Pressing the red test switch on the S&T board should produce all of the speech, including I believe some phrases that aren't (or at least seldom) used in play, and a few effects. Vector's too early for music as such, but there'll be a background sound.
When using the test button on the door, the tests which come first aren't as extensive or flexible as with more modern games. The audio test is fixed as one sound*, and only really shows whether there is an audio output, and how loud, using the volume control on the door. As Carl says, after the Bookkeeping stuff, and the clear adjustments for replay scores, current value of Highest score, etc, numbers 16 onwards are what's called 'soft' adjustments, held in Ram. Things like Highest Score award, Replay/Add-a-Ball mode, etc, including audio palette. Generally, 03 is best for No.s 16 through 19. No.s 20 & 21 are for an option to hold/adjust sound and speech volume in Ram, which was rarely if ever used.
* as I recollect anyway, from my contemporary Centaur