> no one can hear you explode.
Of course they can...if someone is sufficiently close and the shockwave hits a reverberating surface containing an atmosphere that can transmit the resulting sound waves to your auditory sensor. The TIE Fighter sounds were ion streams (from their engines) hitting the hull. That's how close they got to the Falcon!
I believe a simpler and more sensible explanation for the roar of the TIE fighters flying through space is that nobody on screen heard them. They were simply added for effect, for the benefit of the viewers in the audience. Those scenes would have lost luster if those sound effects had not been added, same with the sounds of the laser blasts and explosions.
Likewise, it is highly unlikely that any of the characters on screen would have heard the Main Title, the Imperial March, or any other number from the soundtracks (other than the likes of the Cantina songs, Max Rebo's music, the Ewok Celebration, or the too painful to remember Life Day song that Princess Leia sang).