Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO)

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To: Nick Copeland <nickycopeland@...>
Cc: linux-audio-dev@lists.linuxaudio.org <linux-audio-dev@...>
Date: Wednesday, August 22, 2012 - 1:57 am

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On Wed, 2012-08-22 at 03:24 +0200, Nick Copeland wrote:
[...]

Yes. "Controls" and "ports" are interchangeable.

> There are other examples but when I was starting on Bristol this

The context and goal here is modular synthesizers.

You may not like modular synthesizers. Fair enough. Some do.

> The other parameter that is going to be an issue is transpose. You

I am not sure why you think ports are a "waste of CPU", but that is not
the case at all.

> Also, the original synths did not have a

"Properties", "controls", "ports", whatever. I am not sure what kind of
semantic mapping for these terms you are imagining, but we have input
and outputs ("ports"), and that's it (and that's a good thing).

> It can be argued here that you are not intending to actually emulate

Because these plugins use 1/Oct and I want to use them. These filters
are an emulation of the Moog filters.

I am not talking about the internals of a static program here. These
plugins are generic and can be used in any program, which is why the
interface matters.

> Also, if you do want to use V/Oct then perhaps also get rid of -ve

Frankly I don't see how this idea makes any sense at all in a digital
system. If you want to modulate frequencies - which you certainly do -
then you'll need negative values. This position is a blatant
contradiction of basically everything else you've said Re: absolute
units. In your previous email you went on about how the absolute unit
is bad because you can't use it for an amp... well, amp gains usually
center about zero (0db being unity gain), and negative values are
neither uncommon nor problematic. In floating point systems like this
one, audio itself centers about zero. Things *not* also being centred
about zero is annoying for this reason.

Perhaps you are thinking about integer audio? Like Jack, we do not use
integer audio.

In short, for relative signals this is nonsense. For absolute
frequency, it is a possibility. It raises some questions:

1) If absolute is bad, then... why use a range that is inherently
absolute? "No negatives" =3D> "not usable for relative modulation"

2) What frequency is 0? Note that this number, doubled repeatedly, is
going to have to hit 440 (or at least some note) at some point for this
unit to be at all sensible. That means it isn't going to be a nice
round one. Why spec a unit based on some very strange ugly low
frequency rather than standard 440?

3) What is the advantage of using a unit completely *unlike* audio, when
the entire point of CV is to be interchangeable with audio? For
example, if you connect a normal audio sine wave to a zero centred
frequency port, it will give you a frequency sweep of 2 octaves.
Multiply that audio and you get a wider range, and so on. Presumably
this is why AMS and by extension Fons' plugins chose this unit in the
first place. A positive-only unit is very non-modular and less useful.=20

3) What exactly has been gained to compensate for the loss of ability to
represent any frequency below whatever you choose for 0, and the nice
CV-like behaviour described in point 2?

Blind emulation of voltage is not the goal here. The audio in these
digital systems is different. The point of modular synth-like systems
is interchangeability between CV and audio. Since the audio is centered
about zero, the correct way to capture the spirit of modular synths is
to also center CV about zero. Presumably this is why AMS went with it
in the first place.

-dr

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Messages in current thread:
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), Jeff McClintock, (Mon Aug 20, 11:02 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), David Robillard, (Tue Aug 21, 12:50 am)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), Nick Copeland, (Tue Aug 21, 8:14 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), Fons Adriaensen, (Tue Aug 21, 9:54 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), David Robillard, (Tue Aug 21, 10:29 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), Fons Adriaensen, (Tue Aug 21, 11:02 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), David Robillard, (Tue Aug 21, 11:50 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), Thorsten Wilms, (Wed Aug 22, 8:30 am)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), David Robillard, (Wed Aug 22, 4:43 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), Fons Adriaensen, (Wed Aug 22, 9:12 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), David Robillard, (Wed Aug 22, 9:32 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), Fons Adriaensen, (Thu Aug 23, 10:56 am)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), David Robillard, (Thu Aug 23, 4:06 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), Fons Adriaensen, (Thu Aug 23, 4:35 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), David Robillard, (Thu Aug 23, 5:07 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), David Robillard, (Wed Aug 22, 5:37 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), Nick Copeland, (Wed Aug 22, 1:24 am)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), David Robillard, (Wed Aug 22, 1:57 am)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), David Robillard, (Tue Aug 21, 8:59 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), Nick Copeland, (Tue Aug 21, 10:11 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), Jens M Andreasen, (Wed Aug 22, 3:50 pm)
Re: [LAD] Plugin 1/oct frequency controls (AMS/MCP/VCO), David Robillard, (Tue Aug 21, 10:52 pm)