negative half-wave no hotspot?!

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negative half-wave no hotspot?!

Postby talrusher » Thu Dec 22, 2011 9:27 pm

i converted my pads by myself and tried a couple of triggering things...

i found out, that if my piezo produced a negative half-wave i had no hotspot like on positive wave.... but why?

regards
Here I stand in the falling rain
There is no joy inside these tears
I see the world through a twisted and bitter stare
To be where I have been... to see what I have seen
Is it a dream?
Or can I believe...
The memories will haunt me for evermore
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Re: negative half-wave no hotspot?!

Postby Sylv1co » Sat Dec 24, 2011 9:06 am

My two cents :

I think the module wait for the first positive half-wave to trigger a note.
If your first half-wave is negative it seems that when the head is pressed (by the hit of a stick), you have a negative half-wave, then when the head returns, you get the first positive wave. The foam under the piezo may absorb some energy and then the first positive half-wave is maybe less strong than the first negative half-wave.
I don't really know at which frequency a drum head could vibrate but at 500Hz, it take 2ms to get an entire wave, so if your module have to wait for the first positive half-wave, then it will wait for 1ms.
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Re: negative half-wave no hotspot?!

Postby talrusher » Sun Dec 25, 2011 4:39 am

noticed that roland uses in their pads or cymbals the negative halfwave. in my cy-5 the piezo is wired to produce a negative half wave, and thats produces on the trigger io less hotspotting, but what is with the megadrum?
should i wire my piezos that a negative or positive half wave come first? what is better for the megadrum module?
Here I stand in the falling rain
There is no joy inside these tears
I see the world through a twisted and bitter stare
To be where I have been... to see what I have seen
Is it a dream?
Or can I believe...
The memories will haunt me for evermore
talrusher
 
Posts: 111
Joined: Sun Nov 27, 2011 2:27 pm
Location: Germany

Re: negative half-wave no hotspot?!

Postby Maylord.war » Sun Jun 24, 2012 10:06 pm

If you put your cone/piezo on one side of the pad the hotspot disappear.

Btw you can decrease the distance of Foam cone from the mesh head, 0.8 - 1mm are good, in my pad i don't have any hotspot, i use the normal configuration (positive wire) .

Try to raise the Minscan value to 45-55 ( in my 12" tom works perfect ) , if you don't need the positional sensing use the negative wire to tip e positive to sleeve.

I use a similar roland cone with 35mm piezo, for better results i add in series a 10k resistor to "cold" the signals

Regards
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Re: negative half-wave no hotspot?!

Postby talrusher » Sun Jul 08, 2012 8:54 am

one 10k resistor? for my 35mm piezos i Need Minimum 200k and for my 27mm at least 159k...

can u make some Pictures of how do you mounted the piezo exactly to your pads? or describe it exactly plz...
Here I stand in the falling rain
There is no joy inside these tears
I see the world through a twisted and bitter stare
To be where I have been... to see what I have seen
Is it a dream?
Or can I believe...
The memories will haunt me for evermore
talrusher
 
Posts: 111
Joined: Sun Nov 27, 2011 2:27 pm
Location: Germany

Re: negative half-wave no hotspot?!

Postby Maylord.war » Fri Oct 05, 2012 3:25 pm

Hi Talusher

Sorry for the late reply.

Actually i don't have any pictures to show you how the cone is fitted.

Are you sure you need 200k resistor?

I mean 10k single resistor , perhaps you mean a 200k potentiometer ?

Wich "highlvl" and "gain" value do you have?
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