[sdiy] MIDI spec

[Seb Francis]

Ingo Debus wrote:

> Seb Francis wrote:
>  > Ingo Debus wrote:
>  >>I found that I can swamp *any* MIDI receiving device when I program a
>  >>simple CV to MIDI converter: just read the ADC and output the data as
>  >>MIDI CC in an endless loop. It needs at least a few milliseconds delay
>  >>in the loop to work properly.
>  >>
>  >>The receiving devices I tried include my Mac running Logic or
>  >>SoundDiver, and my Roland S-760 in MIDI monitor mode.
>  >>
>  >
>  >
>  > This sounds strange .. consider a big SysEx dump - this can be a
> really long continuous stream of data
>
> Hm, perhaps a long Sysex dump takes less processing power than many CC
> messages? Still strange that SoundDiver's MIDI monitor screws up too.

It could also be your MIDI interface.  I have an old OpCode parallel port MIDI interface, and this tends to crash at best the interface, and at worst the whole computer when you feed it big SysEx dumps.  Must also be a case of bad drivers I think.

Nowadays there are really good interfaces around like the Steinberg Midex 8 or Emagic AMT8 which (a) have plenty of channels, and (b) actually clock the data out themselves (i.e. the sequencer sends the data ahead of time, with timestamps when each message should actually be sent out).  This is much better than relying on a PC/Mac to get the timing right - even the fastest PC/Mac can have suprisingly sloppy timing through a normal MIDI interface (worse timing than a typical analog sequencer for example).

The disadvantage with these interfaces is that they are proprietary, so you only get the improved accuracy if you use them with the right sequencer.  Having said that though, my Midex 8 still works very well in other software using the standard windows drivers.

Seb