Quad Experiment

[Eddyp]

I've had a bit of a strange idea about building a Joystick controlled quad panner, it's not ment be a surround sound type format but rather an effect.
I'm baseing the circuit on a mixer channel but have run up against a few problems. Firstly finding a suitable joystick was a bit difficult (any suggestions?). What I was thinking of using was a penny and giles unit (£££) this gives 2 linear voltage outputs, X,Y.
I used these O/P's to create 4 voltage sources that could control some sort of VCA's to create the pan effect for the 4 loudspeakers, FL, FR, BL, BR. The problem is that my voltages vary linearly to the joystick but i need a log response from the VCA's, any ideas?
Any other comments about the idea would also be greatly appreciated..
Cheers......

[planet10]

Originally posted by Eddyp
Firstly finding a suitable joystick was a bit difficult (any suggestions?)

I have a joystick salvaged from an old fisher 4 channel amp -- it is 4 pots and some metal guides. It's yours for the cost of postage.

dave

[bigparsnip]

you could try loading up the linear pots with a low value load resistor which then will distort teh linear effect of the pot and give you something that vaugely resemebles a log pot. Rod has an article based on this ide on his site (here) if you want a bit more explanation, but I'm not entirely sure it will work, if you want two seperate log halfs in each axis on you joystick.

andrew.

[Eddyp]

Cheers for the advice guy's, I had a bit of a think last night and came up with the idea of using a PS2 controller joystick, i'm gonna try and combine this with the circuit suggested and see what happens. (probable a nasty burning smell)
Thanks for the offer anyways Dave..
I'm still intrested to hear any other suggestions about the idea, i'm thinking of putting some sort of variable delay on the rear speakers??? what ya reckon?