Greetings!
I finally had some time to explore my Linnstrument I've aquired this year. Used unit in mint condition, I've checked for any damages by myself through disassembly and did a full calibration (tightening the screws the way Roger Linn recommended it).
While setting up some patches and playing around I've noticed the following phenomenon:
When doing slower pitch slides the pressure/Z-axis value is kinda shaky while not using heavy finger pressure. It almost has a step-like characteristic when doing slower slides. The pressure seems to also vary when moving the finger whithin a cell (without tilting the finger). This uneveness becomes audible when I'm using patches where the pressure for example modulates the amplitude of a synth by 100% (pressure > volume).
I expect this is due to the characteristics of the sensor and cannot be changed (no letdown for me since there are workarounds like bending via low row), but I still have to ask out of curiosity if there is any hidden setting I've been missing that does some pressure smoothing during the slides or if (any of the developers is reading this) there was an actual attempt to include such a feature but it was scrapped because of unreliability. Or are there some playing techniques I shall look into?
My 2 cents on the Linnstrument: Exceptional controller, also a prime example of how an instrument should be designed if it is meant to be a standalone MIDI device.
Screenshots representing recorded MIDI data:
Some background info:
While the Linnstrument was still in developement I've tried multiple times to create a working prototype with identical functionality/layout, worrying the Linnstrument will never be released or unaffordable/unavailable in my country (Germany). Never got a prototype done that is fully playable without issues, but managed to make the individual features work. The phenomena described above was also quite an issue. I've somehow managed to tame the uneveness by making the sensor slowly chase the current pressure value (almost freezing it) whenever a slide was about to happen or is happening. This kinda worked, but thanks to the rapid change in pressure during the cell transitions where the finger is near the sensor edge the frozen value would often make a massive value jump, not representing the actual pressure during the slide.
Pressure (z-axis) consistency during pitch slides
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- KVRer
- Topic Starter
- 15 posts since 8 May, 2019
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- KVRAF
- 1550 posts since 2 Apr, 2015
How are you sure it is not your finger pressure that is changing?
For between notes I could understand because of the indentations, but on a single note?
For between notes I could understand because of the indentations, but on a single note?
Bitwig, against the constitution.
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- KVRAF
- 2487 posts since 8 Jun, 2010
- Roger Linn Design
Hi Fleeesch,
Thank you for owning a LinnStrument. In answer to your question, LinnStrument's internal touch sensor has regions of touch-sensing directly below each of the 8 rows and 25 playing columns, with a 1mm gap between the columns. When you slide your finger left or right across columns, we overcome this gap by smoothing the sent pressure messages. However, our time-based smoothing doesn't work as well if you slide very slowly. Looking at your graph, it appears that your slide occurred over a two-measure duration, which even at a fast tempo is a very slow slide, so it didn't smooth the pressure as it would with faster slides that are more common to expressive musical gestures. I feel that our smoothing algorithm works well for LinnStrument's intended purpose of performing expressive musical gestures, but if you needs including performing very slow finger slides, it won't work as well and may not meet your needs.
Thank you for owning a LinnStrument. In answer to your question, LinnStrument's internal touch sensor has regions of touch-sensing directly below each of the 8 rows and 25 playing columns, with a 1mm gap between the columns. When you slide your finger left or right across columns, we overcome this gap by smoothing the sent pressure messages. However, our time-based smoothing doesn't work as well if you slide very slowly. Looking at your graph, it appears that your slide occurred over a two-measure duration, which even at a fast tempo is a very slow slide, so it didn't smooth the pressure as it would with faster slides that are more common to expressive musical gestures. I feel that our smoothing algorithm works well for LinnStrument's intended purpose of performing expressive musical gestures, but if you needs including performing very slow finger slides, it won't work as well and may not meet your needs.
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- KVRer
- Topic Starter
- 15 posts since 8 May, 2019
Wow, that was fast. Thanks for the insight, Roger!
Kept myself from taking the Linnstrument further apart to get a closer look at the details, no way I could do that without damaging the sensor sheets. It's amazing to finally have a working MPE controller right at my fingertips.
I was also quite suprised about the construction. Looks like the mainboard carries all the finger pressure by itself with the LED board screwed underneath giving it additional (or the required) stability. I was quite afraid after the assembly to put all that weight on the board when trying too play loud notes with vibrato, but since nobody here ever mentioned splitting their playing surface in two while jamming there seems to be no reason to worry.
@BobDog
There is definitly some natural finger pressure variation during the slide since the pressure data I posted has a wavy character. The issue I had were the regular spaced spikes in the channel pressure data appearing with every transition from one cell to another. Take a look at the close-up (bottom screenshot).
