So I have a tune composed in BIAB using all Real Tracks (no melody yet--just the chords and the form).

I want to record a melody I wrote for the chord progression/form using my Casio CTK-6000 arranger keyboard, but I want it to record audio, not MIDI, and assign the melody to a Real Track instrument. How do I do this?

Alternatively, I can easily record a MIDI melody to the tune, but is it possible to convert the MIDI melody to a Real Track instrument so that I have all audio?

(BIAB 2021, Windows 10)

No, that is not how RTs work.

Because RealTracks are made from live audio recordings, they cannot follow MIDI messages. Their individual notes/rhythms also cannot be edited in the Notation window or PianoRoll. They are only automatically generated by Band-in-a-Box or RealBand software.

if you are playing the midi, presumably you have the expression and phrasing you want so its a good perfromance you just don't like the sound.

what synth are you using? maybe a better synth would sound more like the real insrument you want.

some midi synths don't sound realistic. if you use sforzando you can load some very convncing sounds into midi.

what instrument do you want the midi to play and what synth are you using at the moment?

Your question has been answered (No, you can't; it doesn't work that way). Your real question is, how can I get better sounding MIDI? You have hardware and software options. Although I still use hardware, if I were starting new, I would go with software MIDI synths. The next question is, what's your budget? You can spend anything from free to thousands.

If this topic is new to you, PG Music has a web page called Dare to Compare. The examples used there are way out of date, but the concept is a good one: you get to hear different MIDI solutions to compare. It's a starting place to further research into MIDI software libraries. Look here: https://www.pgmusic.com/dare-to-compare.htm

And finally, when you get the sounds you want from MIDI, you can always record that track as a digital audio file, and treat it as such going forward in a DAW.

Hey, thank you to everyone, appreciate the responses!

OK, I get it, you can't use Real Tracks to sound a melody you've written.

I'll check out all the advice given and experiment with MIDI sounds.

I can also connect an audio cable to the line out on my arranger keyboard, instead of just using the USB MIDI, and try the keyboard's sounds through audio.

Obviously got a lot to learn. . .

that's why we're here - just keep asking if you need help

Some keyboards provides for both MIDI and audio over the USB connection. Unfortunately your Casio CTK-6000 does not. Per the +++ keyboard specifications +++ you can use the keyboard audio out connections to record the keyboard's audio output.

You will either need to use an audio interface for audio connections between the computer and keyboard or connect the audio outputs to the line in of your computer.