In various places on the PC, why does my S70XS show as multiple devices, i.e. S70 XS - 1, S70 XS - 2, S70 XS - 3, etc.. (see attachment). When working on a DAW project that exceeds the 16 available MIDI channels, I've often wished I could use those other "devices" as additional sets of channels, if that makes sense. Only one set of 16 would be valid at a time, of course, but being able to define more than 16 instruments would be so helpful instead of having to make channels do double duty.

Why does the instrument show as multiple devices sometimes, and is it possible to somehow use those devices as described above?

The number after the device denotes the USB-MIDI Port.

A Port is defined by a MIDI Out and a MIDI In. You know that 5-pin MIDI system is both 16 channels In and a separate cable for MIDI Out. Well, USB is considered a multiple Port interface...
The USB-MIDI connection for the S90 XS/S70 XS has five, count them, 5 MIDI Ports. That’s 5 sets of In/Outs.

__ Port 1 - is the MIDI In/Out for the 16 Part multi-timbral Tone Generator that is your S70 XS. Use this for all music data (note-ons, tempo, controllers, etc).
__ Port 2 - is the MIDI In/Out that allows your S70 XS to function as a Remote Control Surface for DAW software like Cubase, Logic Pro, etc. This works only when the [DAW Remote] is active.
__ Port 3 - represents the 5-pin MIDI In/Out jacks on the S70 XS back panel. Rather than do nothing when MIDI I/O = USB, Yamaha allows you connect an external MIDI device here... it will arrive in your computer identified as “Yamaha S90 XS/S70 XS-3” (Port 3). And likewise anything set to Output from the computer on “Yamaha S90 XS/S70 XS-3” (Port 3)” will arrive at that external device (signal passes THRU the S70 XS without stopping!) the S70 XS is a MIDI interface for one external device.
__ Port 4 - is used exclusively for the Yamaha “S90 XS/ S70 XS Editor” it communicates with graphic user interface that represents the hardware S70 XS. When the EDITOR is Online it is on a 1:1 basis with your hardware... any changes made to the Editor appear in the hardware and vice versa, any changes made in the hardware are immediately reflected in the software.
__ Port 5 - is used exclusively to setup and control VST plug-in synths that run on your computer. This port uses the “Yamaha S90 XS/S70 XS Remote Editor”... this Download comes with the “Remote Tools” - it comes with a couple of dozen plug-in templates and you can build your own if one does not exist for the plug-in you are using.

All of these functions require a discreet 2-way MIDI communication bus, that is why your computer sees the S70XS as 5 USB Ports via MIDI. The USB cable is replacing 10 5-pin cables.

The port 1 is what you need to make music with the S70 XS’s own tone generator. It has but one set of 16 MIDI Channels. If you wish to break the 16 channel limit, you do so as described below:

By the Numbers
If however, the number is a pre-fix (appears before the device name:
1-Yamaha S90 XS/S70 XS-1” (Port 1) this “1-“ out front, indicates the first instance of the S90 XS/S70 XS...
When you setup to use the synth as a VST (Virtual Studio Technology) routing, you can open multiple instances of the S70 XS VST.
Each would communicate via 16 MIDI Channels, and each would be identified by the number in front of the device.

Much like any VST soft synth, setting up to use the S70 XS as a VST means you can open multiple instances of the S70 XS...
YES, that’s correct! How? You ask, “I only have one S70 XS!?!”

You can setup and use “1-Yamaha S90 XS/S70 XS-1” (Port 1)“ and do the first set of 16 recordings....
You can then FREEZE (render temporary audio tracks that allow you playback the data intended for those first set of 16 Parts. The MIDI data is ‘frozen’ and muted... you playback an audio rendering of the first set of data.
This releases your hardware for 16 more Channels of data using a second instance: “2-Yamaha S90 XS/S70 XS-1” (Port 1)” as your second S70 XS VST.

You can then FREEZE these 16 (render as temporary audio tracks, these 16) freeing your hardware for yet another S70 XS VST... “3-Yamaha S90 XS/S70 XS-1” (Port 1)” and so on...

Link: Official S70 XS Download Page

Link: S90 XS/S70 XS Editor VST

Hope that helps.

See http://files.keyfax.com/download/S90XS/WinUSB_SM_Cubase.pdf page 2.

It shows -1 through -5 is normal.

-1 is for the tone generator MIDI.

The next page of the above document (page 3) shows "-2" is for remote DAW control ("remote devices" ).

The next page of the above document (page 4) shows setting up port "-4" in the editor.

Here's some better documentation from an old post from Bad Mister
Source: https://motifator.com/index.php/forum/viewthread/469746

Additional info
Port 1 is music performance info: Note-Ons, controllers, tempo
Port 2 is remote control surface info only. When your S70 XS is in DAW REMOTE mode and the SONAR Remote Template is selected, you can control Sonar from the front panel of your keyboard
Port 3 is the port that allows the 5-pin MIDI jacks to act as an interface for an external device
Port 4 is reserved for the VST Editor
Port 5 is reserved for the S90 XS/S70XS REMOTE EDITOR which let’s you setup the keyboard to control other VSTi’s you may want to run in your DAW. it comes with 50 Template locations per bank… Many if the most popular VSTi have a built-in templates, and you can construct custom control templates for all of your VST synths and store them for instant recall.

None of the -# ports are to give you more MIDI channels for local keyboard control. For that, you need a second keyboard.

None of the -# ports are to give you more MIDI channels for local keyboard control. For that, you need a second keyboard

You just need to read the post above, setting up the S70 XS VST allows for multiple instances of the synth.

Thanks very much for this information, it's just what I was hoping for! My old version (5.1) of Cubase is kinda pushing back (no audio from the frozen VST and additional VST's refuse to cooperate (open port error)) but those things usually straighten out if I poke at them long enough. Thanks for the Keyfax & Motifator links, Jason. Glad that content is still available. Cheers again guys, this looks really promising!

Hah! Got it working! Thanks again Bad Mister!

My"No Audio" problem was that I hadn't used the VSTi Setup (within the VST) to route the VST audio to my audio interface inputs.(the "Instrument doesn't send any audio to the application!" blurb when freezing the VST should have been a clue), The "Port Open" error was because I neglected to check a box that said "Unload instrument when frozen."

Jason, I'd never known how to use Studio Manager to access the S70XS from Cubase so it was cool to finally get that working with the help of the Keyfax doc, but since the S70 in that config isn't accessed via VST, I'm not sure that it helps me to use Studio Manager and now I'm a little confused about why/when to use the VST and why/when to use Studio Manager except that the VST supports multiple instances of the S70 and Studio Manager doesn't seem to do that.

Anway, thanks very much again, guys! You really helped me out and I learned a bunch of new stuff.