Kept myself from taking the Linnstrument further apart to get a closer look at the details, no way I could do that without damaging the sensor sheets. It's amazing to finally have a working MPE controller right at my fingertips.
I was also quite suprised about the construction. Looks like the mainboard carries all the finger pressure by itself with the LED board screwed underneath giving it additional (or the required) stability. I was quite afraid after the assembly to put all that weight on the board when trying too play loud notes with vibrato, but since nobody here ever mentioned splitting their playing surface in two while jamming there seems to be no reason to worry.
@BobDog
There is definitly some natural finger pressure variation during the slide since the pressure data I posted has a wavy character. The issue I had were the regular spaced spikes in the channel pressure data appearing with every transition from one cell to another. Take a look at the close-up (bottom screenshot).
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- KVRAF
- 2487 posts since 8 Jun, 2010
- Roger Linn Design
Hi Fleesch,
Taking it apart won't hurt it because I designed it for easy parts replacement by the owner. But I wouldn't recommend detaching the touch sensor sheet from the circuit board.
Also, when you reassemble it, keep in mind that the top panel screws shouldn't be too loose or too tight, because they also hold the sensor's contacts against the circuit board. Here's the tightening rule, as stated on the FAQ page:
Loosen the screw, then while pressing with one hand on the top panel near the screw, turn the screwdriver clockwise with your other hand until the screw head is level with the top panel and you start to feel the increased resistance of the screw being fully seated in the hole. Then tighten an additional 1/4 turn only and no more.
And don't worry about the main circuit board taking hard playing pressure. It's extra thick at .093 inches and it doesn't bend across the 6-inch span of the chassis below.
Taking it apart won't hurt it because I designed it for easy parts replacement by the owner. But I wouldn't recommend detaching the touch sensor sheet from the circuit board.
Also, when you reassemble it, keep in mind that the top panel screws shouldn't be too loose or too tight, because they also hold the sensor's contacts against the circuit board. Here's the tightening rule, as stated on the FAQ page:
Loosen the screw, then while pressing with one hand on the top panel near the screw, turn the screwdriver clockwise with your other hand until the screw head is level with the top panel and you start to feel the increased resistance of the screw being fully seated in the hole. Then tighten an additional 1/4 turn only and no more.
And don't worry about the main circuit board taking hard playing pressure. It's extra thick at .093 inches and it doesn't bend across the 6-inch span of the chassis below.
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- KVRer
- Topic Starter
- 15 posts since 8 May, 2019
Thanks again, very helpful!
And there I was wondering why two columns were acting funky until I did the tightening process all over again.
It's kinda obvious, but I was quite confused about how there could be reliable conductivity with those senor sheet contacts. Pressure, of course. Makes sense.
And there I was wondering why two columns were acting funky until I did the tightening process all over again.
It's kinda obvious, but I was quite confused about how there could be reliable conductivity with those senor sheet contacts. Pressure, of course. Makes sense.
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- KVRist
- 171 posts since 10 May, 2018
<repeating-himself>
And THIS is why I use a LinnStrument with absolutely no trepidation at all. No other MPE device on the planet has this kind of fast and informative feedback loop (except maybe the Soundplane). Roger's probably sick of me singing his praises all the time, but if every other maker had this kind of back-and-forth, the MPE market would be way healthier.
</repeating-himself>
And THIS is why I use a LinnStrument with absolutely no trepidation at all. No other MPE device on the planet has this kind of fast and informative feedback loop (except maybe the Soundplane). Roger's probably sick of me singing his praises all the time, but if every other maker had this kind of back-and-forth, the MPE market would be way healthier.
</repeating-himself>
Mike Metlay, PhD (nuclear physics -- no, seriously!)
listen to me: Mr. Spiral | join the fam: RadioSpiral | my gig: Atomic Words LLC (coming soon)
listen to me: Mr. Spiral | join the fam: RadioSpiral | my gig: Atomic Words LLC (coming soon)
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- KVRAF
- 2487 posts since 8 Jun, 2010
- Roger Linn Design
I never get sick of praise. 
By the way, the reason for the screw tightness issue is that this allowed me to avoid using connectors for the top and bottoms of the sensor’s columns. Had I used such connectors, the margins above and below the playing surface would have needed to be about an inch wider. I preferred narrow margins around the playing surface. Instead of connectors, the screws hold the sensor’s column contacts against the PC board for electrical connection.
By the way, the reason for the screw tightness issue is that this allowed me to avoid using connectors for the top and bottoms of the sensor’s columns. Had I used such connectors, the margins above and below the playing surface would have needed to be about an inch wider. I preferred narrow margins around the playing surface. Instead of connectors, the screws hold the sensor’s column contacts against the PC board for electrical connection.
