Ok so I replaced all of the resistors with 1Kohm resistors but now I am getting very low readings from the piezos. For example, my threshold was originally set to 300, now I have to use a threshold value of 2 and since my values are so low, sometimes I miss a knock.
I have a total of 9 analog pins reading the piezo sensors. At the moment I have only 1 piezo connected (all resistors are connected and grounded), and I am often getting a reading of 1 from the other pins. How can I set this up to make my readings as accurate as possible?