[SOLVED]ARP can't receive ext sound in reaper

[LBH]

Thanks for reporting back Pipalo. It's allways good to have a result in a thread.
I'm glad it works for you now, when using the missing link provided by lunker. That was a good and very velcome contribution.

I am confused, though -- is Reaper the only DAW that is handling external input this way?  I can't think of another VSTi that behaves this way in Reaper.  I did some follow up tests, and it appears that the channel 1/2 input is totally bypassing the Arturia VSTi internals, and being merged directly with the output of the VSTi.  Very strange to me ...

I don't know lunker. I think it's strange, if you can't use all the outputs.
I think each DAW is different.
Some DAWs like Studio One can't even route audio to instrument plugins, but only to effect plugins.
The last think i know about when it comes to Cubase is, that is has a sidechain possibility, but apparantly does'nt Arturias plug-ins external inputs is'nt avaible for that. But i have'nt tries my self.
Other DAWs have different ways to do this routing. Live use a sidechain possibility, but i don't know precisely how it works. I think Bitwig have a plugin that can route audio, but i don't know if or how it works in this context either.
I would still like to have informations about this. I don't understand why it shallbe so hard to get this in some cases vital information.

[Pipalo]

Reaper is supposed to be able to handle vsti as vst plugins,
and eventually it does.
But I don't think it's the way it should behave.

I went through some experiments as well,
and obtained the same results.
Getting a signal from 1/2 to 1/2, towards a vsti (Korg M1) that should not receive signal.
It still keeps the dry signal mixed out... same behaviour.

The case of the Modular is rather strange, as the signal gets in the vsti, gets modulated through it,
but the dry signal is still out there, like "on top of it".
Weird how the signal seems to be duplicated, in and out at the same time. Sounds fishy to me.

Anyways, your solution Lunker is nice and clean, and works perfect.