Re: Midi not playing note I expect

Hi,

On Monday 02 May 2011, Koenraad Lelong wrote:
> I think this is off-topic here, but I'm trying anyway.

Questions about making music with computers are perfectly on topic in this list, IMO. 

> I'm learning to play the Flemish bagpipes. I use noteedit to help me
> study my pieces. No problem here.
> In a while I have to play together with a clarinet and a sax. The piece
> I want to play had no lines for clarinet and sax, so with the help of my
> teacher I transposed some other instruments. 

NoteEdit can transpose automatically a staff any number of semitones up or down, using the menu option: Tools->Transpose. For instance, to prepare a staff for a clarinet in B flat, you can use the transpose function with two semitones up.

> Then I played the piece
> with noteedit. On some places it sounds wrong, so I told my teacher
> something was wrong. She says that the output of midi does not transpose
> sounds like clarinet or sax do. I was surprised to hear that so I
> investigated. I let noteedit play some notes and measured them with my
> tuner, e.g. when noteedit plays a G with a clarinet-sound I measure a G
> with my tuner, same with a sax-sound. Then I asked my daughter to play a
> G on her clarinet, and, to my surprise, I got an F on my tuner. Other
> notes "behave" the same. I had heard of this fenomenon but didn't
> understand it then.
> I tried the experiment with my tuner with rosegarden, with the same
> results, so I don't think it's the score-editor, but midi. I even tried
> different sound-fonts with the same results.
> 
> So my question is, why would a computer sound like a G when I ask to
> "play a G with a clarinet" when in reality a clarinet will sound like an
> F when the player sees a G on the score and presses the keys for it.

Because MIDI synthesizers don't really know anything about the real instruments which mimic, with more or less credibility. All they know is to produce sound with a frequency of 440 Hz when receiving a MIDI Note-On number 69, using the currently selected instrument on the same channel of the note-on event. The instrument itself is selected via a MIDI message containing for instance the identifier number 71, which corresponds to a clarinet sound only if the MIDI synth follows the General MIDI conventions. These are, among others, the rules belonging to the MIDI protocol.

> What I mean is, when I copy a score which includes clarinet and sax, and
> then I play it via midi, it will not sound like when that piece is
> played with real instruments. So what's the use of midi when it does not
> play the reality ? Or do you have to be a musicologist just to copy a
> score, let alone transpose one ? You would have to have two versions of
> your score : one to play with midi and one to play with real instruments.

Wait a minute. The score that you transcribed using your sequencer software is not the reality, it is only the correctly written representation of the music, following the rules of music notation for the instruments represented in the score. To render this score into real music you need a couple of trained musicians playing their instruments, following the score. If you want NoteEdit to render the score into correctly tuned music, you need to tell the program that some staff corresponds to an instrument that sounds transposed with respect to the written notes. This is accomplished using the dialog "Staff Properties" (menu: Staff->Voices) and changing the value for the "Play transposed" parameter. In the former example where we used two semitones up for a clarinet in B flat, now you need to
  change the play transposed parameter to -2.

Regards,
Pedro