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I have a very simple goal. I want to make a digital recording of myself practicing on a digital piano, play it back to myself, and share the audio with a friend.

My digital piano has a MIDI port. It cannot output raw audio, only MIDI. I downloaded a program called Xequence 2 on my iPad which captures my key presses and pedal presses and I can get a MIDI file out of it. (It also is capable of way more than what I need it to do.)

I want to generate an audio file using the MIDI file.

What I understand:

  • Xequence 2 is a sequencer, and it only works with MIDI signals. MIDI files do not by themselves carry sounds.
  • To get actual audio out of a MIDI file, I need a sound generator (a synthesizer?). Some sound generators sound better than others.

What I know how to do:

  • I can play the MIDI file back on my digital piano inside Xequence 2.
  • I can import the MIDI file into GarageBand and export an m4a file, which I can share (which is exactly what I need, but...)

What I want to achieve:

  • Use an alternative software to GarageBand. GarageBand ignores the BPM information in the MIDI file and I have to import the MIDI file as a “loop”, which I find counterintuitive.
  • Choose a piano sound I like.
  • Not use a free “MIDI opener” app or “MIDI-to-MP3 converter” website that has like one sound in it. I’m willing to pay for premium sounds.

What I’ve tried:

  • There are apps like Ravenscroft 275 which I can use to generate sounds “live” (I can mute my digital piano and use the app’s sound instead). While handy, this is not what I’m looking for.
  • I downloaded Synth One, which has way too many knobs for my purpose, but “import MIDI file” isn’t an option I can find.

I must not be Googling the right terms, because to me, “MIDI file in, piano sound out” sounds like a simple use case, but I can’t find a proper app / program where I can just give it a MIDI file, choose a piano sound, and have it spit out an mp3. What’s the proper terms for what I’m trying to do, and what options are there?

Michael M K
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  • *Convert midi to wave* is the term e.g. https://www.zamzar.com/convert/midi-to-mp3/ – Albrecht Hügli Jul 18 '20 at 06:35
  • Have you tried recording your playing i.e. key and pedal presses straight into GarageBand? Why do you want to have a MIDI file? What is this "raw audio" that your digital piano cannot output? Doesn't it have any audio outputs like headphones or anything that you could record as audio? If there's an audio output, you could record that into GarageBand. If there's no audio output, does it have speakers or what? – piiperi Reinstate Monica Jul 18 '20 at 08:42
  • Recording directly into GarageBand is also quite awkward. I just don’t want to work with GarageBand at all. I’m not sure how to capture the sound output from the speaker/headphone digitally. I don’t want to record ambient noise. The advantage (and curse) of a digital piano over an acoustic one is I can capture “pure” music. – Michael M K Jul 18 '20 at 13:41
  • Does the piano have a "line output"? Your iPad most probably has a line input? Electrical analog signals. It might be possible to use the piano's headphone output for this. You'll have to have an appropriate audio cable with suitable connectors. Search the manuals for "inputs" and "outputs". – piiperi Reinstate Monica Jul 18 '20 at 15:08
  • I’m sure it’s *possible* to connect the line out (i.e. headphone port) on the piano to the line in of a recording device (e.g. an iPad), I’m just not sure how. What cable should I get? Will the iPad recognize the digital piano as a microphone? I understand at this point the question is no longer specific to MIDI or digital pianos or even music... – Michael M K Jul 18 '20 at 16:51
  • Related [question](https://music.stackexchange.com/q/33521/2600). – guidot Jul 12 '21 at 11:07

5 Answers5

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Are you sure your keyboard can't output 'raw audio'? Isn't there at least a headphone socket?

Anyway, it certainly has a speaker! Why be so complicated? Use the audio recorder on your iPad or phone. Play the piano, record the sound. Done.

People get very purist about this. An electrical connection MUST be better than putting a microphone in front of the source. Well, yes... But try. You might be pleasantly surprised. And this is about conveying the music, not releasing an audiophile-quality recording.

Laurence
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    I don’t want an air gap between the sound output and the recorder. I don’t want to record ambient noise. I want to capture the output directly. If there’s a cable I can run from the headphone port to the iPad and capture sounds that way, teach me how? – Michael M K Jul 18 '20 at 16:30
  • I'm not a 100% sure (Android user, I would use a USB interface but of course Apple doesn't use USB). If your iPad has a 3.5mm jack, you need a Y-shaped cable from TRRS to 2x TRS (meaning you have a four-pole input+output jack on one end, and two three-pole jacks on the other, one for input, one for output). You can find those easily in the online storefront of your choice for a few bucks. The TRRS jack goes into your phone, the TRS input jack goes into your piano, and the TRS output jack is left open, and there you go. –  Jul 19 '20 at 12:05
  • Just searching for "TRRS" on any storefront should give you a good result. –  Jul 19 '20 at 12:06
  • And, again, literally any computer with a microphone jack or line-in jack should also be able to do this, with just a simple stereo audio cable. –  Jul 19 '20 at 12:11
  • A simple iPad is probably not a good tool for this job. But audio interfaces are available. – Laurence Jul 25 '20 at 17:42
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It sounds a lot like you need a Digital Audio Workstation, like Ableton Live. Which, admittedly, is a bit like opening a can of ravioli using a naval gun, but for importing a MIDI, adding a good piano sound (maybe try Dexed, a free DX7 clone), and exporting a MP3 you really only need a small subset of its functions and there are good video tutorials for the basics.

