MIDI files are to music what doc files are to word processors. MIDI files are a way of writing sheet music onto computer in a way which allows you both to see the written music and to hear/play it. It is possible to write a MIDI file using one program and then read it back or play it using another. It is also possible to edit and modify a MIDI file. As in most computing, it is not quite so simple, as a MIDI file produced by one program may not look exactly the same when read by another.
There are many internet sites which have free MIDI files to download. Most music players like Windows Media Player will play MIDI files much like they play MP3 and WMA files. The difference is that whilst MP3 files contain the actual music but in a digital form, MIDI files only contain the notes and the actual sound is generated by your computer. ie you are not hearing an actual performance but a computer generated version of the music.
In order to make and edit MIDI files you will need a program. I use Noteworthy 2 which costs about 50 USD and is available to download on the Internet. All of the MIDI files on my site have been generated with Noteworthy. There are more complex, professional and expensive programs eg Sibelius but these can be very expensive.
Using Noteworthy, it is then possible to create Adobe PDF files using a free program called PDF reDirect version 2. This works like a printer driver. You simply tell Noteworthy to print the music but select the PDF reDirect driver instead of your printer. The program will create a PDF and store it on your computer instead of printing it. It works a treat !
My main interest is the Guitar Quartet/Ensemble and there is very little high quality music written for this genre. I have therefore had to borrow music written for other instuments and groups. I look for possible MIDI files on the Internet first. Once found, I copy the file to my computer and open it with Noteworthy simply clicking through the default options (usually 4) and then finish. Noteworthy will then show you the music file. MIDI files with the extension .MIDI will need to be changed to .MID, ignoring the warning that programs may not be able to recognise the new file, in order for Noteworthy to read the file. You can then save the file and Noteworthy automatically saves it as .NWC which can be easily re-opened with Noteworthy.
It is alway worth spending time on the internet trying to find the best MIDI file that requires least work on your part to modify for 4 guitars. With baroque music eg. Vivaldi, Bach etc, there may be many versions available but some will be easier to work with than others.
A great source of high quality classical music, already in 4 parts, is the String Quartet. A good example is Haydn where all of his string quartets are available in an excellent MIDI form which Noteworthy can read in directly. It is simple to change from bass to treble clef for the cello part (delete the bass clef and insert a treble clef, select all the stave and then move the notes down 5 semitones) By magic you are now in treble clef and easy for the guitarist. Sometimes it is best to move the music up or down an octave (select all, control/shift/uparrow 7 times or downarrow). It is also easly to change the key to an easier key for guitarists to play in but each stave has to be done separately in Noteworthy. Occasionally you have to change a note when it is too high or low for a guitar to play, or move it one octave.
Often, when you read in a MIDI file, it can have many more than 4 staves. Reducing these to four can take quite some time.
Of course, you can start from the sheet music, as I have done with the Torroba Castillos de Espana.
There are quite a few tricks to overcome difficulties. The Noteworthy Website has a help page an user forum.
If you have any questions, feel free to send me an email. My arrangements are done for interest only. Feel free to use or modify them.
I have added MP3 files. These are only low quality as MP3 files are relatively larger and rapidly fill up my site quota but they may be easier to listen too with Android or Apple.