Luke's line here is a different take.

"So, you got your reward and you're just leaving then?"

Mono Sound Mix:

Dolby Stereo Mix:

Porkins' scream is not heard in the mono sound mix.

Mono Sound Mix:

Dolby Stereo Mix:

The voice on the Death Star--"The rebel base will be in firing range in seven minutes." etc.--is different.

Mono Sound Mix:

Dolby Stereo Mix:

"The rebel base will be in firing range in seven minutes."

"Rebel base three minutes and closing."

"Rebel base one minute and closing."

"Rebel base thirty seconds and closing."

"Rebel base in range."
"Commence primary ignition."

Luke says "Blast it, Wedge! Where are you?" instead of "Blast it, Biggs! Where are you?"

Mono Sound Mix:

Dolby Stereo Mix:

Many transmissions during the battle of Yavin are not synthesized. 

RED LEADER: (over speaker) Rendezvous at mark six point one.

WEDGE: (over speaker) This is Red Two. Flying toward you.

BIGGS: (over speaker) Red Three, standing by.

Mono Sound Mix:

Dolby Stereo Mix: