I understand that when the XS Rack is set to USB mode, the MIDI in/Out ports are disabled.

Not true. The MIDI IN/OUT ports become available for an external device to connect to the computer. They are NOT disabled, not at all. The Motif-Rack XS uses port #1, and the 5-pin MIDI jacks become Motif-Rack XS port #3.

When you select MIDI IN/OUT = USB the Rack XS becomes a MIDI interface for a single external device connected to its 5-pin MIDI jacks. The jack no longer address the Rack XS directly, they simple pass the data through to the computer where it is seen by the computer as "Yamaha Motif-Rack XS-3 (port 3)". And track routed out from the computer on "Yamaha Motif-Rack XS-3 (port 3) will arrive at the 5-pin MIDI Out jack of the Rack XS.

Sorry, I can't help you with any of those other devices

UPDATE:
My rig has changed somewhat, and I wanted to post an update, as well as ask for assistance with how to best implement two MIDI controllers with different MIDI channels into the Rack XS. The real head scratcher is with the Studio Manager software, since I can only get the Arturia KL88 (Channel 1) to sound if I have the MIDI Thru checked and the KL88 on the left and Port 1 on the right.

That being said, I also own an Arturia KeyLab 61 and have set it up on a 2nd tier as MIDI Channel 5. Considering the above, do I plug another USB cable from the KL61 to the Rack XS, or I do I use a standard 5-pin DIN MIDI cable going out to the KL88 MIDI in? If I go with USB, how does Studio Manager know to process input from both KeyLabs since only one can be specified as the MIDI Thru source?

The other big change is that I'm no longer using Windows 10, but have switched to a MacBook Pro. This radical change was made to accommodate the MusicIO app so I can run a USB cable directly from my iPad to the laptop, thus eliminating the need for all hardware based MIDI-USB devices.

Thanks Again!

Studio Manager software? Yikes, that version of the Editor is from seven years ago.
Perhaps you should start by updating your Motif-Rack XS Editor. Unless you have a yet unmentioned reason to still be using the Studio Manager host product. Studio Manager is no longer necessary since many years ago now...

This means you are still running the Editor version 1.3.0 (2009) or earlier.

The current Editor runs without the need for the Studio Manager host - on the Mac side it's version now is 1.6.6 (2015)

Please download Motif-Rack XS Editor Standalone/VST version 1.6.6 (12/3/2015) for Macintosh.

The Motif-Rack XS can only connect via USB to a computer host, you cannot connect a keyboard directly to the Rack XS via a USB cable - that will NOT work. Everything can connect to the computer or you can connect one of your keyboards to the computer via USB, and the other to the 5-pin MIDI jack on the back panel of the Motif-Rack XS.

You can then use the Rack XS's ability to be a "MIDI interface" for one external device to reroute the keyboard's MIDI signal to the Rack XS.

To be clear, you connect the Rack XS to the computer via USB.
You set the MIDI IN/OUT = USB.
The USB-MIDI driver will allow your computer to communicate with the Motif-Rack XS via "Yamaha Motif-R XS-1" (port 1), and your external MIDI keyboard connected to the 5-pin MIDI jack as "Yamaha Motif-R XS-3" (port 3)

So to play the Rack XS you set Port 3 as the Input, and set the Rack XS Port 1as the target.
Your second keyboard connects via its own driver... As input and the Rack XS Port 1 as the target.

Thanks so much for the reply. With your insights, I believe I'm a little bit closer to having a solid setup.

On the downside, it would appear that I still need Studio Manager running if I want to HEAR output from the XS Rack. Once SM is closed, I no longer get audio.

What's particularly strange is that when I play the keyboard, I can SEE them being pressed in the XS Editor app.

