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I've played a couple of tunes of my electric piano, and have recorded them as MIDI files. I would like to convert them to a WAV format, but I'm worried for the following reasons:

  • By first recording my music to a MIDI file, does this mean I have lost the finite quality that would be obtained by recording to a WAV file straight?
  • By converting my MIDI file to a WAV, would I be able to retrieve the details of my music (such as hard and soft notes), or is the detail lost forever after recording it as a MIDI file?

I would appreciate any help. Thanks.

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    How precisely did you record the Midi? Will your audio recording be made by streaming that Midi back to its original source instrument/keyboard, or…? In the simplest terms, recording of a piano performance as midi then playing back to the same keyboard & recording the result as audio should result in no discernible difference. How such as the sustain pedal responds to live vs Midi playback may have some impact but we'd need to know the precise keyboard to determine that.
    – Tetsujin
    Nov 16, 2023 at 11:10
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    @Tetsujin I was just worried that recording the music as a MIDI would remove the subtle differences (such as hard and soft notes) so that when I coverted it to a WAV file it would still sound slightly robotic and unnatural...
    – Insatiable
    Nov 16, 2023 at 11:14
  • Well, why don't you convert it and listen to it to see how it turns out. If it's good, good. If it's bad, you'll have to record it again, this time in .wav.
    – Divizna
    Nov 16, 2023 at 11:38
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    All you need to do is play the midi file through your keyboard. You should hear exactly what you heard when you recorded it, and you can record the output.
    – PiedPiper
    Nov 16, 2023 at 22:35
  • As has been beautifully explained by others, a wav file is as though someone was in the room with a tape recorder. A midi file is as though someone transcribed the music onto paper as they listened to you play. Dynamics such as hard and soft notes would require both that the midi "notation" supports such details, and that the "listener" (the computer in the keyboard) is sufficiently sophisticated to notice them. Someone familiar with midi could answer the first, the second would depend on, well, how much the keyboard cost probably! Nov 17, 2023 at 15:39

4 Answers 4

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MIDI is textual descriptions like a book. Letters and numbers. C#5, E4, G3. Instructions that can be read and misinterpreted in any way imaginable. Channel 2, channel pressure 45.

WAV is an audio recording, like an audio book. A recording of someone reading the text out loud or making noises, sounds of birds singing, the reader singing, burping. Sounds you'll have to guess where they came from.

By first recording your music as MIDI, you will be able to edit it like text, read and re-read it, perform it in infinitely many ways, with different instruments if you like. You can send the MIDI file to someone else, and they will make their computers perform it, or even print it out as notation and have a symphony orchestra try and perform the notes and control-change commands.

When you make an audio recording of a performance of your MIDI file, that performance will preserve... one performance of the MIDI file. You can even mix in the sounds of the audience booing at the performance. Every little nuance will be recorded and preserved. But getting the original notes and control-change commands that there were in the original MIDI file won't be possible.

If you have a few kilobytes data storage space to spare, why not keep a MIDI version as well as an audio recording of a performance of it. It may come in handy later, letting you edit it and make recordings of further performances. Or if you intend to be an audio book author, why not keep a textual version of your book as text, in addition to an audio recording of someone or something speaking?

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    Also, many keyboards are also MIDI instruments, and if the one in question is too, then you could route the MIDI back to it to get the very WAV that you would have gotten otherwise. (Whereas the reverse conversion is still not possible without some loss/fuzziness, even with today's AI-powered software!) Nov 19, 2023 at 14:27
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Depending on the MIDI setting and the keyboard in question, the MIDI file may contain a complete transcription of what you have been playing (or more exactly: what the keyboard used from your play to generate the live sound). However, the only way to convert it into a .WAV file sounding exactly like your performance is to record your keyboard when replaying the MIDI file. The best option would be to record its digital production rather than its audio outputs, but the keyboards I know just don't make the digital production accessible.

Of course you can try not using the keyboard itself but some other MIDI device or expander software. Depending on what you use, the resulting audio may sound better or worse than the original. There is also the danger that the MIDI data contains some information (such as registration changes) that are not generally understood by MIDI devices but just by your keyboard in particular.