Unfortunately, Ableton costs a bit (or a lot, depending on the variant) of money, and the free alternatives I am aware of are a bit of a mess.

You might also just get a mic and record your piano with that, it'll be a more authentic representation of your playing than recording the MIDI and then re-rendering it with an entirely different instrument.

(You can also drop Xequence if you go for the Ableton option or for another DAW, bc capturing MIDI is another feature of a DAW, and you could even play a virtual instrument like Dexed in real time.)

  • Thanks! I’m not sure how to run a wire from the headphone port to the iPad and record the sounds this way. I don’t want to put a recorder next to the speakers because I want to avoid ambient noise. I’ll check out Ableton! – Michael M K Jul 18 '20 at 16:40
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    Is using a different “virtual” instrument any less authentic than using the sounds built into my digital piano? As I understand it, the piano is basically a controller/synthesizer built in one, and the sounds it produces might as well come from a MIDI file (I’m not losing information by saving the MIDI signals). Right? – Michael M K Jul 18 '20 at 16:40
  • When you are playing an instrument (even a virtual one), you have immediate audio feedback. So, over time, you develop a sense of how this instrument reacts to, say, the velocity of your key presses. And that means you develop a sense of how to impart a certain mood upon this exact instrument. When you play on one synth, and then reprocess the MIDI through another synth, you have a risk of losing this sense of immediacy, simply because the two instruments involved are not quite the same. –  Jul 18 '20 at 16:48
  • Ambient noise is a legit concern, but if all you want is to demo your playing to a friend or two, you shouldn't overestimate it. You can also get microphones with a directional characteristic (meaning, they record the thing they're pointed at) for fairly cheap (~50€). And as for recording with the iPad - I'm not sure what hardware you'd need for that, but I assume you have some kind of computer, and if there's some kind of line-in port, you could use that. –  Jul 18 '20 at 16:52
  • Good point on the immediacy. I’ll also learn more about line in / line out. Re: ambient noise is not that important for a quick demo — I agree. I guess I’m just being a nerd and want the data from the source, and using an air-gapped microphone feels like too much of a hack (and “there’s gotta be a better way”, etc etc). – Michael M K Jul 18 '20 at 17:02
  • I feel ya, but many professional recordings are done with a mic in front of a speaker (e. g. the speaker of a guitar amp) - because the speaker actually is an important part of shaping the sound. The main difference between your living room and a professional studio is isolation, to keep the ambient out. Don't be too hung up on perfection, that's not what makes great music great. –  Jul 18 '20 at 17:05
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For what it’s worth, I found a tolerable workflow that does what I want. Not endorsing any specific software / app mentioned here. Other brands are available.

  • MIDI recording: Xequence 2 or any other sequencer.
  • Signal routing: Audiobus or AUM.
  • Synthesizer: Ravenscroft 275 or many other options.
  • Audio recording / exporting: AudioShare

After recording the MIDI notes in the sequencer, have Audiobus route the MIDI output to the synth app, then route the output of the synth app to AudioShare. Hit record in AudioShare, then hit play in the sequencer.

If I don’t want to keep a MIDI file, I can drive the synth directly from the keyboard (instead of from the sequencer). I’m also ignoring the many, many options and features that music creators would appreciate but are wasted on me.

The entire stack runs on iPad and costs about US$50.

Michael M K
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You need Virtual MIDI Synth.

It is a "driver" for PC that simulates a soft synthesizer, it will appear as an output "port" in your computer.

It accepts SoundFont files. You would need a SoundFont bank, there are free ones around the net.

Load it up and play your MIDI, setting the output to go to the "port" - it has a function to "record" MIDI, which basically directly converts the sound from the SoundFont file into a WAVE file.

Ate Somebits
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Save the midi file from the keyboard on your hardware. Choose any software midi to wave (.wav or mp3). Done.

Albrecht Hügli
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  • OP's question is "which software can do this", basically, so this answer really isn't all that helpful. –  Jul 18 '20 at 14:50
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    I thought we are not allowed to make software recommendation. So any midi to wave program can do this. – Albrecht Hügli Jul 18 '20 at 14:53
  • Um, okay. I am mostly on StackOverflow and over there, questions like "which of these programs is the best" are not allowed but questions like "which programs can do this task" are. I'm sorry if I've broken the rules of this subreddit right off the bat, but in this case, any answer that doesn't actually name any piece of software seems fairly useless. –  Jul 18 '20 at 14:59