The circuit converts the signal from the aux piezo to a switch signal. With roland modules, even pressing the aux piezo and thereby flexing it activates the switch and sends aftertouch midi signal to create choke.dmitri wrote:1. The circuit you showed suggests that the pad is actually piezo/piezo. How can you do choke with it?
I'm not sure I understood what you suggested, but I think I understand how cymbals are implemented with megadrum as compared to roland.dmitri wrote:2. With this piezo/piezo pad and this circuit you can simulate a switch on the rim/edge input by puting a pull-up resistor of 1k-10k value between the input and +5V. But again, choke won't work since it is not a real switch.
I tried using my snare (piezo/piezo design) as the pad for my cymbal input in megadrum and set it to dual head piezo/piezo. I can get both sounds of bow and edge but no choke. Then I set it to dual head piezo/switch and I can get both sounds of bow and edge with switch. Please correct me if I'm wrong in concluding that megadrum accepts dual zone cymbals only with piezo/piezo design i.e. the edge only receives signal from a piezo and not a switch. The switch is only for choking and not sending signal for the edge to sound.
With Roland modules, the cymbal inputs are designed to accept piezo signal for the head(bow) and switch signal for both the rim(edge) and choke. So only 1 piezo is needed with roland modules which is logical if you need isolation between zone signals. When you hit the head(bow) only the head piezo is activated and the module knows it should send a note for the bow sound. if you hit the rim(edge) both the head piezo and the rim switch is activated and knows it should send a note for the edge sound. But if you only press the switch only the switch is activated and the module will send a note for aftertouch for choke sound.
With a piezo/piezo cymbal design, it will be hard to get isolation between the two zones since both piezos will be activated whenever the cymbal is hit.
I hope I made sense in this long ramble and did not irritate anyone. Maybe we could use this idea to further improve megadrum. Heck, if this can be implemented then so much the better.
Btw, Dmitri, I remember you said you'd put a crosstalk setting for each input. Is that plan still on the way?
Thanks again for this very nice project!