How do you change VSTi parameters with MIDI controller knobs/sliders?

[foxley]

I have an M-Audio Oxygen 49, and I'm running OpenMPT 1.26.05.00 on Windows 7 64-bit. So far the only thing I can control with my VSTi (I'm using Synth1 for testing purposes) is the pitch and mod wheels, and one of the sliders controls the volume for some reason. All the other knobs, sliders and buttons do absolutely nothing.

Is there a way to program VSTi's in OpenMPT to learn MIDI CC's and use them for certain things? I'm seeing you can set up Zxx Macros but I can't figure out a way to make them affect anything. Thanks.

[LPChip]

Hi there, and welcome to the Modplug Central forums.

Do you actually know how to do this? Have you been able to do it in other hosts, or are you completely new to all this?

The latter seems to be the case to me.

To control a parameter from a VSTi, a few things needs to be done. The host needs to know which parameter is controlled using which midi CC, and your midi controller's knobs need to be set to control a certain midi CC as well. By default neither are set, with the exception of the pitch and mod wheel, which use predetermined midi CC's.

Your first task would be to read the manual on how to assign a midi CC to one of your sliders or knobs or even buttons.

When I bought my SAMSON Graphite M013, to control parameters in my VSTi's, I ran into the same problem. Nothing happened. I found out that I needed to download a program to interface with it and program it that way (or use its buttons, but up to today, I still haven't figured out how that works)

[Saga Musix]

and one of the sliders controls the volume for some reason. All the other knobs, sliders and buttons do absolutely nothing.

That is because some MIDI CCs have a standard interpretation according to the General MIDI standard, and thus many synths are already set up to react to these CCs. In your particular case, that would be CC 10 (Volume). Most likely, all the other sliders are just set to modify CCs which Synth1 does not respond to rather than not being mapped at all,  so you can disregard what LPChip said about setting up the sliders.

Now there are two routes you can go.
Controlling the plugin directly
This would be suitable in a live setup where you do not want to record the outcome, and you only want to control only one plugin at a time. In this case, you can make use of the plugins' "MIDI Learn" features, which of course differs from plugin to plugin. In the example of Synth1, you would click the "opt" button, go to the "MIDI" tab and then select the parameter which you want to control and move a slider on your Oxygen 49 to learn the assignment between CC and plugin parameter. As long as the plugin editor is focussed, you can then directly control it with your MIDI controller.

Using OpenMPT's MIDI facilities
OpenMPT's MIDI Mapping solves the problem of mapping MIDI CCs to plugin parameters in a plugin-independent way. You create a pair of MIDI CC and plugin parameter to directly modify the plugin parameters. If you want to record the result to patterns, you click the "pattern record" button and the parameter changes will be recorded automatically as Parameter Change Events. Activate the "MIDI Learn" checkbox and move a slider to figure out the correct CC. Using this technique you can control several plugins at once without even opening their editors.