Hi Conan,
Welcome to YamahaSynth.

When you connect the MODX to your computer via a USB cable you can communicate with that computer both MIDI and Audio data.
This requires the ”Yamaha Steinberg USB Driver” for your computer type (Mac or Win). This is dual driver that does both MIDI + Audio for your MODX.

Briefly, MIDI data is a series of coded messages that can be recorded, edited and played back to a compatible device. Much like a musical chart *represents* the music, MIDI data represents a musical performance. You cannot hear a musical chart, you need the instruments to recreate it. MIDI data is like the holes punched in a roll of paper, it represents a piano performance, but you must put that piano roll in an appropriate device for it to be decoded and turned back into audible sound.

Audio, in this case, is what we hear as a result of the instrument outputting signal that can be interpreted by your speakers and can disturb air molecules. The MODX can output both analog audio (signal that goes directly to your monitor speakers) and digital audio signal that can be documented in a DAW (like Reaper or Cubase).

Purpose of Each: MIDI/AUDIO
MIDI — you would record data as MIDI when your goals include notation, or you simply want a method to assemble your recorded composition. MIDI offers several ways of correcting your performance (wrong notes can easily be corrected as can questionable timing). MIDI gives the modern musician a method to correct and even change your mind about instrumentation before committing the performance to Audio.

Audio — is a more permanent, way to document your music. It is easily distributed to a wide audio. While only musicians are likely to own MIDI gear, if you wish to distribute your music among the wider world of ‘civilians’, you’ll need to, at some point, commit to a Mixdown that is committed as an Audio file.

The MODX can output a Stereo .Wav (ready to playback on a wide variety of consumer devices) or you can do what is called multi-track recording, where different instruments are routed to discreet Audio Tracks. This discreet, isolated track method allows for advanced processing and manipulation before committing the composition to a Stereo file (the common distribution format).

Virtual Audio versus Real Audio
What is virtual audio? You may know about VST (Virtual Audio Technology) - a Steinberg innovation, btw, as a way to include signals generated outside of the DAW environment. They can be routed through the DAW program, even processed by the DAW. Most folks see it as synonymous with soft-synthesizers, but that is only a bit of the story. It includes *routing* that supports synth programs, effect processor programs, external rack mount processors, and even external hardware synthesizers.

The word “Virtual” is used because rather than actually printing the Audio data from these sources to an Audio Track, you are allowed to ‘monitor’ (hear) exactly what it will sound like when you finally do render it as audio. So you are listening to a “live” signal. And in a separate process you *render* or have the program generate an actual waveform.

Soft synths and software effect processors (where the tone generator or effect processor is also on the computer) render the audio in just seconds. However, when you have setup your external hardware effect processors and external hardware synthesizers as “virtual” devices, you can take advantage of all of the routing and mixing functions that the software synths and effect processors can... the difference is that because the external devices are outside the box, signal must be routed from the DAW MIDI Track, to trigger the external device, which then outputs ‘real’ audio. You can monitor it and process it inside the box just like the data generated on the computer. When you go to render it permanently this must take place in real time. “Real audio gets rendered in real time”.

Setting up external hardware is an advanced function. In the Cubase DAW series, this is one of the main differences between Cubase Pro and the lighter versions. Cubase Pro allows for several types of advanced routing including setting up external Effects and external Synths in the VST scheme.

Sorry, I don’t know Reaper. I don’t know if it offers this type of advanced routing. But the good news is, you do not need to have the advanced routing to setup and render audio from your MIDI Tracks. You will not get all of the advanced routing possibilities, but you may not need those quite yet.

MIDI Track —> Tone Generator —> Audio Track

In general, you assemble the MIDI Tracks in the DAW.
You will be sending them to the MODX, the MODX tone generator generates the Audio signal, you direct that Audio Output to your DAW Audio Track. The MODX has 10 USB outputs. The Main Stereo L&R plus 8 assignables — the assignable USB outputs can be configured as mono or in odd/even stereo pairings. From within the MODX Performance you can route each Part as you require. From within a Drum Kit you can route individual drums to any output.

As you can tell, the MODX can accommodate many different workflows, from creating a simple 2track stereo recording, to one where you amass scores of tracks discreetly recorded. Yes, it can get complex, but please don’t let that scare you off. It is designed to flexible and to accommodate many different workflows and approaches.

There is no single way you must work, you can decide which best suits you. There are times you want to just quickly put together a recording to email to a friend, but there will be times when you want each instrument on a separate track (called “stems” ) because you are submitting tracks to Project being put together halfway ‘round the world.

Hope that helps with the overall concept.

I wanna use that midi file to be read by a piano vst. But it doesn’t want to read/play that midi, no sound at all even though vst works properly and can play other midi files, just the one initially recorded with modx can’t be used.
Something I could do here ?

Again I don’t know Reaper, but a DAW will allow you to re-route your MIDI to the device you want to sound.

Each device will output data designed to, once captured, play back the instrument it came from.

We mention that bit of obviousness, because it will matter how you recorded the data coming from the MODX.
IF you selected a piano that requires 4 Parts on the MODX... it is possible that you recorded four MIDI channels of data. This will, when played back to the MODX, work perfectly. However, could cause an issue when you attempt to trigger something that is only expecting one channel of data.

Here is a way to figure out what you need to do.
On the MODX, press [UTILITY] > “Settings” > “MIDI I/O” > set Local Control = Off

This disconnects the MODX Keyboard from the MODX Tone Generator. Now in order for you to hear sound, you will need to go to your DAW, Reaper, and receive the MIDI IN from the MODX-1 Port 1, and set the MIDI OUT to the device you want to sound.

If you want the MODX to sound, select “MODX-1 Port 1”, if you want to play the piano vst, select it for the MIDI OUT of this MIDI Track.

Thank you for the quick answer!!
Really appreciated

“Real audio gets rendered in real time”
Yes I found how to render it, I just thought I could render it like it usually does for vst tracks ( fast and without having to play the track)

For the second matter I still wonder why the modx piano or bass midi tracks ( both being only one channel in modx ) can’t be read in a vst track
Tried everything I could so far
But won’t give up
Thanks again

To use the Midi tracks in Reaper with a VST you right click on the midi track, then click Source Properties, then Check box that says "Send as Channel 1" then they will play in Reaper. If you notice the first track will play but not the ones after that because they are not on channel 1. I think the MODX outputs on different channels. I would make a new project, or at least copy the midi track so the original stays the same. I just happened to find this out after trying to check my Midi files I backed up from the MODX. I haven't hooked up my MODX to Reaper yet. hopefully it's not a nightmare.

"Clarify" I think this only works on Midi tracks that are broken down. If you have multi instruments on one track you will need to break them down in separate tracks then right click on each track. I take the Midi files off the usb drive from the modx, when I import them in to Reaper it asks me if I want to import multi tracks or single tracks. I always check multi for this reason. To break them down if you already have them in Reaper right click on midi track, then click "Item Processing" Then click "Explode Multichannel Audio or Midi Items to New One Channel Items. Hope this helps.

Thank you William for helping 🙂
Haven’t been online for long , just seeing your answer as I’m posting something new about c and f# on whole keybed that suddenly stopped working:(