unzip the nvram file into the nvram directory so you can
play Panthera with specials on, extra ball on, 2 credits
for high score on, high score on, and 3 ball on.

Hit f1 when the game is playing and change the
default sound freq number to 5000. <very low>..otherwise
the real sound will irritate you to death. 

OR 

you can turn off the emulated sound and just play
with the wavs on.

