[LAU] MIDI Routing/Mixing (Korg X50)

Dominic Sacré dominic.sacre at gmx.de
Tue Dec 9 22:44:32 EST 2008

On Monday 08 December 2008 00:20:36 Simon Williams wrote:
> Say I assign a synth pad and a piano sound to channel 1. Then I try to
> change the volume of the synth pad (using MIDI control 7), using the
> knobs on either the X50, or the MK (it doesn't matter which). What I
> find is that the piano, being on the same channel, also has its volume
> adjusted. Sure, I can use the MIDI filter feature on the X50 to say that
> the piano ignores volume changes, but then I can't fade out the piano if
> I want to.
> Anyone got any suggestions on how to overcome this? Currently the only
> way I can think of is to send all MIDI events via my laptop and get it
> to duplicate the note on/off events and send them to all the relevant
> channels. Is this my only option? Surely the X50 has a better way than
> this?

Well, that's what MIDI channels are for :) I very much doubt that the X50 
(or almost any other synth for that matter) can be configured so that one 
sound responds to note events on one channel, and controller events on 

I don't know the MK-461C. Does it allow you to split the keyboard into 
multiple (possibly overlapping) zones that send on different channels? If 
not, using the laptop to route/duplicate MIDI events is probably your best 

> Also, how well would MIDI cope with this? I have heard people mention
> that MIDI doesn't work so well if you send lots of data down it (like 8
> duplicates of the each note on/off message?).

Even if your equipment can handle it, it's probably not a good idea to send 
so many events for each note played. MIDI has a very low bandwidth
(31.25 kbit/s, assuming a standard MIDI cable with DIN connectors).
I may be oversimplifying a bit, but as a rule of thumb you can send little 
more than one MIDI event per millisecond.

Let's say you play a chord with 5 notes, and for each note 8 events get 
sent. Then the last event will arrive about 30 ms later than the first. 
It'll be easily noticable that the notes don't sound at the same time, 
which is even worse than latency alone.

> If this is my only option, does anyone know of any better MIDI
> router/mixer software? Currently the only one I know of is
> soundfontcombi, but it's not very flexible, and doesn't work so well
> with JACK's auto patchbay connections.

If flexibility is what you want, and you can live without a GUI, take a look 
at mididings (http://das.nasophon.de/mididings/). I guess it has a pretty 
steep learning curve, especially if you're not a programmer, but I'm sure 
it can do everything you need (and also a few things no one will ever 
need ;))



More information about the Linux-audio-user mailing list