Black Key Velocity Problem

Tips and techniques for Minimoog Analog Synthesizers
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markwilkins
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Black Key Velocity Problem

Post by markwilkins » Sat Feb 18, 2023 12:03 am

I have received one of the 2022 Model D units and am loving it. The synth is astonishingly fun to play.

There is some strangeness in the velocity output from the black keys that I am puzzling over (the black keys on the synth; not the band ... although I do play their music rather loudly at times). I connected the velocity control output to the loudness control input via a patch cable. It works perfectly with the white keys on the synth keyboard: Playing softly (slow press) results in quiet tones; pressing fast results in louder tones. However, the black keys all play as if the patch cable was not plugged in (loud with no variation).

I tested a bit by changing the patch cable to the Filter input. Again, the white keys work as expected. The black keys have no variation; their affect on the filter is the same regardless of how slow/fast I play those keys.

When I play the Model D using an external keyboard via MIDI, the velocity control works flawlessly for both white keys and black keys. So the problem seems to be associated with the physical keyboard.

I'm confident this is not the intended behavior. My google searches have not uncovered anything, so I'm kind of thinking the problem is not a general widespread issue with these units but is specific to mine. Any thoughts on possible fixes?

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markwilkins
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Re: Black Key Velocity Problem

Post by markwilkins » Mon Feb 20, 2023 1:02 pm

I have been "debugging" this a little bit more trying to understand what is going on. I tried a few different things:
  • I sent the MIDI out from the model D to another keyboard playing a sampled Rhodes patch. I then played a chromatic scale on the model D. The white keys played the Rhodes sound at a mid level volume corresponding to my touch. The black keys sent (apparently) a 127 value and made the Rhodes patch scream. Admittedly, a full volume Rhodes scream sounds fantastic ... but not in that context.
  • I then unplugged the patch cable from the velocity control output and repeated the scale. No change (soft white keys, screaming loud black keys)
  • I selected the soft velocity curve on the model D (turn it off, hold the c minor chord, turn it on). Repeated the scales and ... it played perfectly. Hmmm; promising!
  • Selected the hard velocity curve. Repeat experiment. Screaming black keys again.
  • Select medium velocity curve. Partial screaming black keys (but mostly screaming).
  • Selected the soft curve and plugged in the patch cable again. Played chromatic scale on the model D and listened to the model D audio and it was lovely; very smooth and none of the original bad behavior.
  • Selected the hard velocity curve. Exhibited bad behavior.
  • Switched back and forth a few times between the velocity curves. And then all the curves seemed to start working better.
So this is all very encouraging. I can live with using the soft velocity curve if that is what it takes. But it is still kind of baffling. Why does it now seem to work with all velocity curves? Am I not successfully choosing the hard curve? Did the keyboard just start working better (some mechanical weirdness)? Is it a firmware issue in the Fatar?

There is still one odd thing that seems to occur more with (but not limited to) the hard velocity curve. Playing chromatic scales sometimes seems to fail to trigger a black key at all. Just silence. It is possible it is just playing quietly and maybe my fingers just did not play well. But it seems fairly consistent. I am going to send the MIDI out to my DAW and record the notes that way and then I can get a better picture of the relative volumes and be able to tell if the keys are failing to trigger sometimes or if it is just really soft. I will report back with those findings.

P.S. Man this thing sounds so wonderful. Wow wow wow. I love the sound.

sdwillingham
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Re: Black Key Velocity Problem

Post by sdwillingham » Tue Feb 21, 2023 12:45 pm

Good debugging work. (For reference, I can confirm that my 2022-RI does not have this behavior; the black key velocity is consistent with white keys.)

I recommend that you contact Moog support about this. It sounds to me like maybe some calibration procedure was not done correctly on your unit. The velocity response is all done by calculation in the keyboard processor.

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markwilkins
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Re: Black Key Velocity Problem

Post by markwilkins » Tue Feb 21, 2023 11:10 pm

Thank you for the response and for letting me know that your key velocity is consistent. That was one of the main things I was hoping to learn from this post. And good advice too: I contacted Moog support and have heard back from them. They had me perform a factory reset (which seems a good test; I should have thought of that). However, it does not change the behavior. So I sent a couple videos of the behavior and a few more details. I imagine we will get it sorted out. I hope I don't have to trade it in. I have serial number 511, which is pretty cool from a programmer standpoint. I would hate to give that up. Not a Mersenne prime, but ... still. A good number.

Mark

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markwilkins
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Re: Black Key Velocity Problem

Post by markwilkins » Wed Feb 22, 2023 11:57 pm

As I mentioned, I contacted Moog support and have been conversing with a support engineer. It's pretty funny being on this side of the support problem. I'm a programmer and, thus, have been indirectly involved with support issues over many years. The default stance from the developer/producer/seller is always, "Our product is perfect. What are you doing wrong?" I'm totally guilty of that. It is a form of the "Six Steps of Debugging"; if you are a nerd person, you will get that. Although, I'm pretty sure this is not quite the same. It definitely sounds like the problem is unique to my specific Model D and not a generic problem, which is good.

But it is an interesting problem. Why do the black keys play different velocities than the white keys under certain circumstances?

