Brennon Bortz

I'm trying to sort out a way to crossfade between four signals using a 

. The application seems obvious, and someone is bound to have done this before, but figuring out how to implement is eluding me!

I'm trying to sort out a way to crossfade between four signals using a [pictslider].  The application seems obvious, and someone is bound to have done this before, but figuring out how to implement is eluding me!


four-signal-crossfade-with-pictslider

 is all the way to any of the four corners, only one signal should be at full amplitude.

To clarify, if the control point of the [pictslider] is all the way to any of the four corners, only one signal should be at full amplitude.


when you have 4 signals A, B, C, and D, you would simply mix A vs B AND C vs D controlled by vertical movement, and then in a second step you would mix AB vs CD controlled by horizontal movement.

of course, depending on the application, you might want some weighting (such as "equal power" when it is for a 2 speaker setup)

A B   C D
[+~]  [ +~]
AB   CD
[+~]
ABCD

of course, depending on the application, you might want some weighting (such as "equal power" when it is for a 2 speaker setup)


the way I'd do it is get the coordinates and calculate the distance between the slider position and each of the 4 corners (using pythagorean method) and then independently attenuate the 4 sources according to how far the slider is from each of the corners (some sort of inverse relation. Then add them together.

Terry, that's the same thing I thought...but it doesn't fit the needs of my clarification, due to the square's geometry:

Roman, that did the trick--thanks! For reference:

Roman, that did the trick--thanks!  For reference:


yeah I see what you mean, only the diagonally opposite source is completely attenuated. You could change the scaling and have a floor of zero like this:

Roman's way looks neater, but I'd also get the sqrt of the four gain values for equal power crossfading

here is an excerpt from the nodes helpfile.

why not simply using the [nodes] object.
here is an excerpt from the nodes helpfile.

What a sweet object--how have I not seen this before?!

Yep, nodes is pretty nice object, however it still doesn't deliver 1 as a sum of the mixing, apart from corner positions.. Or am I missing something?

Untitled13.maxpat

I'm still trying to achieve 4 audio signals mixing with [pictslider] with the goal to have a constant amplitude = 1. when the 4 guys are mixed. Now it seems pretty close, but there is still some slight deviation at certain positions. Any ideas?

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Four-signal crossfade with [pictslider]