False Trigger Suppression Algorithm Single Piezo vs. Dual

[maru_engineering]

Hello Dmitri

I think that in the current FalseTrSupp algorithm there might be some room for improvement...
Here is what I found out: while working on a new snare pad and fighting to achieve the lowest values for DynLevel and DynTime without false hits, the output jack became partially disconnected (basically I lost the rim signal) without me noticing...
But I noticed that all the false hits from the Head vanished...
The same is happening if I change the Pad Setting to Single Piezo and Disable the Rim...
So, with Single Piezo Setting I get perfect triggering with low suppression values; with Dual Piezo Setting it feels like there is a "leak" of the rim signal in the head signal...

What do you think, Dmitri?

[maru_engineering]

I also, just for test, left the Rim enabled on the pad while in Single Piezo mode... Of course I get overlapping signal from the Rim, because the per pad crosstalk is not enabled in Single Piezo mode, but the Head triggering is still ok, no double notes on the Head...

And as a side note, when I fed the same signal into both Head and Rim inputs (also just for test), Megadrum crashed

[dmitri]

When you set a dual zone piezo/piezo pad you have to adjust MidPoint for a balance between Head and Rim. If you also want to use crosstick then you also need to adjust MidPointWidth. And of course these settings will work properly only if both Head and Rim have HighLevel set correctly. I also think you have DynTime and DynLevel are both set too low but I might be wrong (e.g. you pad produces very clean signal with almost no after hit triggering/vibration.

[ignotus]

@maru_engineering:

Have you tried raising the 'noise filter' setting? It worked wonders for me and completely got rid of double hits.

[maru_engineering]

Thank you both for your answers; I will try to increase the Noise Filter Lever but my point is that the trigger of the Head input is fine with the current settings as long as the Rim input signal is suppressed...

If anyone hase time, could you test something for me?
So, I'm using an A to E 14" Snare with a DIY trigger inspired from R-Drums RTS II snare drum trigger system and using Drum-Tec Real Feel Triple Mesh Head.
If somebody uses something similar (14" mesh pad) could you try to replace the "stereo" cable from the pad to the module with a "mono" cable and then try to lower the Retrigger Mask, Dyn Level, Dyn Time to see if you can get lower values without double triggering? If yes, could you swap the mono cable to the original stereo and see how the Head triggering behaves?
I expect that you will get false triggers on the Head input when the Rim signal is present (at least that's what is happening to me )

Of course my pad is not perfect; if I use the AltTrigSupprAlg (the old one?) I get double triggers even without the Rim Signal present... I'm just baffled because I don't understand why the Rim signal is causing the Head input to double trigger...

[maru_engineering]

Hello,

I did some more tests today... I concluded that the Rim/Edge Threshold is influencing the Head/Bow Response...
If I lower the Rim/Edge Threshold I get double Triggering in the corresponding Head/Bow input
Is this to be expected or is there something wrong on my side?

[dmitri]

Set DynLevel to 15 and DynTime to 60 on both head and rim. Still having false double triggering after that?

[maru_engineering]

Hi Dmitri,

It's better but the doubles are still there...

[dmitri]

1. Since it is a mesh pad, it produces signals with quite long half-waves. A 12" mesh type pad typically produces at least 4ms half-waves and it requires MinScan set to at least 40. A 14" mesh type pad will most likely require MinScan at least 60.
2. You set Curve to Custom16 so it is impossible to judge relative strength of signals in double triggering. Set it to unmodified LinearCustom1.

Also, judging by the MIDI Log, it looks like you may have excessive pad "ringing".
What sort of mechanical setup/tuning did you do on the pad itself?

[maru_engineering]

Hi Dmitri,

Here I used the unmodified LinearCustom1 for both Head and Rim inputs. I also set the Head to Single Piezo and the threshold of the Rim very low to reveal the relation between Head am Rim signals.