As I mentioned earlier, I said I would gather data by sending MIDI to the DAW. I did that and am finding it to basically be what I expected. The black keys send value 127 for the velocity a lot of the time. I was going to upload a couple of screen shots, but I do not see any option to upload images/files on this forum. Maybe my eyes are not working correctly. I guess I'll just describe it: For one test, I played a white key "softly" and then played a black key at an equivalent soft level and then back again. Alternating. The velocity values shown in the DAW for the white keys were 1, 2, 21. The black key velocities were 127, 127, 127. It totally matches what my ears are hearing.

I will keep you posted on the forthcoming process! - for the 3 people breathlessly watching this thread :)

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markwilkins
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Re: Black Key Velocity Problem

Post by markwilkins » Thu Feb 23, 2023 11:19 pm

The support rep I have been working with does agree there is a problem with the keyboard. While I would have preferred it to be some kind of stupid user error on my part, I'm relieved not to have to send more videos and pictures of settings and velocities and such.

But before I have to send it back for repairs or return it to Sweetwater through whom I made the purchase, I can't help but think it should be possible to remove a couple of panels and get to the connections to the Fatar keybed. I am probably totally wrong, but it "seems" like the issue must be associated with the Fatar mechanics somewhere. The fact that the velocity output to other MIDI devices is totally out of whack suggests (to me and my naive brain) that it is not the "synth proper" with the issue. Maybe there are two ribbon outputs from the Fatar (one for black keys and one for white keys)? And maybe the black key ribbon is loose?

Does anyone have schematics (or pics) of the inside of one of these?

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VCO
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Re: Black Key Velocity Problem

Post by VCO » Fri Feb 24, 2023 1:27 am

Does your aftertouch work correctly? It’s possible that the ribbon connections are acting intermittent since it might be not making a complete connection.

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markwilkins
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Re: Black Key Velocity Problem

Post by markwilkins » Fri Feb 24, 2023 10:29 am

VCO wrote: Fri Feb 24, 2023 1:27 am Does your aftertouch work correctly? It’s possible that the ribbon connections are acting intermittent since it might be not making a complete connection.
The aftertouch does seem to be fine. It works like others have described in the other thread going on about aftertouch. It is kind of an on or off scenario. The behavior between black keys and white keys is the same.

sdwillingham
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Re: Black Key Velocity Problem

Post by sdwillingham » Fri Feb 24, 2023 11:21 am

It is easy to take a look at the keyboard controller PCB. Just remove the 8 (?) screws on the bottom panel of the Mini and lift off the panel. The keyboard PCB is right there in the center. There are helpful photos of the 2016RI at https://gearspace.com/board/electronic- ... d-127.html.

The 2022RI has the same physical setup. The left-hand controller board is completely new for ‘22, but the keyboard controller has a silkscreen dated from 2016. The ribbon connects to the left-hand controller, passing signals such as MIDI, modulation, pitch-bend, AT voltages (possibly pitch CV and gates too, but I don’t know for certain).

Since the LH controller does not separately connect to the keyboard (except for the AT sensor), I guess there must be a connector plugging-in beneath this card for the keyboard switch matrix. I don’t see why the matrix connection would be segregated for black and white keys; that just seems to complicate things. I still very much suspect a firmware issue. Velocity value is derived from the time difference between two switch contacts on each key. Since the black keys are physically shorter, I would imagine that the computed velocity must use a calibration constant to adjust the relative key sensitivities to feel right. [Just my guess.]

Good luck!

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markwilkins
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Re: Black Key Velocity Problem

Post by markwilkins » Fri Feb 24, 2023 11:20 pm

Thanks for the link with the pics; this is good reference information. I don’t see anything in those that I am smart enough to consider fiddling with for this issue. Given that it is new and the risk of me breaking something is non-zero, my current plan is just to send it in and let the knowledgeable people fix it. I’m betting it will be something very simple. Hopefully I will be informed of what it is. It makes for an interesting thread if nothing else.

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ummagumma
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Re: Black Key Velocity Problem

Post by ummagumma » Sat Feb 25, 2023 3:25 am

Sucks it's not just a simple loose plug etc.

Good luck!

-->did you try turning it on & off again?

:)

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markwilkins
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Re: Black Key Velocity Problem

Post by markwilkins » Thu Mar 16, 2023 11:15 pm

Update on this: I ended up sending the unit to Moog, and they fixed it! The problem did indeed repro for them. The solution was "... flash the Eprom, re-install the firmware, and then re-do the CV calibrations". I had done a firmware reinstall during the "debugging" process with no effect. So I'm guessing it was one or both of the first and third of those (eprom, cv calibrations). In any case, it is working perfectly now!

So aside from the "anxiety" of sending the keyboard (that I had absolutely fallen in love with in a few short days) on a four and a half thousand mile journey in a cardboard box, it has been great experience.

It is interesting to me to observe how I have become emotionally attached to this particular instrument in such a short time. The shipping anxiety made me see this. It seems to me there is an aspect to the musicality and craftsmanship of this synthesizer that makes it different from some mass-produced instrument. The violin people will hate me, but I keep thinking of this synth as being my own secret Stradivarius.

sdwillingham
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Re: Black Key Velocity Problem

Post by sdwillingham » Mon Mar 20, 2023 1:20 am

Great you got this sorted with Moog. I completely understand your feelings about the Model D as a personal, relatable instrument.

I hope Moog will publish the calibration procedure sometime. I’m kind of concerned, since the centering and range of the nice upgraded pitch bend (and the operation of the new MIDI capable modulation wheel) are dependent on firmware calibrations. If those potentiometers need to be replaced, the calibrations will need to be updated, and I don’t want to have to send the instrument away for such simple services.

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