Playing radio sounds

[Playing radio sounds]

Ok when i use my numpad to switch radio freqs i get game sounds associated with each key ie if i hit #1 on the keypad i get a horn sound if i hit #2 i get an explosion ect 

any ideas why is there a setting to disable it ?

[keypad plays sounds]

Ok when i use my keypad to switch radio nets on the 152 or the LR when i hit a number key on my keypad it plays a game sound how do i stop this ???? just started happening