Need explanation for shunt-type volume control

[Navyblue]

Please refer to the hand-drawn diagram in the middle of the page:

Shunt Pot Volume Control - World-Designs-Forum

Why 1 and 2 need to be shorted? Why can't we just connect 2 to ground and leave 1 unconnected? What does it do apart from altering the resistance curve?

Thanks.

 

[Navyblue]

Come on people, I'm sure it isn't that hard.

 

[no_eye_dear]

Hi NavyBlue, it's common practice to do it this way because the wiper may loose contact with the resistance material temporarily (dirty or oxidised).
All depending on the components before and after, this can give you pops and crackles as well as short blasts of full volume.
It's not always required, just good practice.

 

[Navyblue]

I see, thanks.