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  • The digital output of a keyboard is not an accurate rendition of the sound. The DAC and speakers both play a part in determining the final sound you hear.
    – Mark
    Nov 17, 2023 at 0:12
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    @Mark But the DAC and speakers of the playback device of any recording also play a part in determining the final sound you hear – as do the characteristics of the microphone – so I don't see how the air gap particularly improves the situation beyond introducing noise.
    – wizzwizz4
    Nov 17, 2023 at 1:27
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I'm confused by this question because midi isn't really a sound format. It's a score format, so to speak. The tones are not recorded but really prescribed - they're notes for an instrument to be emulated by synthesiser.

So... in midi (unlike wav, mp3 or ogg) what you've recorded is practically a score documenting what you played, not the sound itself. (You can even open this score as sheet music in Musescore and probably similar programs.)

I'm not sure how detailed this score is and how close a .wav file will be to what you played if you convert it, but I'm afraid that the actual sound of what you played has never been recorded in the first place. If you've recorded it from an electronic keyboard, then the sound was also synthesised when you played, and it's probably possible somehow (more erudite people than me would tell you how) to use the same sample source for the midi to get the same result. But if it was an acoustic recording, I'm afraid the original sound is lost.

Sorry to be the bringer of bad news.

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To address a concern in a comment:

I was just worried that recording the music as a MIDI would remove the subtle differences (such as hard and soft notes) so that when I converted it to a WAV file it would still sound slightly robotic and unnatural...

For most electronic keyboards, the music probably exists as MIDI data from the start. Note, as piiperi's answer elaborates, MIDI isn't actually an audio recording; it's instructions that an instrument or computer program can create audio from. If your keyboard lets you export both formats, they'll probably sound identical when you play back within the electric keyboard, since it probably uses the MIDI data to create the .wav. But you could then take that MIDI file and load it onto a different instrument, or a virtual instrument on a computer, and play it back with a guitar sound, or organ, or sci-fi zap sounds. Some of these virtual instruments might not be able to reproduce the data in the same way; for example, on a pipe organ it doesn't matter how hard you push the key, so a patch emulating one might ignore key velocity.

For one more analogy: If we compare these files to a printed document with words and pictures, then a MIDI file is like a .docx: it has all the words and all the pictures, and you can take the file to a new computer and change the words and and pictures and their order and layout and then print it. A .wav file is like a PDF file: It interprets all that data and locks it into place in one final version. (Or maybe you could say it's like a printout, since technically pdfs can be edited on the full version of Acrobat...)

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    In my opinion MIDI file is more like a .rtf: It can contain almost everything but some information will be missing. For piano the most relevant is half pedal that is supported by many digital pianos but MIDI standard requires the damper control to be interpreted as on/off.
    – ojs
    Nov 16, 2023 at 14:34
  • @ojs - if the keyboard sends graduated pedal, the DAW should record & play it back. [Just checked back some old Disklavier recordings, which sends 'steps' rather than full 0-127 but the info is recorded & the Disklavier will respond correctly if not with 100% accuracy dues to the stepping.] i.stack.imgur.com/bepPj.png Also tested it will export & import as a midi file this way.
    – Tetsujin
    Nov 16, 2023 at 16:35
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    For most electronic keyboards, the music probably exists as MIDI data from the start. I think the core of the question is if this is actually true, that is whether e-piano internally processes notes with the same resolution (of timing, velocity), or better than the MIDI format, and if the resolution of MIDI format is sufficient in all musical cases. Nov 16, 2023 at 18:24
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    @user1079505 it is very likely that modern digital pianos internally process everything with more resolution just because rounding velocity to 7 bits and adjusting timing to fit MIDI protocol is extra work that does not make anything better. If the practical dynamic range of piano is around 30dB, it would leave 0.24dB resolution for velocity so I wouldn't rule out that the rounding gets noticed.
    – ojs
    Nov 16, 2023 at 20:11
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    Well, the PDF analogy is not completely accurate, as it still is an abstract description of content visualization. The fact that the same PDF is (usually) shown identically on different devices (or in printing) is just due to its specific nature, in reality it may not always be true: this isn't only about editability, but also because rendering may differ in certain cases (such as thin lines). A more accurate analogy is a rendered image of it (or its printout, as you note); other examples: an HTML page (MIDI) and a browser screenshot (WAV); vector images (SVG), and raster (PNG, etc). Nov 18, 2023 at 19:08

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