[sdiy] MIDI velocity

[Terry Shultz]

Just in key of c and all will be equal

Heh heh

Terry

Sent from my iPhone

> On Apr 24, 2016, at 2:04 PM, P Maddox <yo at vacoloco.net> wrote:
> 
> Yup, same here...
> 
> black keys seem 'quicker' than the white keys
> 
>> On 24 April 2016 at 18:04, Amos <controlvoltage at gmail.com> wrote:
>> I'm curious to hear if others have noted significantly different switch timing (relative to actual played velocity) for black keys versus white keys, on those Fatar keybeds.  
>> 
>> My experience is that the black keys seem "hotter" than the white keys, enough that I have to use separate curves for black versus white to get consistent-feeling MIDI velocity output.  I chalked it up to geometry and physics and went about my way, but I didn't notice any similar comments so far in this thread so I thought I'd ask if it was just me experiencing this...
>> 
>> -Amos
>> 
>>> On Wed, Apr 13, 2016 at 9:24 PM, <rsdio at audiobanshee.com> wrote:
>>> 
>>> On Apr 13, 2016, at 12:20 PM, Neil Johnson <neil.johnson71 at gmail.com> wrote:
>>> > I wrote:
>>> >
>>> >> About 7 years ago when I was writing the keyboard scanning code for a
>>> >> Siel Opera 6 I had a simple scheme for scanning and measuring play and
>>> >> release velocity (not many folks seem to know about release velocity
>>> >> although some synthesizers do recognise it).
>>> >>
>>> >> Using an Atmel ATMega8 scanning the entire keyboard every 1ms I run
>>> >> 4-state state machine for each key, where the states are UP,
>>> >> GOINGDOWN, DOWN, GOINGUP, and an 8-bit counter for each key.
>>> >> Debouncing is handled by the algorithm rather than a separate
>>> >> debouncing step.  With the right encoding of the states you can do
>>> >> most of the testing and state transitions using btiwise operations, 8
>>> >> keys at a time (on a 32-bit processor you could do 32 keys at a time).
>>> >>
>>> >> I'll try and dig out the code and sling it up on github sometime.
>>> >> It's all in C, no assembler required.
>>> >
>>> > Found it, and hosted up on github:
>>> >
>>> > https://github.com/nejohnson/kbdscan
>>> >
>>> > The keyboard scanner talks to a 74LS154 on the keyboard assembly, and
>>> > generates key on and off events with associated velocities.  There's
>>> > also code for reading some analogue inputs and a footswitch, but
>>> > that's not important right now.
>>> 
>>> Thanks for sharing this!
>>> 
>>> I was going to suggest that having the 'LS154 on the keyboard assembly is a great design choice, because that allows a simple, 14-pin connector, but then I realized you probably were stuck with that choice because of how the Siel Opera 6 was designed. Sure enough, looking at the schematic I see 8 row bits, 4 column address bits, power and ground. (feel free to swap the row and column nomenclature as you prefer - Roland seems to use the opposite terms)
>>> 
>>> Brian
>>> 
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at dropmix.xs4all.nl
>>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>> 
>> 
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20160424/e73a6306/attachment.htm>