Help with multiple knock Sensors across 4 Analog pins...

Projects Programming
20 
  AnalogVal = analogRead(knockSensor);
  AnalogVal2 = analogRead(knockSensor);
  AnalogVal3 = analogRead(knockSensor);
  AnalogVal4 = analogRead(knockSensor);

This reads the same analogue input 4 times into 4 different variables. Did you mean to do this and if so, why ? Weren't you using an array of sensor pins in previous versions of the program ?

each time I try and add some kind of threshold for each analogRead, it's all errors...

Please post what you tried and the errors that it produced