[Ardour-Dev] ardour4 vs midi control surfaces (slew rate limiting?)

Fernando Lopez-Lezcano nando at ccrma.Stanford.EDU
Wed May 27 10:04:34 PDT 2015

On 05/18/2015 01:20 AM, Jörn Nettingsmeier wrote:
> On 05/18/2015 03:41 AM, Paul Davis wrote:
>> There is a control which I believe is called "Threshold" which can be
>> used to control this. It is accessed by going to the "Surfaces" tab of
>> Preferences, and double-clicking on the generic MIDI entry there.
>> Different hardware needs different values for this - there is no
>> acceptable default.
>> On Sun, May 17, 2015 at 9:38 PM, Fernando Lopez-Lezcano
>> <nando at ccrma.stanford.edu <mailto:nando at ccrma.stanford.edu>> wrote:
>>     Hi,
>>     I've seen this behavior before in Ardour3 but it still happens in 4.
>>     Let's say I enable generic MIDI control, hook up a BCF2000 through
>>     the a2jmidid -e command and bind a fader to the master fader of a
>>     session.
>>     If I move the physical fader in the BCF2000 slowly all is good. If
>>     it goes beyond a certain "slew rate" the fader in Ardour gets stuck
>>     and stops reacting to (fast) movements of the physical fader. It
>>     only starts moving again if I slow down my movements and cross the
>>     last value stored by Ardour. It then follows the physical fader
>>     again until I move it too fast and it gets stuck again.
>>     Is there a midi command rate limit somewhere in the code? A
>>     preference I might use to turn off this behavior? Maybe a "feature"
>>     of a2jmidid?
>>     This makes it unusable for a "live" mixer situation (and I have to
>>     revert to Ardour2 which does not have this problem).
> There used to be a tick box "motorized" which would disable this locking
> threshold altogether and keep the control latched at all times. Check
> Edit->Preferences->Control surfaces->Generic MIDI (or similar). Don't
> know if it's still there in A4, but I think it is.
> Btw, there is a long-standing feature request to make this tickbox part
> of the session - last time I tried, it was not saved nor restored with a
> session.

Thanks for the tips!

In Ardour 4.x the setting is called "Smoothing" and is part of the 
"Preferences" -> "Control Surfaces" -> "Generic MIDI" (double click on 
it). Setting this to "1" disabled the weird jumps and stickiness of the 
MIDI controls.

As Joern notes, there is also a "Motorised" (sp?) checkbox in the same 
panel and regretfully it is not saved as part of the session (please 
please add this!).

So, by default, everything __almost__ works when you open a session that 
has been previously saved with those settings. If you move a fader in 
the Ardour GUI the fader in the BCF2000 moves to the right spot (and 
physical faders are initialized to the right values on session load). 
But if you move a fader in the BCF2000 the gui does not react. Clicking 
on "Motorised" immediately restores that behavior.

I switched to Ardour 4.0.0 as the playback engine for a concert last 
week and I had to open Preferences, Control Surfaces, Generic MIDI and 
click on Motorised to make things work for every session in the concert. 
Very inconvenient.

Worked fine otherwise!
Thanks, as usual!
-- Fernando

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