metal 3 zone bell sensitivity

[Mr_Bluesguy]

I need some insight into an issue I'm having with a 20" LV ride cymbal. I have it configured as a metal 3 zone with the bell being piezo activated. The edge and bow zones work very well but the bell zone won't activate without a HUGE hit directly over the piezo, even with threshold set to nearly zero. The screenshot should provide all of the particulars of the configuration. I eliminated the piezo being the source of the problem by checking it on an o-scope at the tip contact of the plug that connects to the edrumin. Its a solid 5v peak with a robust hit. As a double check, I plugged the bell piezo into a channel not adjacent to the piezo/switch channel and configured as a mono input 2 zone metal cym. It has plenty of sensitivity in that configuration. What am I missing here? I'm using V 2.3.1.21

edrum screenshot bell sens.jpg (63.73 KiB) Viewed 2128 times

[Rob]

It's been a while since I looked at that code, but I'm pretty sure the Bell Thresh control is just comparing the voltage on the bell piezo compared to the voltage on the bow piezo. I'll have a look this afternoon and give you more details.

[Mr_Bluesguy]

Hi Rob. Just wanted to circle back and see if you've had a chance to look into the bell trigger sensitivity issue. I know things get hectic and stuff falls through the cracks.... Thanks

[Rob]

I just had a look. To determine if a bell should be triggered eDRUMin computes the ratio of the bell signal strength / bow signal strength. This number needs to be at least 0.5. So if your bell piezo isn't at least half as strong as your bow signal, you won't be able to trigger a bell.

[Mr_Bluesguy]

Ok, thanks for the clarification. I'll do some more investigating

[Mr_Bluesguy]

So, I have a question.. would it be possible (and/or useful) to have a control function that would allow a small range of adjustment on the bell to bow signal ratio required for a bell trigger? Or is it more complicated than that, with complex interplay with other factors?
The reason I'm inquiring is two-fold. Reason 1: (I'm assuming that the 50% ratio applies to both two zone metal and three zone metal cymbals) On the two zone mode for my 20" ride cymbal with my best optimization of thresholds, etc., I get nice separation of bell and bow 90% of the time. The other 10% is when a bow strike will randomly trigger a bell sound, almost as if the threshold is in a gray zone and nudging it to one side or the other might improve the false bell triggering. Reason 2: In the three zone mode, with an edge switch and bell piezo, I'm still struggling to get the bell to trigger at all. I've been comparing the signal levels relative to each other on a 2 channel o-scope. There's roughly a 2 to 1 bow to bell ratio, but its close and kind of gets lost in the noise. I've been trying various piezo configurations and locations without much effect, and again, being able to slightly alter that threshold level might lift things out of the noise. My understanding of the trigger algorithm may be faulty, or maybe something entirely different is going on, but at this point, I've still no bell. Any other ideas?

[Rob]

For your 3 zone cymbal, put a 30k resistor in series with your bow piezo and I suspect it'll trigger the bell just fine.

[Mr_Bluesguy]

OK, I'll check it out. Thanx

[Ronyd]

OK, I'll check it out. Thanx

Hi, how did you make out with the 30k resistor?

[Mr_Bluesguy]

Haven't tried yet. Going to try a different trigger configuration or two first. I'll let you know