You don't need a separate stereo mix unless it will have different content.
Your DVD or software player will do a much better job of downmixing to stereo than either you or I could, and I've been mixing audio for forty years.

The selection is automatic -- 5.1 goes to digital outs and stereo goes to analog outs. The mixdown flags are incorporated in your 5.1 audio stream. Nothing could be simpler.

Great answer, musicvid! Love the simplest solutions.

All good points, and thanks for your replies. I've been looking around at other forums, Q&As, etc., and still haven't quite found an acceptable solution....I don't know if there IS one, actually.

1. I understand what you mean about 5.1 automatically folding down into stereo 'OK' automatically, but I wanted more; just don't quite trust the process; I DO hear differences between the two, but I understand I may be stuck with choosing one or the other, and will have to mix accordingly. (See #4 below...)

2. DVD Arch "new project" menu's (all versions from at least 5.0 onward) have a selection box to click for audio; it is either "5.1 Surround" or "Stereo". So I assume once either is selected, the DVD (SD or BD) then "announces" itself to the player du jour and says: "I am a 51. Surround Audio Disc" or "I am a Stereo Disc". Period. If you ARE using a stereo-only output player, then regardless of type, it's going to be downmixed to stereo via the two analog jacks, no matter what.

3. DVD Arch (and all other software apps as well, I assume) DOES allow you to have multiple audio tracks (ie: English, Spanish, French, etc.) but again, I think once you've selected the 5.1 or stereo option, it doesn't matter what track you select; it sticks to the selected output format, regarless of the audio tracks, per se...

4. I've finally got my copy of DVD Arch 6.0 to properly play my 5.1 audio/dvd projects in preview mode, and voila; its downmixing to stereo - just another quick & easy way for me to preview it as a "stereo" downmix, I guess? Dumb luck if not, very nice if that was their plan all along....

5. I DID try the menu button process to create separate selections of audio tracks, but again, it always seems to play the surround audio track no matter which audio option was chosen. There's a help explanation in the DVD ARch software on how to use 'empty button' icons to select alternate audio tracks, but it's so difficult to read/comprehend, I couldn't follow it, and used my own process anyway - with probably the same results.

6. It also seems to me that if I WAS able to get it to play the stereo track (instead of the surround version), all I'd get would be an Up-mix to 5.1 anyway, on players that were already setup for 5.1

..... IS ANY of this making sense? ;-)

Also, the client (who started all of this head-scratching with me) seems to agree we use the following quidelines going forward: Stereo Mixes for the Audio CDs, and 5.1 Mixes for the SD & BR DVDs.

Until/unless I find another solution, I think that's the only way forward.

I don't have a clue to what you were saying about DVDArchPro6 downmix preview...works the same as others. BUT you should know there are some audio bugs intro'd in 6.0 version that wasn't there before.

As far as your surmises you are on the correct wave. What is easiest to manage is offering many alternate audio tracks in stereo or that is two channel mono if you want. Offering a direct 5.1 track of input is nice idea, but your alternate track options become convoluted and really offering the producers stereo mix-down into the authoring process is just the best way to go.

No, none of this is making any sense.
1. Eagerly awaiting your 5.1 and custom-mixed stereo examples for comparison. Dolby gets it right.
2. 5.1 and stereo audio tracks can reside quite happily on the same 5.1 disc, as many tracks as you like (up to eight iirc).
3. When in doubt, refer to #2. DVDA does not "change" stereo to 5.1.
4. DVDA preview is stereo. It doesn't preview encoded 5.1.
5. Audio selection buttons and submenus are a snap to set up. Follow your brain, not the directions ;?)
6. No. Digital output is surround or stereo, analog output is native stereo or mixdown.

Re #5 - I reread the OP's comment which MV10 responded to and would like to try to interpret what I understand the OP is stating. I think that I had misunderstood upon my first read.
When you want to set-up alternate audio track selection on a DVD disc -you do have to carefully conform to some best practices.
a) Establish what number of an audio track is the default track that is default for the entire disc . b) provide tracks in the same positioning across all video assets. If you create three video assets, you will need two alternate tracks for each one video - even though one of the three videos does not have an alternate audio track - it must have an 'empty' alternate track position. c) provide a means to select track - as in a setup menu, or simply by specific menu link call-out. d) give the casual viewer , some instruction or cues on where the alternate tracks exist or do not exist so they can make intelligent decisions. d) recognize that depending on the set-top player track selection might be by the set-top player's remote control directly or sometimes thru a navigable on-screen interface with the remote.

With that being established - recognize that set-top player firmware may handle the default track authoring of your disc in a different manner such that a default established track and track one play are not necessarily always the same.