[LAD] panning thoughts

fons at kokkinizita.net fons at kokkinizita.net
Mon Nov 22 14:36:30 UTC 2010

On Mon, Nov 22, 2010 at 02:14:54PM +0100, Remon Sijrier wrote:

> On Sunday, November 14, 2010 01:01:17 am fons at kokkinizita.net wrote:

> > Let me guess: a combination of a badly designed widget that has no
> > central position, and a print format that doesn't show the smallest
> > step.
> Hmm, you never used Traverso I see ... at least not in the way it should be 
> used: there are no widgets in Traverso to control gain/pan values. 

I have a look at it every now and then to see how it's evolving. Last time
it still was limited to stereo, and it crashed within minutes. Which does 
indeed mean I don't use it.
> But you are correct that the pan/gain 'indicators' have less precision then 
> the actual gain/pan values.
> One of the reasons I didn't fix this earlier is due I've no idea how much 
> precision is needed. I.e. how small a step value do we want/need for gain and 
> pan, and do we actually want to show that in the indicator? E.g. a value of 
> -3.05 dB is a bit overkill?

There's a simple rule: if the indicator says '-3.0' then the actual value
should be -3.0. Not -2.96 or -3.04. In other words the indicator should have
the required precision to be able to show *all* possible values exactly.
Steps of 0.1 dB for gain are perfectly OK, even bigger ones. You have
to 'smooth' the transition anyway if the gain changes.

> Right now gain increment steps are 0.05 dB for gain, and there are 200 steps 
> for pan normalized between -1, 1

I hope '200 steps' means 201 positions. You need an odd number in order to
have a central position.
> Just some thoughts: rotary knob controls are better to control by the human 
> then sliders are, probably due the movements of the fingers are much more 
> precise?

Real ones provide support so the user can hold the knob without moving it even
in shaky conditions. 

> The use of sliders vs knobs in software imho still is a different issue since 
> you have to control those with a mouse, right?
> And this mouse movement dictates how good the movement (and precision of that 
> movement) can be done in combination with how the knob/slider 'widget' is 
> implemented. E.g. the width of the slider is 100 pixels, then you can't use 
> more then 100 steps.

You can, and in fact the sliders I'm using in some new projects do have
sub-pixel accuracy, also visually.

> Traverso does away with that by using the relative mouse moving distance, 
> allowing for mouse movements to be translated in relatively small gain/pan 
> adjustements in effect giving the user a much better control over the 
> gain/pan/other values. 

Relative motion is the only one that makes sense for a slider. There's nothing
more useless than a control that jumps to the value you click on.

> Side effect is that the mouse can be moved physically 
> for over long distances without being limited by screen sizes, so no matter if 
> you're using a large or small screen, a large or small knob/slider, it always 
> feels the same, with much more precision :)

Which in general is a good idea. OTOH, fader attenuation should 'go faster' for
low gain values (e.g. below -40 dB w.r.t. the maximum), so a fixed step is not
always optimal.



There are three of them, and Alleline.

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