pan switch help?

[dougdeeper]

hello!
im building a virtual ground line mixer (unbalanced) and would like to use a lcr pan switch instead of a pot.
could anyone direct me to some theory on such a thing?
if the l and r are feeding 10k resistors, what value should c feed?
for the center position there should be extra resistance in series with l and r am i right?
and for l and r the unused side when panned hard should be grounded?
thanks for any help!

 

[JohnRoberts]

If this is unbalanced it's pretty simple

L only is Rin= Rf to L bus only.
R only is Rin= Rf to R bus only.
C is  two  Rins each = 1.4x Rf (for - 3dB pan law) , one to each bus.

JR

 

[dougdeeper]

so no grounding of the unused side is necessary? (ie grounding the right when panned left)
thanks! 

 

[JohnRoberts]

You said unbalanced, so there's no spare parts.

Pan switch either connects the resistor or doesn't.

JR

 

[PRR]

> so no grounding of the unused side is necessary?

You said "virtual ground line mixer".

The biggie virtue of VG-mix is that unwanted inputs may usually be left open.

In passive mix, disconnecting inputs causes less loss, so the other inputs get louder. This is perhaps the main annoyance which led to VG mix.

Mebbe I spent too much time on stages with orchestras and big-bands, and working in simple stereo imaging, but I can't see mixing more than three performers with only L-C-R pan. We usta spread and space musicians across the stage for blend, clarity, and separation. L-C-R gives three slots, each jammed with players, and big empty gaps between? Yeah, on the average playback system, nobody will notice, any "image" is an accident of artificalness.