Under 2.6.0 it uses 100% CPU for a few seconds and then is automatically stopped by Renoise. The instrument does work properly under 2.5.1.
There is a demo version of this instrument at
Sonivox Soundstage
Confirmed. Obviously it’s strange in Renoise 2.6. (on win Vista)
When I hit a midi-key or computer-key, the VU meter on the VSTi GUI spikes, then after 2 or 3 seconds, Renoise’s cpu warning message appeares.
It works fine in other hosts.
Also I’ve tried “run as admin”, but the result did not change at all.
(Now, the Renoise main developer has been taking holidays about one week. So probably we cannot see about this problem deeply right now, sorry.)
Btw, what a huge file size…it needed about 2 hours for download. 
Note:
It seems that I can use this plugin normally by doing like below;
- Load this VSTi and don’t hit any key yet
- Open the Editor and select another preset sound (click the little white triangle to open the list)
So, I think that this problem is related to the initializing process.
Also you can see this initializing problem in another Sonivox libraly too. (for example, Banjo. though cpu spike doesn’t occur)
Does messing around with these settings do anything?
http://tutorials.renoise.com/wiki/VST/AU/LADSPA_Effects#Plugin_Compatibility_Settings
Hmm no, the result didn’t change at all.
Well, I remember that Density MK2 problem.
Though it’s more worse case (Renoise crashes), I guess that it’s also somewhat a initializing problem.
In both case, the VU meter on the VST GUI will be MAX.
Using Renoise 64Bit - V2.8.0 (Built: Mar 14 2012) - this issue has not been fixed ever since. The advice not to hit any key and then to change the preset in external editor DID help though.
It would really be nice to see this get fixed. It’s not so easy to remember how some plugins should be handled
I don’t know if it is possible to figure out what 2.5.0 did that changed in 2.6.0