I'm not sure I fully understand what you're attempting to do. It seems clear enough - but maybe just making the suggestion, we can kick this around and see what the additional requirements you have may be.

From the high level - it seems you could replace the UR242 with MODX and connect your HS8 monitors directly to MODX's Main L&R outputs. If you needed any additional inputs (Mic, guitar, etc) you could connect these to MODX's A/D Inputs. MIDI I/O and audio through USB. Even external MIDI gear you can connect to the MIDI In/Out of MODX and address this from the PC using the driver's Port-3.

... but maybe you prefer the UR242's output stage to MODX and want to keep UR242 as your audio interface. That can work. Connect MODX's Main L&R outputs to UR242's line inputs 3 and 4 (on the back). I suppose you could use the front combo jacks - but I'd need to look at Input 2's details to know if this is best. Input 1 has that high Z switch so it is flexible. Your VSTi would use the UR242 as the audio interface - you'd hear the sonic results out the HS8s driven by the UR242. Anything you play with the keyboard keys or play through MIDI messages (from Cubase or otherwise) to MODX will also sound out the HS8s because you can route inputs 3 and 4 to the stereo out in Cubase. Anything can be documented.

Did you need split tracks with each PART on a different digital input? The UR242 path gives you Main L&R and not individual USB channels. That's the main rub.

That's not necessarily the end of the road of possibilities. There are other tools like ASIO4ALL or Voicemeeter (mixer) that can give different audio routing options to enable using more than one interface at a time. I would go to these options as last resort if latency is of any concern.

I bought a MODX8 yesterday, and would like to use it for arrangement in Cubase Pro 10 on PC.
In the past, I used UR242 soundcard as the audio interface, which connected the Speaker (Yamaha HS8,yes i'm a huge Yamaha fan:) ),preamp and midi keyboard.

Thank you very much for the question. It’s one that comes up often.

But now, if I use the MODX as the audio interface, then I cannot connect the preamp and speaker through UR242 any more.
Which means, if I want to record the audio from preamp, I need to switch the ASIO to UR242 in Cubase and then re-connect the speaker to UR242, since Cubase can only have one audio interface. It's very innconvenice...
If I use UR242 as the audio interface, I cannot use the sound in the MODX (it becomes a MIDI keyborad)..

Yes, absolutely correct. But it’s the computer that cannot have more than one interface at a time. Because of that inconvenience, this is an issue for many. But it is the way it works. The device that is acting as the “computer’s soundcard” must handle all inputs and must connect to the speakers.

If you can configure your studio so this change is not a burden, that would be ideal. You clearly understand how this works. But it can be a logistical nightmare in some home studios (and that’s the reality). And if you need to record multiple devices simultaneously—then obviously switching the principal audio device does not work.

The ideal situation is this: all sound making devices enter one audio interface device... from that device you do all A/D and D/A.

If you have a general workflow where you are not recording multiple musicians playing simultaneously, say it’s just you, then you might configure your system optimized to record the instruments in the following order: basic rhythm tracks (using MODX), then if you are recording microphone stuff (vocals, guitars, etc.) you can overdub those separately through the UR242

Do you need to configure one setup that accommodates the best of both worlds?
That is, be able to take advantage of the 10 audio Outputs of the MODX USB audio system and still take advantage of the exquisite preamp in the Steinberg UR242 for your microphone and other analog inputs... well, let’s take a look at some options...

I knew the MODX connect can synchronize the recorded MIDI between PC and MODX.
But it cannot do what MOXF can do.
MOXF can be used as a VST instrument and everything can keep connecting to UR242.
Can MODX do that?

MODX CONNECT memorizes all your MODX settings for the current Performance. What the “MOXF Editor VST” plug-in did that was different had nothing to do with keeping the UR242 connected simultaneously. The MOXF had an actual Editor (Graphic User Interface). MODX CONNECT still runs as a VSTi and because you are using Cubase Pro, you can setup the “External Instrument” routing that would allow you to do the same VSTi functions the “MOXF VST” allowed. (We can show you that).

