of the instrument will throw off nearly any type of magnetic sensor due to the earths field or surrounding metal or body effects. At least without some incredibly high tech physical or electronic shielding that is.

About the only type of sensing device to have that level of resolution, in a reasonably small package is optical interferometry. In a nutshell, you fire off a laser and have it reflect back on itself, such that an interference pattern is generated. Then, as an object moves, so will the interference pattern, and as such one can detect incredibly small movements, in most cases well under a micron. Philips was working on this some years back with the PL2020, but it appears that parts data went blank, although they still have some marketing stuff available on their website.

Another possibility, is that the 1 micron thing is just marketing hype. For example, if you set maximum XYZ key travel at 0.080″, and digitize it at 12 bits resolution, toss the lsb, and you will find the output has a resolution of 1 micron. Such a sample is likely pretty noisey, drifts like all get out, and is pretty useless, but some marketing guy might have fun with it.

Either way, I find the instrument fascinating… Too bad I dont have a kazillion dollars to get one. About the only thing I might do, is resurrect some of my old notes on wind instrument design. It might be pretty cool to look at such interfaces once again.