[sdiy] MIDI HD

[Michael Zacherl]

Hi Neil, et al,
I've to say my encounters with and use of MIDI might not be particularly typical.
So far I didn't have to implement some sort of MIDI interface for a project like a sound module or such rather than 
being dependent on existing products of any type being connected to software like Max, Pd or SuperCollider in order to make it playable live.
OTOH I certainly do have quite some experience in performing live on stage with a purely voltage controlled analogue modular synth.
(and of course using it in the studio, but that's easy)

I think there is a lot of detail to take care of and the "problem" is quite manifold and from my POV it raises
some questions.

For instance, I recently saw the MIDI chart of a Moog Voyager, and it nicely has 14-bit CCs for all pots, which are all transmitted.
On the contrary, the Moog Minitaur also _sends_ 14-bit CCs, but the implemented range is 0-127 for any of this controllers.
Maybe it's for compatibility reasons to ..., oh well ... I don't know.

Also time is an issue:
For instance the Behringer BFC2000: 8 motor driven 100mm faders. The box allows you to send 14-bit CCs.
"Nice!", I thought, until I used it: the unit sends MIDI-data just every 20ms!
That's 50 updates within a second.
So if you do a fade over the whole distance within a second, which I don't consider particularly fast, 
it's a new value every 2mm. This renders the 14-bit CCs rather useless in many cases.
Granted, for what's in there this box is dead-cheap, but why bother and including a higher res ADC in the design and
"downgrade" it by making it that slow? Just marketing?

And regarding playing live (what I mostly do): the more interpolation, smoothing, filtering etc. on the receiver's side
is needed, the less snappy this respective controls feels when performing.

The also cheap Korg NanoKontrol2 is different: It is that fast that I can't tell wether it sends all values between
the sampled old and the new position and apparently doing the interpolation itself or not.
Some occasional value is missing, like 1,2,3,4,6,7,8,9,10,11,12,14,15,16,17,... so far I can't tell if the computer is 
to slow to capture all of the values or if they are really not transmitted by the Korg thing.
I tried with several programs, same picture throughout.
Everything limited to a 0-127 grid of course.

A major disappointment was the interface of the Haken Continuum:
Years ago the first issues came with a Firewire interface, while the current, "updated" product just has this DIN MIDI jacks.
The point is, internally it's really fast and hi-res (see http://www.hakenaudio.com/Continuum/hakenaudiooverva.html ),
it's obvious that Lippold Haken put quite some effort into the implementation of this controller,
but then squeezes all the data through that old type of interface.
As far as I understand it's again marketing: the focus is on the internal sound engine which is largely based on Kyma's algorithms,
which are more and more advanced with every new software release. Granted they sound really good to my ears, but hey that can't be all?!
BTW, it's really nice to play with the internal sound engine (a colleague has the big one),
but getting something controlled via the existing MIDI is a real pain.
Maybe we could abuse the I2C connection for the CVC... ?  :-\

Dave Smith (he should know) says here 
<http://www.youtube.com/watch?v=buVeoLnL3tc&t=471>
quite something about MIDI, but IMHO he's taking some shortcuts and IMHO not being very clear about some of his own points. 
IOW there's more issues mentioned in that couple of sentences than obvious at the first glance.
E.g. smoothing is not the problem, "that's easy" ... right. But what about the grid?
The filters tuned in semitones ... well, ok, that's a musical approach.
Richie Burnett's mail in this thread already points something out in this direction.

I had a look at the MIDI implementation of the Prophet'08: it's single byte CCs, providing a coarse 120 semitone range
for the oscillators including a fine tune control with a +/-50 cents range.
It's a compromise though since the beating per cent detuning doubles with every octave. 
At a a''' (#93) it's roughly 1.01Hz - how would slower beatings be achievable?  
What I don't understand: for the filter frequency it's a single CC but the corresponding NRPN allows 
a range of 0-164 in semitone steps. Hows that done?

Coming from the analogue modular I'm very much used to cross modulation and the like to create complex timbres.
Quite often the sound changes drastically several times with a tiny bit of movement of the pot.
I'm sure, even with a less coarse grid (e.g. 10 or 12bit) on the fine pot, I'm sure I wouldn't be 
able to dial in quite a number of sounds.

BTW, anybody ever implemented a coarse and fine tuning on a filter?

My point about using existing controllers is in a wider context than just controlling synths like, say, a Juno 60.
(just to make the point very clear)

IMO nowadays analogue electronics and the current implementations of high res audio dsp engines 
allow a very rich and detailed modeling of sounds. And I think that requires a lot of thought and 
effort to tailor existing controllers to somehow meet that kind of quality!

Hence also my continuous search for alternatives. 

	Michael.

PS: This is not my cup of tea, but interesting: http://www.endeavour.de/evo/overview.html


On 21.1.2013, at 20:01 , Neil Johnson wrote:

> On 21/01/2013 17:37, Marc Nostromo [M-.-n] wrote:
>> Yeah but there's only one pitch bend per midi channel. So it doesn't
>> really fit 'precision controller' in a wide sense.
> 
> Perhaps not, but there are thirty-two continuous controllers per channel that support 14-bit values.  How many do you need?
> 
> And since they support updates through two messages (one for the higher 7 bits and one for the lower 7 bits) I think you can actually get quite a decent update rate as you only need to send the upper bits when the lower bits over/underflow.
> 
> There is a separate question of how many bits actually make sense, but I can certainly see why Michael would find 7 bits a problem.
> 
> Neil




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