Mapping troubles

Jay Simpson's icon

Evening,

I have been trying to map a slider to act as a scrathcer for sfplay~. From the middle to the right side of the slider needs to be mapped to give a value range of 1 to 2, and from middle to left needs to cover the range -1 to -2. How can it be done? Any ideas?

Thanks

J

Here is my attempt so far

Max Patch
Copy patch and select New From Clipboard in Max.

Jean-Francois Charles's icon
Jay Simpson's icon

THANK YOU!!!! Yes that is exactly what I mean, my maths skills must be appalling not to be able to work that out. Cheers!

Jay