Hello. I have done a project for a client, where all the instruments on the score are in treble clef. I have exported the project as a MIDI filed to send to him. He has imported the MIDI file into his music notation software and 4 of the instruments are showing in bass clef. The MIDI was taken from the score of instruments that are treble clef and the previous project I did for him didn't have this issue. Is there a reason for this? I have not done anything different to what I did on the original project, which worked perfectly.
MIDI knows nothing of clefs. It's just note numbers, the receiving program decides how to lay them out on staves.
What program is he using? If it can deal with MusicXML export that from Sibelius rather than plain MIDI. MusicXML contains layout information as well as just pitches.
Or it shouldn't be hard for the client to just change clef in a few of his staves.