What it allowed was a way to ensure that your MIDI Track data could echoed back thru to the hardware tone generator and rather than the audio going directly to the audio Outputs, this routing scheme would return the audio back to Cubase. It arrives through a special virtual Audio Lane (this is a “what-you-hear-is-what-you’re-gonna-get” kind of thing... this is exactly what happens with soft synth VSTi ...virtual audio is rendered as real audio by the EXPORT AUDIO MIXDOWN function in a separate operation. You monitor the VSTi as it responds to the MIDI Track events... audio is rendered separately.

Advantages of VST/External Instrument routing include: You can process the audio returning from the external hardware with VST plugin effects; because it is not printed yet you can monitor what it “will sound like” once mixed down. Cubase Pro allows this type of advanced routing (External Instrument). We can certainly help you set that up, as well. (But it does not solve the “audio interface” issue).

This External Instrument Routing also allows you to take advantage of the equivalent of the FREEZE function, same as plug-in soft synths. This is especially, helpful with the MODX when you want to include Multi Part instruments in your Project. This allows VSTi MIDI data to be captured/rendered in temporary audio files (and the MIDI data is kept muted). This has the advantage of allowing you to reuse your hardware for other MIDI duties. This gives the hardware synth the ability to exceed the 16 Part Multi-timbral Limit; you can have multiple instances of the MODX open at once.

But trust me, it does NOT get you around the issue of swapping audio interface devices when the goal is to take advantage of each being able to deliver audio via USB to the computer. Like the movie, Highlander, “there can be only one!” at a time...

As you will see, there are many ways to approach this: let’s start with the basic setup no device swapping...

Never changing Devices
Because the UR242 has four inputs, connect the Main L&R output of the MODX to LINE IN 3/4 on the back of the UR242. You will create a stereo Cubase INPUT bus and route it to a stereo Audio Track.

_ select the UR-242 as the audio device.
This setup will allow you to keep one audio interface and use the four inputs of the UR-242, and the stereo connection between the UR and your monitors will never have to be undone.
The MODX will use the UR as the audio interface. (You will not be recording the MODX via its 10-bus USB System... you are recording the MODX via the UR242 (channels 3/4)
You will be able to record both the MODX (3/4) and whatever you plug into Inputs 1 and 2, simultaneously and discreetly to Cubase.

Using the MODX USB out to record, but monitor through the UR242
By maintaining the UR242 to your Monitor Speakers, you can Switch the ASIO Device to the “MODX”. This will allow you to use the 10 bus flexibility of your MODX’s Routing, and you will monitor the audio of the MODX through the UR242. The MODX can Output audio simultaneously to its analog Outputs and to the USB (to DAW) — you’ll simply listen to the audio direct, while recording the USB Out.

This may not work for all workflows... but generally, if working out music tracks first (with MODX) and adding, via overdub, the analog Inputs to the UR... There are many different ways to configure the setup.

How do you most often work? (It’s a tough question because you may not have a set workflow... and that is the true advantage, and at the same, the biggest disadvantage, of such a flexible system.

Thanks for Bad Mister and Jason's prompt reply:D 😀

In the past, I used Cubase to do the arrangement with VST like kontakt (controlled by MIDI keyborad) and recording the guitar parts through the ur242.
Now, I'd like to add MODX into my workflow, which can replace my MIDI keyborad for VST controlling and provide some amazing sound from hardware.
I don't need to record the MODX audio and vocal at the same time, but I'm trying to make my workflow better and smoother.
Please kindly see which one is better:

1. Only use UR242 as the audio interface
It's the solution provided by Jason:) It's the normal way to connect all the synthesizsers with DAW.
In this way, I can't use the 10-bus USB system, which means I need to record one track's audio before moving to the next track. If I want to revise the recorded track, I need to go back to the MIDI track.... (I'm not quite understand the "External Instrument" issue.. I knew how to create an external instrument and make it works. But when I Freezed it (track A) and change the sound source on the MODX, track's sound change simultaneously, which means I cannot create track B for another on MODX. )
Another problem is that I can't hear the sound from MODX standalone at anytime if I don't create an external instrument, because the speakers are connecting to the UR242.

