Pop refers to a fizzy beverage, not a fizzy sound.

"Dear Sir,

I respect you and your linguistic prowess considerably. (Do you hear a "but" coming?)

However, I regret to inform you that POP refers to a drink. A sugar-filled drink with much effervescence. Also referred to as soda, cola, coke, soda pop, and most recently P O P.

As much as I would like it if Paul Simon would visit, it is recommended that he come bearing the sweet stuff, if he would like to enter."

...so spake, The Movie Night Management Mistress