Positional Sensing with Jobeky Triggers and SD3

[Mylo]

I am trying to get positional sensing on my snare working with Jobeky's Adjustable Internal trigger and Superior Drummer 3.

With PS turned off center hits and sidestick works really well. When I turn on PS things work really well up to a point. It seems when I hit the center of the snare drum at full velocity SD3 wants to map the note 38 (center) to note 33 (edge).

I've attached several photos of the setup.

The first two show the snare and trigger placements within the snare drum.
The third is the MD settings with the Raw MIDI wrapped in blocks to show the output when I hit edge, mid-center and center.
The fourth is the Superior Drummer 3 MIDI analyzer showing that when I hit center with full velocity I get the edge articulation.

Any suggestions on what I'm missing here?

[jarosz]

On your screenshots you're showing different hits on MegaDrum MIDI Log and SD3 Analyzer, so it's not possible to understand what exactly is going on.

Maybe you're missing the fact, that positional sensing data is being held by MIDI CC16, and SD3 is mapping the sound correctly for the input it receives. It's not about MIDI Velocity (127), but CC Value (0 - Center, 127 - Edge - see my screenshot). I'm not able to tell why such value is being received by SD3, because of the reason pointed out above.

[Mylo]

So if I understand you correctly... the center hit should be sending CC - 0 but in this case it sends a CC - 127 so SD3 determines it should play the Edge articulation?

And without seeing what MD sends to SD3 on these incorrect hits it is not possible to ascertain what might be wrong.

I’ll see what if I can make that happen. But I’ve never had any success running both MDM and SD3 at the same time.

[jarosz]

So if I understand you correctly... the center hit should be sending CC - 0 but in this case it sends a CC - 127 so SD3 determines it should play the Edge articulation?

Yes.

But I’ve never had any success running both MDM and SD3 at the same time.

That's why MegaDrum has 2 USB-MIDI ports, the second one being actually a duplicate of the first (can be changed with MIDI2ForSySex option). In MDM FX settings you should pick up different port than in SD3.

[Mylo]

I identified in MDM the data that I think is suspect.

[dmitri]

If they were both centre hits then incorrect Positional sensing value can be due too various reasons:
1. Head mesh tension tuning.
2. Head piezo sensor<->mesh pressure.
3. Head piezo "ringing", i.e. long after hit vibration.
4. Too "hot" signal from the hardest hits.

All of the above can cause the signal from the head piezo to become distorted which throws positional sensing algorithm of course - a centre hit produces a signal which looks like a signal from near the rim and vice versa.

[Mylo]

The good news is that all these look addressable. I’ll give these a shot.

Can number 4 be tamed with adjustments to threshold, retrigger mask, and/or dyn level, dyn time? Or are more electronics needed?

[Mylo]

So I think I got this working.

1. I tried the head tuning... didn't work. Tried tightening and loosening.
2. I tried the head<->sensor pressure. The foam is barely touching the head now. But this didn't work either.
3. Couldn't really do much here.
4. Wasn't sure what to do here either.

What I did do was switch to Pos Level = 2, set Pos Low = 10 and set Pos High = 25. This seems to have done the trick.

[jarosz]

Positional sensing was easier to me to dial in using MegaDrum LCD display than MDM FX.

There is a setting "PositionalIn" which you should set (with MegaDrum buttons/encoders) to the input number which your snare is connected to. Then switch to PositionalLv setting and if it's 1, 2 or 3 then after hitting the snare you will see the calculated PS value of the hit for currently selected PS algorithm - this is valuable, because it's internal value which is then translated into MIDI CC. Going from the center to the edge you can figure out correct values of PositionalLow and PositionalHi for this particular pad and algorithm.

I would also advise to check whether it's not appropriate to increase MinScan value - your pad is quite large and larger mesh pads generate longer waves. Tightening head should make the wave shorter. IMO head should be tight to get accurate PS.

[Mylo]

Thanks jarosz. I’m happy to have it working. I’ll take your advice and try to get even better performance out of it.