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Q: How to determine if a pad is hot, cool, just right

PostPosted: Sat Jul 25, 2015 5:34 pm
by Jorns Bergenson
I've read so many posts, but I still don't understand what parameters makes a pad "too hot" or "too cool" for MegaDrum. Which leads to my question: What is a fool-proof method for determining if the output level from a trigger is optimal for Megadrum?

-- Is it as simple as using an oscilloscope to determine the peak voltage produced when striking the pad "very hard" in the sweet spot?
-- Is there a method to determine if a pad is "too hot" by using MDM? For instance, what about setting Gain to 1, turn AutoHighLevel on, and striking the drum very hard. Then if the HighLevel is above some value, then the trigger is "too hot". The positional board would probably need to be disconnected for this to work.
-- Other than peak voltage, how important is the the "quality" of the waveform, such as having smooth peaks?
-- What problems does a "too hot" signal cause? Is it clipping due to the signal falling outside of the working voltage range of the multiplexer ICs, the ADC inputs or the op-amps on the positional sensing board?
-- What is the optimal decay for the waveform to avoid problems with re-triggering?

Thanks for any help that you can provide.
- Jorns

Re: Q: How to determine if a pad is hot, cool, just right

PostPosted: Sat Jul 25, 2015 5:57 pm
by dmitri
Jorns Bergenson wrote:I've read so many posts, but I still don't understand what parameters makes a pad "too hot" or "too cool" for MegaDrum. Which leads to my question: What is a fool-proof method for determining if the output level from a trigger is optimal for Megadrum?

-- Is it as simple as using an oscilloscope to determine the peak voltage produced when striking the pad "very hard" in the sweet spot?

You don't need an oscilloscope for that.

-- Is there a method to determine if a pad is "too hot" by using MDM? For instance, what about setting Gain to 1, turn AutoHighLevel on, and striking the drum very hard. Then if the HighLevel is above some value, then the trigger is "too hot". The positional board would probably need to be disconnected for this to work.

If with Gain 0 you still get HighLevel above ~900-950 then a pad is too "hot" and you may need to reduce piezo signal level with a voltage divider. Inputs with precision rectifiers (inputs 4,6,8,10 and 12) of the Positional sensing addon are alread "cooled" down. Otherwise it is irrelevant if the Positional sensing addon is connected or not.
Also read HighLevel description in http://www.megadrum.info/content/pads-settings
-- Other than peak voltage, how important is the the "quality" of the waveform, such as having smooth peaks?

"Quality" of the waveform doesn't matter as long as peak levels of signals are consist in relation to the strength of hits.
-- What problems does a "too hot" signal cause? Is it clipping due to the signal falling outside of the working voltage range of the multiplexer ICs, the ADC inputs or the op-amps on the positional sensing board?

Exactly. As a result you lose dynamics above clipping level.
-- What is the optimal decay for the waveform to avoid problems with re-triggering?

As long as it subsides monotonically it is optimal.

Re: Q: How to determine if a pad is hot, cool, just right

PostPosted: Sat Jul 25, 2015 8:04 pm
by Jorns Bergenson
Thank you Dmitri for your quick response.