[LAU] 'crescendo' in MIDI notes

[confrey]

Hi to everybody,
I'm a new user of this mailing list; I use debian lenny and slackware on
my notebook; I'm a musician, but only since a few time I'm trying ti use
audio and musical software. I'd like - but I don't know if it's possible
-  to change 'volume' of a long note while a long note is playing, as I
can do it manually changing a slider's position. I don't know how to do
it, and which software I can use. I had a look to Rosegarden, QTractor
and Muse, but I found never about.
I'm a piano teacher,
hi everybody

confrey