On the positive side, I believe I'm starting to understand Port 3. The rule I've established is "The Motif gets the Computer, everyone else takes the Bus!". In other words, the only necessary USB connection is for the XS Rack. Keyboard controllers and other sources of MIDI input must use the conventional 5-pin DIN connectors terminating at the MIDI In on the back of the XS Rack. Right now, that looks something like this:
Arturia KeyLab88 MIDI Out -> KeyLab61 MIDI In | KeyLab61 MIDI Out -> XS Rack MIDI In

Then on the XS Editor Setup, I just specify Port 3 as the Port 1 Out. The layout of this screen looks great, but it's been somewhat confusing for me. So for MIDI Keyboard In (monitor) I have Port 3. The layout then has this:
MIDI In MIDI Out
Port 1 --------- Port 3
Port 4 Port 4 Port 4

On the Motifator forum I posted a thread stating that my previous setup was causing very strange problems when using the two keyboards. The above solution has resolved this completely.

I'm pretty happy with the above setup, but if you feel strongly that removing Studio Manager from the chain will help matters, I'm happy to continue working on it.

Cheers,
Tony G.

On the downside, it would appear that I still need Studio Manager running if I want to HEAR output from the XS Rack. Once SM is closed, I no longer get audio.

No, actually you don't need Studio Manager. If you were still running a Yamaha 02R or 01V digital mixer that might be a reason to continue to run the Studio ?Manager. You'll have to trust me when I say the new Editor did not forget to allow you to route the audio so you can hear yourself - it's simply a matter of settings and routing.

What's particularly strange is that when I play the keyboard, I can SEE them being pressed in the XS Editor app.

No, not strange at all. That's a feature and shows MIDI signal routed that far, now you must setup to route the audio so you can hear it. This is very normal - it indicates that MIDI is traveling from the keyboard and is arriving in the program, you need to make sure the program is set to send the data to the Rack XS, and that the Rack XS sends audio to your sound system.

I'm pretty happy with the above setup, but if you feel strongly that removing Studio Manager from the chain will help matters, I'm happy to continue working on it.

If you are happy and it works - I'm a big believer in, that's a good thing. Don't go changing.

I can help you with the Rack XS but I would need information on your other devices to even know how they connect.

If you are trying the standalone/VST editor make sure it is the Motif-Rack XS - and not the keyboard Motif XS version. They look similar except for the logo (and how they work).

Let me know.

Sorry to bring it up again, but I had a thought and wanted to pose the question in this context.

It was stated more than once that I shouldn't need Studio Manager in order to get sound from my XS Rack via the KL88 controller, and I still do.

I thought perhaps the problem might have something to do with the Mac Audio MIDI configuration, since I never really figured out how to draw lines between devices. Well, tonight I discovered how to do this and completed the setup as best I could, but I still appear to need SM2 to get sound.

It's entirely possible that I didn't quite configure this correctly, so if you have any insights in this regard, it would be appreciated. In particular, I'm curious what the proper MIDI I/O connections should be between the KL88 and XS Rack. Right now, it's got a connection going from the KL88 Out to the XS Rack Port 3 In. I guess what confuses me is that the XS Rack is really connected via USB so not sure how to make another connection from the KL88 Out to the XS Rack Port 1 too.

I have other connections in the mix which I didn't want to bring up so as not to confuse the issue, but I understand that having ALL the info is super important, so I'll try to figure out how to post a picture of the Audio MIDI setup screen for you shortly.

Grateful As Ever!
Tony G.

Don't need to do anything with your Audio MIDI setup.
Don't really need to know the rest of your gear.

What I do need to know is the exact version of the Yamaha Motif-Rack XS Editor you are using currently. Thanks.
Current version for Mac is 1.6.6

Yes, I have Version 1.6.6.

I'm now working on an alternate solution which is to implement my FW16e interface. I've made some progress, and have questions, but will create a separate post so we don't stray too far from topic.

Thanks,
Tony G.

Hey Guys.
I just installed this software on my new iMac and had the same problem cited above. Fortunately, I still had my old Macbook Pro to compare the new install against, and discovered the answer I had been missing all that time!

On the MOTIF-RACK XS Editor, at the bottom-right, there is tiny checkbox under MIDI labeled "Thru". Clicking this allowed the audio to pass through (gee, makes sense now) back to my Motif Rack XS, and joyfully out the digital audio port!

Just thought someone might come along and read this thread, and didn't like that it had no happy ending.

Any they all played their Motifs...