Hey iam new in the modular world and i plann a allrounder rack.
I have a problem with stereo.
I go from wavetable Vco to a stereo mixer to mix the Osc and Sub Osc to a L R signal and go into the Black Dsp 2.
Here comes the problem. i like the wasp filter but i there is only one mono jack input.
Can i go to from the dsp 2 to a normal mixer and mix it into one mono signal and than in the wasp filter or i do must take stereo filter.(not two wasp filter)
Can i mix the 2 signals to a mono signal? or is the stereo information lost?
Or can i go from the dsp 2 to a mixer with headphone output with a symmetric cable and than go into the wasp filter to have a true stereo signal?

Hope you can help me : )

Stereo can always be summed to mono, but you lose any stereo imaging. If you pass your stereo signal into anything mono, you lose stereo. The bigger question is what is and isn't stereo in the signal path?

Your typical VCO is usually mono. You can plug a mono signal into a stereo mixer and you'll get your mono audio coming out the left and right outputs (assuming you're not panning it left or right). But that's not true stereo. To be "true" stereo there has to be some difference between what's coming out of the left output and the right output.

Does the filter need to go after the Black DSP 2 or can it go before it?

VCO> Mono Mixer Input #1
VCO Sub >Mono Mixer Input #2
Mono Mixer Output > Filter Input
Filter Output>Black DSP 2 Input
Black DSP 2 Left Output> Stereo Mixer Left Input
Black DSP 2 Right Output> Stereo Mixer Right Input
(all assuming that the Black DSP can take a single channel input and apply stereo effects to it with the original input being panned dead center)

If you have a VCA like the Intelligel Quad VCA, you can trigger two VCAs with just one voltage. You can tap the fourth output as a summing mixer and then into the Wasp filter and then the Wasp into the Black DSP as described above.

If the filter has to go after the Black DSP 2 then you can't get around needing two filters. You'll also need to split any CV so it goes to both filters if you're modulating any part of the filter.

Also, always treat audio signal paths in a modular environment as singular, mono paths. So if you have a stereo signal at any point, everything from its outputs on has to be treated as if you were dealing with TWO mono signals. If you combine these back down again in any way other than through more stereo devices, you will have a mono signal as a result. If you keep that rule of thumb in mind, and don't look at a signal as a "single stereo signal", it becomes a bit clearer as to what's going on. Ronin's example above is quite correct, especially that last part regarding outputting the Erica DSP2 into two filters with ganged/matched modulation (or not ganged/matched, if you want to impart more difference between your left and right channels).

Duudes biiig THX for your answers. You helped me a Lot : )))

I go from the Vco to the mixer to mix the Osc and Sub Osc to a mono signal than in the wasp filter and then i multiple it to two mono signal to go into the black hole and from there into attenuater and interface to record them in true stereo : ))

Yupperz...that's how you do it! Just keep in mind that rule of thumb about audio paths, and you'll be able to go totally bonkers with stereo patch creation.