Re: How to write a sequencer?

No, my UI has nothing to do with it, this could be run without any UI at
all. There is no static sequencer with a static sound-source to control, in
my system the notesequencer is an independent module like any other module
that produces a signal. The module doesn't know (or need to know) what is
being done with the signal. It could could be connected directly to an
oscillator, or filter (or ten of them) to control their frequency, it could
be run through other modules first (a slew limiter, a noteshifter, strange
waveshapers), or it could not control any frequencies at all and be run
very fast to run as a strange oscillator. That's all up to the user.

Peter

2012/8/6 Chris Rogers <crogers@google.com>

>
>
> On Mon, Aug 6, 2012 at 12:28 PM, Peter van der Noord <
> peterdunord@gmail.com> wrote:
>
>> I'm not sure your example is what i am looking; i need something that
>> outputs that sequence as a signal (in patchwork, i use 0.2 "Volt" per
>> octave, so the lowest frequency would be a signal of -1, and the highest,
>> 10 octaves higher, at 1), so i can control other things with it (my
>> notesequencer doens't directly control other modules itself, other modules
>> are controlled because they interpret that signal).
>>
>> But i guess that should be done in the same manner as a triggersequencer
>> (have a module that outputs a continous signal of 1, connect it to a
>> gain-control, and set the gain-control accordingly)
>>
>> Hmm...
>>
>
> Peter, the way I would think about it is how to achieve the desired
> behavior for the application (what the user hears, sees, and interacts with
> on the page).  In other words, I think you should be able to present a
> "signal" representation of events in your UI without actually using an
> actual audio signal in the underlying JS code.  Instead, you can use the
> scheduling primitives available in the API (such as note event and
> fine-grained AudioParam control) as the actual implementation.  What the
> user sees on the screen can be whatever you want.  It feels like you're
> trying to create an exact 1:1 mapping between your UI and the underlying
> API calls.  From the user's perspective they won't care how you achieve
> your result as long as it works.
>
> In other words, there needs to be an appropriate level of MVC (Model View
> Controller) abstraction:
> http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller
>
> Chris
>
>
>
>>
>> Peter
>>
>>
>> 2012/8/6 Chris Rogers <crogers@google.com>
>>
>>>
>>>
>>> On Mon, Aug 6, 2012 at 8:51 AM, Peter van der Noord <
>>> peterdunord@gmail.com> wrote:
>>>
>>>> In the light of all the discussion about the limitations of the
>>>> jsnode(at least for writing audio) i was curious about any ideas how i
>>>> should write myself a sequencer using the native nodes.
>>>>
>>>> I need both a notesequencer (sends out frequencies mapped to the -1,1
>>>> scale) and a triggersequencer (that can send out a single value of 1). I
>>>> thought about having a jsnode scheduling a gainnode which has a
>>>> buffersourceconnected to it that's playing a looped buffer containing just
>>>> one value (a 1).
>>>>
>>>
>>> Hi Peter, I've actually done something like this although it's very much
>>> unfinished and was written before we had an Oscillator  node.  Please don't
>>> use it as a definitive guide, and I know there are bugs there, but still it
>>> might give you some information:
>>>
>>> http://chromium.googlecode.com/svn/trunk/samples/audio/wavetable-synth.html
>>>
>>> I have a simple UI for it, but others could be written letting you draw
>>> custom curves, etc.
>>>
>>> For a monophonic subtractive synth you can create a single Oscillator
>>> node, turn it on (with noteOn()) and just let it run forever, add an
>>> AudioGainNode for the amplitude envelope, add a BiquadFilterNode (or two or
>>> three...) for the filter.  You can control the monophonic note events by
>>> "gating" the amplitude and filter parameters appropriately (something like
>>> my example above).
>>>
>>> Hope that helps,
>>> Chris
>>>
>>>
>>>
>>>
>>>> - are there better ways to do this?
>>>> - i read about the dezippering of the gainnode. It's unspecified, but i
>>>> assume it filters out fast changes. Woulnd't it be a good idea to be able
>>>> to turn that off? If you want to do AM with it, you're not really looking
>>>> for a node that interferes with your controlsignal.
>>>>
>>>> Peter
>>>>
>>>
>>>
>>>
>>
>