Thanks to KostasT, for answering my last round of questions.
Well, I took the plunge and purchased an MX61, but after many, many hours of trying to set it up to work with Studio One, I was ready to SCREAM !
I hope one of you can help me or point me in the right direction.

First Setup Try:
I have an Audiobox interface that connects to my computer via USB.
I connected my speakers to the Audiobox, then the MX61 to the computer via
USB only.  The Audiobox is setup in Studio One as an external source.  I then ran
the Yamaha Driver’s for the MX61.  Set that up as another external source.  Then I
set the MX61 up in S1 as an instrument/keyboard.  I tried everything to get the sound
to come out of the speakers connected to the Audiobox, when I played the MX61.
Nothing !, So I concluded that you cannot monitor the MX61 through another midi interface,
at least with S1.  Not sure it is true, but I would love to hear your thoughts.
Second Try Setup:
I moved the speakers to be connected to the MX61.  Awesome, I had sound.  So, my next test
was to see if I could play the MX sounds, and then the S1 sounds independently on different
tracks, and record them, (which I was very excited about for the MX sounds).  I firmly believe
I got this to work once, then everything went haywire.  I finally ended up in a state where I could
play any sound from the MX, independently, hear it over the speakers, and record it.  Then, I could
also play any sound from the MX, and somehow combine it (layer it) with any sound from S1, I could
hear them and record them.  BUT,—I could never get back to just playing the S1 sound without
hearing the voice from the MX61.  Am I missing something really simple??

I only have installed the latest Yamaha MX driver for 64 bit.  There are about 5-7 other updates
on the Yamaha site.  So, my guess is that they don’t bundle all software/firmware/etc updates
into the most recently dated one ?  Which seems crazy !  So should I install all of them, and will they
help the issue I described above ??

I also plan to talk with Studio One, but it was a long night..

Thank you in advance for any & all help.
SupperClub

Although I don’t exactly understand your setup, I guess that you want to hear the sound of a software instrument (or VST instrument) played by the MX61 keyboard, without hearing any sound from MX61. In this case you have the turn local control to off. This can be done either by:
[UTILITY]  Select “02:MIDI”  [ENTER] “LocalCtrl” = “off.”

or what I prefer doing:

Press [UTILITY]  [JOB]  Select “01:QuickSetup”  [ENTER]  Set “Type” to “DAW Rec”  [ENTER].

For more info read the reference manual from page 31 about the various settings.

Hope it helps.

Thank you so much, I will try this tonight.

I really appreciate you trying to help…

I’ll keep ya posted

Supper Club

That worked !!!

Thanks again..

SupperClub