edit: Click here for some quick examples (mono bass, cheesy home organ, chip square lead and a wobble saw lead)
edit2: See here for updated instrument pack
Just downloaded the new beta. Epic update guys, well done.
With the new features of the sampler it is perfectly possible to emulate synths natively. This is very useful for those of us who use Linux where VSTi’s are lacking.
Map both across the entire keyboard range so they play together (don’t forget to loop them!).
Then modify the sample parameters for one of them as you would with a multiple oscillator synth (add a pitch offset, a bit of detune etc).
Set the NNA to something appropriate (cut/note off would make a monosynth, continue for a polysynth etc)
Then add an appropriate volume envelope (emulating the ADSR on a synth, although you can be much more advanced in Renoise).
Then add a filter envelope if you wish.
Finally maybe a little LFO or follower on volume/cutoff/resonance to add movement. [There is a limitation here for which I am opening a bug report for]
Enjoy your new synth!