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A couple of questions about Poly aftertouch

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A couple of questions about Poly aftertouch

Postby Folderol » Tue Mar 10, 2020 5:59 pm

Is it normal (or even desirable) to have both channel and poly aftertouch available at the same time?

Also, should polyAT availability and type be the same over the whole instrument, specific to an incoming channel, or specific to a part/instrument regardless of what channel it is on?
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Re: A couple of questions about Poly aftertouch

Postby desmond » Tue Mar 10, 2020 6:31 pm

Folderol wrote:Is it normal (or even desirable) to have both channel and poly aftertouch available at the same time?

it's usually one or the other, as otherwise they will interfere, even if they are controlling different things (ie, pressing one key would always generate both channel and poly touch together).

Folderol wrote:Also, should polyAT availability and type be the same over the whole instrument, specific to an incoming channel, or specific to a part/instrument regardless of what channel it is on?

It's a channel message, so it should have a MIDI channel, and only apply to notes on that channel - unless your instrument doesn't care about the MIDI channel, like some plugins.
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Re: A couple of questions about Poly aftertouch

Postby Eddy Deegan » Tue Mar 10, 2020 9:07 pm

+1 to what Desmond said!

1) Poly or Channel, not both
2) PolyAT is per-Voice per-Channel

:D
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Re: A couple of questions about Poly aftertouch

Postby blinddrew » Tue Mar 10, 2020 10:52 pm

One of these days I'm going to have to read up on what PolyAT actually is.
Just so I can poke The Elf about it next time I see him of course...
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Re: A couple of questions about Poly aftertouch

Postby Martin Walker » Tue Mar 10, 2020 11:19 pm

blinddrew wrote:One of these days I'm going to have to read up on what PolyAT actually is.
Just so I can poke The Elf about it next time I see him of course...

In a word - Bladerunner!

Here's Vangelis to explain ;)

https://www.youtube.com/watch?v=zoEkyBX7qsg


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Re: A couple of questions about Poly aftertouch

Postby Hugh Robjohns » Tue Mar 10, 2020 11:37 pm

blinddrew wrote:One of these days I'm going to have to read up on what PolyAT actually is.

You play a chord, you press one (or more) note(s) harder, and stuff happens to that (or those) note(s) -- stuff like vibrato, filter brightening, volume increase... Or whatever you want to happen to make individual notes 'sing' as you play. It's incredibly expressive, and very addictive!
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Re: A couple of questions about Poly aftertouch

Postby blinddrew » Wed Mar 11, 2020 9:19 am

I thought it might be something like that. :)
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Re: A couple of questions about Poly aftertouch

Postby The Elf » Wed Mar 11, 2020 9:58 am

The best instruments are always capable of responding to both poly and channel AT all the time, with no need to change any settings. A good example is the Novation Peak.
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Re: A couple of questions about Poly aftertouch

Postby BJG145 » Wed Mar 11, 2020 10:16 am

The Elf wrote:A good example is the Novation Peak.

My initial thought had been that an instrument would only respond to one or the other at any given time, but I don't see why you shouldn't have both, with one effect responding uniformly to the current maximum keypress, and another responding individually on a note basis. Is that what the Peak can do...?
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Re: A couple of questions about Poly aftertouch

Postby Folderol » Wed Mar 11, 2020 11:58 am

So basically, this is a non-standard standard :roll:

The current situation for Yoshimi is that Chan AT is not directly implemented, but is made available for MIDI learning to any control of any part (or group of controls/parts).

In the development version on github, 'master' does Poly AT for filter cutoff (works nicely with brass sounds), and we are planning to enable a range of other options.
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Re: A couple of questions about Poly aftertouch

Postby The Elf » Wed Mar 11, 2020 12:00 pm

Folderol wrote:So basically, this is a non-standard standard
Roland XV-5080, Integra-7, JP-80, Novation Peak and Summit all work exactly the same way I've described. So does the ME80 CS-80 emulation. If there's any 'standard', I reckon this is about it.
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Re: A couple of questions about Poly aftertouch

Postby desmond » Wed Mar 11, 2020 1:17 pm

desmond wrote:
Folderol wrote:Is it normal (or even desirable) to have both channel and poly aftertouch available at the same time?

It's usually one or the other, as otherwise they will interfere, even if they are controlling different things (ie, pressing one key would always generate both channel and poly touch together).

If this wasn't clear, I was really referring to keyboard instruments *transmitting* channel or poly AT - they don't generally do both at the same time.

As far as *receiving* MIDI AT, then as usual on a synth, the user/patch should decide if either mod sources do something or not.
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Re: A couple of questions about Poly aftertouch

Postby Folderol » Wed Mar 11, 2020 6:45 pm

Still puzzling through this. What about multiple actions? For example would someone want to do something like a pitch bend and a vibrato effect at the same time?

P.S. Just added pitch bend to my local copy :)
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Re: A couple of questions about Poly aftertouch

Postby Hugh Robjohns » Wed Mar 11, 2020 6:47 pm

Yes, of course... But that's just sharing the Poly-AT modulation control signal to multiple effects destinations, surely, which is a perfectly normal requirement?
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Re: A couple of questions about Poly aftertouch

Postby Folderol » Wed Mar 11, 2020 7:28 pm

Questions might seem a bit simplistic, but please bear in mind I've never even touched an instrument with polyAT, and as I'm trying to design this in, I want to be as clear as possible.
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