[LAD] panning thoughts

Remon Sijrier remon at traverso-daw.org
Mon Nov 22 19:06:20 UTC 2010

> > 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.

Understandable... we're open for suggestions and bug reports about those 
issues of course!

> > 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.

OK, makes sense. I'll stick with gain in/decrement steps then of 0.1  dB.
T at the moment doesn't smooth transitions of gain/pan values when the user 
changes those when transport rolls.
is this much of an issue ? 
Keep in mind that gain automation uses an interpolation for the gain value 
calculated and applied per sample.

> > 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.

yes, 201 positions, 100 steps in both directions and the central (zero) 
If this kind of precision isn't needed, then I can change that to use the same 
resolution as midi (128 steps) or perhaps a multiple of 128?

> > 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.

How do you move sliders with a mouse with sub-pixel accuracy ?
(maybe I'm misunderstanding the sub-pixel accuracy way of moving a graphical 

Thing is that the 'pan/gain slider' in Traverso isn't used for changing that 
value, instead you just 'activate' the 'change pan' key and then move the 
mouse. The distance of the mouse movement is calculated with respect the 'old 
mouse position' and from that value the pan/gain change is calculated and 

For pan you keep the P key pressed and move the mouse, the whole track is 
sensitive for that key. Similar for Gain, then you have to use the G key.
To please some stubborn users that insist on trying to click with the mouse on 
that damn tiny pan/gain slider, it was added as a 'key action for pan/gain' 
too, but it's considered bad practise :)

This 'virtual' slider equals a size of 600 pixels in Traverso, but is easily 
changed into any value you want. So to pan hard left you have to move the 
mouse 300 pixels to the left, and vice versa.

Ciao, Remon

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