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Re: Thoughts and questions on the API from a modular synth point of view

From: Peter van der Noord <peterdunord@gmail.com>
Date: Wed, 18 Jul 2012 14:12:53 +0200
Message-ID: <CAL9tNz_=VANrN4RgMm2iAdJYtZWvvuw2JaD8sYR7E9EjVm7YkA@mail.gmail.com>
To: Marcus Geelnard <mage@opera.com>
Cc: public-audio@w3.org
> Can you detail for me why you'd be more interested in driving such gates
from an a-rate or k-rate style > parameter?  I can understand what you're
asking for and how it would work, I'm just trying to think of > > when I'd
want to do it that way.

I've made an example of how i'd want to use that a patch in my flash synth
(hold spacenar to drag the patch around)

http://patchwork-synth.com/?p=713b5f59c88e440a96dd99798f5671f2

There's one clock driving this whole patch (my clockmodule sends out a
signal of zeros with a single sample of 1 for a pulse, although
trigger-inputs react to signals that change from <=0 to >0)

- the main clock trigger a sample
- the clocksignal goes to a clockmultiplier, craeting a variety of synced
pulses
- one of the mutiplied outputs is used to proceed a trigger sequencer
- one of them is used to proceed a note-sequencer
- one of them triggers an envelope (used as amplifier on an osc)

The key idea is that i can use one type of signal (a trigger/gate_on in
this case) and use it to drive a variety of events, where every module
interprets this trigger in its own custom way. When events in nodes in the
current Web Audio API can only be triggered (or scheduled) by methods, it
doesn't allow for the things i made in the example.

And it's not just clock-related modules that can send out gates in a useful
way, in the following example i use a note-quantizer (which rounds an
 incoming signal to note-frequencies (according to a mapping i chose: 0.2
'Volt' per octave) that sends out not only the rounded signal (which sets
the freq on the osc you hear), but also a trigger signal whenever the
rounded signal changes. That trigger is used on an volume-envelope to start
the note:

http://patchwork-synth.com/?p=32824e67109d44088aa187f19a63e68f

Hope this explains something about interesting uses of gate/trigger signals.

Peter


>
>
> 2012/7/18 Marcus Geelnard <mage@opera.com>
>
>> Hi Peter!
>>
>> Some of your questions are being dealt with in the bug tracker. Chime in
>> if you have more input.
>>
>>
>> Den 2012-07-15 05:50:08 skrev Peter van der Noord <peterdunord@gmail.com
>> >:
>>
>>
>>  - is there a way to retrieve more info about an audioparam? (name,
>>> description)
>>>
>>
>> AudioParam.name was removed: https://www.w3.org/Bugs/**
>> Public/show_bug.cgi?id=17397<https://www.w3.org/Bugs/Public/show_bug.cgi?id=17397>
>>
>>
>>
>>  - It looks like the JavaScriptAudioNode has an unchangable number of
>>> inputs and output. This freaks me out :) Is it going to stay this way?
>>>
>>
>> https://www.w3.org/Bugs/**Public/show_bug.cgi?id=17533<https://www.w3.org/Bugs/Public/show_bug.cgi?id=17533>
>>
>>
>>
>>  - Can't i add Audioparams on a javascript audio node?
>>>
>>
>> https://www.w3.org/Bugs/**Public/show_bug.cgi?id=17388<https://www.w3.org/Bugs/Public/show_bug.cgi?id=17388>
>>
>>
>>
>> /Marcus
>>
>>
>>
>> --
>> Marcus Geelnard
>> Core Graphics Developer
>> Opera Software ASA
>>
>
>
Received on Wednesday, 18 July 2012 12:13:21 GMT

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