Need to sum VST to mono (VB3)

I’m going to be doing an open mic where I get just one mono line out to a PA. What is the best way to combine L/R from a VST like VB3 that doesn’t offer mono out?

I can bring a small amp - I’m thinking a Motion Sound KP100S or Aspen Pittman Spacestation v3 might help in this situation. Interested if anyone here has used one of those.

Try the dialing spread knob on the gui all the way left. Should give you mono. Also look at the output options.

Hi Corky,

Thanks for that info - I can try it at a practice I’m heading out to now. Will be using one powered PA wedge.

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Good choice. I play smaller gigs on a 12" powered monitor.

Isn’t there a mono Leslie cabinet model specifically for that situation?

There is a monaural type, I think I tried it once when I was doing mono. It was easier to dial the spread knob than set a new cabinet.

My suggestion: don’t mess around with your song files or the VST instrument settings, but solve this at the Cantabile configuration level:

  • create a completely new configuration of Cantabile (see this guide)
  • in this configuration, change the audio port configuration so that both left and right output of your “main speakers” (or any other relevant) output are assigned to a single output of your audio interface. You could also map both left and right to BOTH outputs (simply add another output in the “edit audio output port” dialog):
  • if you go for both ports (maybe you want to use one to your PA, another one for your personal monitor), the result looks like this:

Now, both the left and the right channel of “Main Speakers” are assigned to both your hardware outputs (in the case of my desktop PC, HD Audio output 1 and HD Audio Output 2). Cantabile will sum both channels before outputting them, so you have all your output summed to mono.

I regularly use this feature - all my racks and songs are set up stereo, but with my R&B band, I only get a mono channel for my keyboards, so I simply sum to mono on both channels of my Zoom UAC-2 and then use the left channel through a DI box to the desk and the right channel to a small powered monitor. When playing with my rock band, I have two stereo outputs (separate for guitar and keys) sent to the desk - from the same song files without having to change anything. I simply start Cantabile with the R&B or the Rock configuration.

Give it a try!




And then, there is that too ! :rofl:

Thanks Torsten :star::star::star::star::star:

If you do any summing just listen to what’s coming out- sometimes there are weird phase cancellation artifacts with some stereo plugins. Should be ok with VB3, especially set to minimum spread.

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Summing the vb3 to mono actually produces a very reasonable Leslie!

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I’ve been testing it out, and you are so right Adrian.

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Actually, I have been setting my VB3 spread to close to minimum anyway live- I figure either the PA is mono in any event or it’s going to be panning across the stage and I don’t really want that. I don’t like to take my rig full mono though because then it sounds like sh!t in my IEM.

My keyboard always sounds that way, but I suspect it has something to do with the keyboard player. :laughing:

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Thanks for all the great replies!

Corky’s suggestion to set the spread all the way left sounded fine last night.

I was hoping someone would provide the steps to reconfigure Cantabile to sum LR to a single output - thanks Torsten!

I never noticed the Monaural Leslie cab Fred, I will check that out also.

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I know I am late to this discussion, but I have this situation frequently and use this DI box:

  • Paul

This topic is now hitting home for me. I now have a Bose Compact L1 which will take a stereo signal from the mixer, but doesn’t seem to come through very well. I have tried the pan everything to the Left channel idea and that improves it a lot.

My only issue now is auditioning my sounds with my headsets in stereo and not getting an appreciation for what the mono experience is going to be.

The idea of having another configuration setup with the outputs forced over is very appealing. I am torn between that and adding a VST panning rack to mono which I can easily flip back to stereo.

Does anyone have any real world experience to add in before I commit?

The easy way (no fiddling with the song files) would be the dual config way (see above). Alternatively, you could add an “output” rack to all your songs and give it two states (“stereo” and “mono”). Configure the rack with a stereo width tool (e.g. Melda MUtility) so that in the “mono” state, the inputs get mixed to mono.

Then make sure that the box “let the parent song control selected state” is unticked:

Save the rack with your default state selected (e.g. stereo). Then it will initially load like this - but if you manually set it to “mono”, it will stay that way, even if you load a different song in your set list.

This way, there’s not need to re-load Cantabile in a different config to quickly audition the mono version of your song - simply change your “output” rack to “mono” and test it. But of course it means that you’ll have to build this output rack into all your songs…




Great ideas (as usual). Thx