Okay, Guys, I thank you very much for your comments. Here's an update:
As to the Model of my own DVD player, I mentioned it in my previous post, an APEX AD-1200, which is just an ordinary non-writable player that I got on-sale in Walgreens.
As to the 'audio' button on my Remote, it is there and my instruction manual says that it can be used during playback to select 1 of 3 'channels', which can be 'cycled' forward or backwards by depressing the 'audio' button' Here's from the Manual:
"Recording Systems:
This DVD player uses the Dolby Digital, MPEG 2, PCM and DTS recording systems. It cannot playback DVD disks recorded in any other format."
But then the next two statements become confusing!
"The player returns to the initial default settings, when you turn on the DVD video player or replace a disk.
The DVD video player plays the prior sound programmed on the disk, when you select a format which is not included on the disk."
"... prior sound programmed on the disk..."???
Okay, I will admit that the 'audio' button is located right next to the other buttons that I was attempting to press in the dark.
As to the actual audio 'Set-Up', the Manual says to go to 'Set-Up' on the screen, then down to 'Audio Output', and select "SPDIF/RAW" from the three selections, the other two selections being "SPDIF OFF" and "SPDIF PCM". However, I have 'cycled' through all three of these selections while the disk is on playback and it made no difference, (i.e., the Music-instead-of-Voice track continued!)
Now, however, getting back to the 'audio' button on the Remote, when I try to do as the Manual says, i.e., cycle through the supposed three-track 'selection'... NOTHING HAPPENS! The 'audio' button is DEAD! No response at all!
Now, let me ask one further question here. I've used electronic controls where a 'combination' of buttons were required, such as 'Ctrl' + 'C' on your keyboard. I am wondering whether, when I was pushing all the wrong buttons in the dark, whether I might have hit the 'audio' button, switching audio tracks, and then hit another button, say the right next door button(s), 'slow', 'step', or 'setup', which then completed the 'combination' required to 'turn-off' the 'audio' button, or... Fantasy of Fantasies! Enable a 'Bill Gates-like Underground Manufacturer/Factory-Only Menu, Not for Public-Use", that I didn't notice, but which 'accessed' factory-only features on the disk!
Anyway, the 'audio' button is dead!
One more thing! On my Rental DVD disk (the other disk!), where there is noise instead of normal audio, but the audio can almost be heard when I turn it up to maximum... Guess what? That disk has 12 'scenes', and Lo and Behold, when I finally clicked on the 12th and final 'scene', that last 'scene' HAS FULL AND PERFECT AUDIO! But all the other 11 'scenes' are dead!
I guess that means the rental DVD is 'defective'! But I'd still like to switch my own disk from 'muzak' track to audio track, and I guess the key to that is to somehow get the 'audio' button to work!
Any ideas, Guys?