Richard Dobson wrote:
> 
> Zhenhai Lin wrote:
> >
> > Dear all:
> >
> > I am totally confused about MIDI.
> >
> > I wonder how I can play midi sounds on SGI. I heard soundplayer can
> > handle midi sounds on IRIX6.2( which is what I am using). I tried to
> > play and it says I don't have a midi port. So I configured a midi port
> > on my machine but it plays without any sound at all.
> 
> You will need the proper MIDI hardware, which may or may not be built
> in:
> look for a 5-pin DIN  socket hopefully marked 'MIDI OUT' - can someone
> tell us what the standard implementation is on the SGI?


Depends on the model. Indy will accept midi from a standard non-parasitic  (as
of irix6.2) Mac midi interface through its serial port. For csound midi work,
you need 3.45 or 46. 3.47 has midi bugs. O2 is another matter. You need an
Antona serial converter and I dont have it working yet.

> 
> >
> > So is MIDI an idea of controlling an external music instrument? Do I
> > really absolutely need some kind of external midi devise to play midi
> > sounds?
> 
> Basically, yes. MIDI is a communications protocol not unlike a standard
> printer
> interface; so, just as you have to have a printer attached to your
> computer in order to print something, you need a MIDI synthesizer (or
> sound module) to play a MIDI output stream. Where this comparison falls
> down a little is that it is possible to have a MIDI synthesizer on a
> sound-card which is installed in your computer - this has been
> common-place for years on PCs; what there is available for the SGI I
> don't know.

Irix6.2 and up have a full-featured software synth/sampler. Plug and play pretty
much on the Indy.

> 
> >Is it possible to convert to something that I can play just
> 
> > using SGI's speaker (such as first convert it to csound file...)
> >
> 
> This is now happening on the PC (Yamaha, for example - I don't know what
> useful web links to show), but again I don't know what might be
> available for the SGI.
> In practice, real-time polyphonic MIDI synthesis is  so demanding for a
> general-purpose computer that even a SGI O2 might creak under the
> strain!
> Really a MIDI sound module or synth is the most practical solution.

Well, table-lookup sampling, if done well is not terribly expensive. Synthesis
will depend on the complexity of the algo. For table stuff, I get 48 voices at
44k on the O2 before it shows any strain. There is no reason a fast Pentium or
PPC would'nt get similar figures.

Simple 44k non-interp oscilator benches for csound hover around 150-250 voices
for most hi-grade hardware. (604e, PII, R5ks...G3?)


-- 
________________________________________________________
Jean Piche
Universite de Montreal
http://mistral.ere.umontreal.ca/~pichej
http://www.musique.umontreal.ca/electro/CEC/