Master Sensitivity Pot?

[ohawker]

I have noticed that drummers seem to vary greatly in sensitivity, i.e. some, when asked to play quieter, will, and some just don't understand the idea! Anyway, I am building MegaDrum with MAX2558's, so overspilling may be a problem! What I thought: could I put a pot between the ground of the piezos and actual ground, for the sake of controlling the master sensitivity of the trigger?

I could be talking a load of rubbish, but here's the idea:

piezo circuit.jpg

Would this work? If not, then could this be implemented in any way? This is a feature that could be very helpful, as I do not know how hot my pads are going to be! Any comments, criticisms, rolled eyes much appreciated!

ohawker

[Synthex]

Hot pads with MAX4558 can be a problem (overspilling).
I recommend the use of 74HC4851.

Your schematic is not good.
The pot must be set between IN and ground.

[Synthex]

Like that :

piezo_circuit.jpg

Or :

piezo_circuit_B.jpg

[ohawker]

This was the original idea, but 32 individual pots? Is there no other way other than using another type of MUXer?

[Synthex]

You can mount on every piezo a simple resistor (or two).

The attenuation of the signal will be constant for all the channels.
Then, no overspilling, and input gain can be adjusted by the Atmega on every channel.

[Synthex]

Like that :

piezo_circuit_2.jpg

Or :

piezo_circuit_2_B.jpg

[ohawker]

Ah ok good idea What value resistor should I be looking at? I have no real way of seeing how hot my pads are, especially seeing I haven't built them yet

[gabriel1712]

Sorry to revive this old thread, but the last question wasn't answered.

What value resistor should I be looking at?

Is there a way to tell how much each drum needs to be 'dimed'?

[dmitri]

When you set HighLvlAuto to Yes and then after hitting the pad a few times you see HighLevel is more then 900 then your pad is too hot.
The resistors can be between 10k-47k.

[gabriel1712]

Hmm... whacking the set, I'm getting readings well over 900 on several part. Looks like I'll be installing trimpots before I can get steady velocity readings. It should be easy on the mesh snare/toms but I'm wondering about the cymbals. Does Synthex' fine diagrams for trimpots on dual piezos also apply to the Piezo in a piezo/switch cymbal or should it be connected differently?

And would these 50k thingies do the job?