sequencing ALSA ports and clients

sequencing ALSA ports and clients

[Richard Bown]

Ok, earlier I sent this question to LAD but this is probably a better place
to be asking it.  Apologies if you've already seen it.

Basically I'm still confused about synth clients and ports.  My SBLive presents
four synth ports as default.  I create a port and subscribe or connect_to a specfic
SBLive port and client.  When I'm sequencing out to this port should I be multiplexing
among the other ports to exploit the synth's full polyphony?  Should I be adding to
the ports myself or can I get away with just using the one?  If the latter then why
are there four ports made available?  I'm sure there's a dunce's document someone
can point me to!

R
-- 
http://www.all-day-breakfast.com/rosegarden
http://www.bownie.com

Re: sequencing ALSA ports and clients

[Takashi Iwai]

Hi Richard,

At Wed, 10 Apr 2002 14:38:04 +0100,
Richard Bown wrote:
> 
> Ok, earlier I sent this question to LAD but this is probably a better place
> to be asking it.  Apologies if you've already seen it.
> 
> Basically I'm still confused about synth clients and ports.  My
> SBLive presents four synth ports as default.  I create a port and
> subscribe or connect_to a specfic SBLive port and client.  When I'm
> sequencing out to this port should I be multiplexing among the other
> ports to exploit the synth's full polyphony?

what do you mean exactly "full polyphony"?
if it means "playing tones with the same note number on the same
channel on the same port at the same time", then, no, emu10k1 and
sbawe drivers don't do this.
notes are exclusive on the channel, i.e. you can play only a single
note A on the channel 1.  but of course, notes A can be played on
different channels, or on different ports at the same time.

if a note on the port 1 is affected by another port, then it's a bug
of the driver (except the case when all 64 voices are exhausted).

well, it's not difficult at all to reimplement the driver to allow
multi-notes-on-a-channel, but i don't think it's common.


> Should I be adding to the ports myself or can I get away
> with just using the one?  If the latter then why are there four
> ports made available?  I'm sure there's a dunce's document someone
> can point me to! 

four ports are provided to support more than 16 channels.


ciao,

Takashi

Re: sequencing ALSA ports and clients

[Richard Bown]

Hi,

Takashi Iwai wrote:

> what do you mean exactly "full polyphony"?

I just meant getting your hands on the full polyphony of the synth.
Now I've realised that the sequencer interface (sensibly) treats the
on-board synth like any other MIDI device.

> it's not difficult at all to reimplement the driver to allow
> multi-notes-on-a-channel, but i don't think it's common.

No, that's fine.  I got a good reply from Matthias on LAD about the same
subject and as I said to him I think I'm still suffering under the old OSS
delusion that synth devices were still somehow "special" and the application
had to deal with its own voice allocations.  I was looking for a complicated
explanation to the behaviour I was seeing in my undoubtedly buggy code!

It took me so long to get my head around that OSS synth idea that I'm having
trouble letting go.

> four ports are provided to support more than 16 channels.

This is good stuff.  It all makes sense now.

Thanks,
R
-- 
http://www.all-day-breakfast.com/rosegarden
http://www.bownie.com