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

Jörn Nettingsmeier nettings at stackingdwarves.net
Mon May 18 01:20:31 PDT 2015

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 

Jörn Nettingsmeier
Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487

Meister für Veranstaltungstechnik (Bühne/Studio)
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