How to do a variable audio low-pass filter?

Other Hardware General Electronics
1

I am designing a synth and want to add a low pass filter, I have advanced a lot in the programming but I really don't know that much about electronics.

I found this webpage about filters: http://www.electronics-tutorials.ws/filter/filter_2.html

Would that very simple lowpass filter work if I add it to the audio signal? And how can I variate the resistance value so the cutoff frequency can be changed?
A simple potentiometer with the right resistance will work, right? If I want to change the value inside Arduino programming I thought it can be done with a digital potentiometer, right? Any other way??

Thanks!

2

Using dig. pot is the easiest way, only to make it's more "focused" you should add some OPA. Here is a link:

3

Woa! that doesnt seems that easy.

I will try with a simple pot first and then I'll try that way.

Thanks!