2. Use the MODX as the audio interface
The disadvantage is about the preamp and microphone.
Firstly, A/D input should have an internal preamp which makes the audio dirty, since I already has a better preamp.
Secondly, when I'm recording the audio by microphone I need to shut down the speakers and hear the sound from earphone, to prevent the howling. But I can only turn off all the output on the MODX at once.

3. Use both device as audio interface by Asio4all or vociemeeter
It's the perfect solution if it works...
However, neither Asio4all nor vociemeeter can recognzie UR242's 4 input and MODX's 10-bus USB input...

4. Connect UR242's and MODX's output to the Speakers, switch the audio interface as I want
I thinks it's a good solution...
I found the HS8 has 2 input, and then I connected UR242's and MODX's output to HS8 (4 cables to the HS8).
When I want to record guitar or vocal or use VST, I will choose UR242 as audio interface.
When I want to use the sound in MODX and 10-bus USB, I will choose MODX as audio interface.
The disadvange is the noise, which will become louder since 4 cables connected to the speakers.
Maybe I can buy a monior like PreSonus Monitor Station V2 to dicrease the noise from the cable.

Do you think plan 4 is better?
Maybe there is a better solution... Please kindly told me:p :p

Another suggestion for Yamaha is about the DAW remote control...
I'm living in China, which has a huge market of Cubase.
If MODX has a DAW remote functions, I think more people will pay for it 😀 😀 😀

Apologize for my bad English... Hope I clarify my point of views...

Thank you again!
Cesar

...problem is that I can't hear the sound from MODX standalone at anytime if I don't create an external instrument, because the speakers are connecting to the UR242.

That’s why you “monitor” through the direct connection between the MODX and the UR. You switch the ASIO Device in Cubase to the MODX — this allows you to record to Cubase via the USB Output. But in order to hear yourself you monitor the MODX via the A/D Input on the UR. Headphones connected to the UR will let you monitor the MODX.

What you cannot do is monitor any plugin effects applied to the MODX’s USB signal (during record).

Hey Chen,

it seems we are in pretty similar situation, I am using my MODX connected to the line inputs of my UR44 and my HS7 monitors are connected to the main out of the UR44. This should be almost as your Solution 1, however, I am using Cubase Artist and cannot create External Instrument, I am simply addressing MODX directly via its MIDI ports/channels. This setup was working great for me with my MOXF because of the Yamaha Editor that was available as VSTi... but this does not really work with MODX.
I really hope Yamaha will think about improving the MODX Connect to add more of what we used to have with MOXF, if not for the full editor, at least for the connectivity and routing!

I do not, however, use external preamp, which also needs to go to the Line inputs of the UR interface... In that case, some rewiring will be needed when you record thru the preamp, but still, in this scenario, as BadMister is pointing, you can swap audio interface in the driver and keep monitoring (listening) thru the UR - no need to reconnect the monitors when you change the audio interface!

As far as I can tell, this setup is best when I am working on old projects that have been started at 48KHz. One drawback of MODX is the 44.1KHz sampling rate. It is 2019, seriously, to put such a great audio interface in MODX and limit it to 44.1... unforgivable!
And then again, the DAW control for MODX, can we at least get a confirmation if it's on the To-Do list?

Chen, please note that your Solution 4 is NOT recommended, in the user manual for HS monitors it is explicitly said NOT to use both connectors at the same time! I am pretty sure this is only a precaution, because mistakes DO happen and you may blow your speakers if you send audio thru both inputs at the same time.

you can swap audio interface in the driver and keep monitoring (listening) thru the UR - no need to reconnect the monitors when you change the audio interface!

Thank you Kalin.
I'm actually using this solution now, but one problem is that the audio in HS8 became MONO when I use MODX as audio interface...
Do you have this problem?

I answered you above, please read it, it is not the same as suggested in other posts.

Using the MODX USB out to record, but monitor through the UR242
By maintaining the audio connection between UR242 to your Monitor Speakers, you can Switch the ASIO Device to the “MODX”. This will allow you to use the 10 bus flexibility of your MODX’s Routing, and you will monitor the audio of the MODX through the UR242. The MODX can Output audio simultaneously to its analog Outputs and to the USB (to DAW) — you’ll simply listen to the audio direct, while recording the USB Out.