Hi guys,
 
I'm pretty VST advanced sound designer but I need your experience. I'm looking for some "sound driven" vst sampler/synth. I need a tool that modulates one sound based on another (base) sound's amplitude/volume/velocity. Something like "Mouth" by NI but not a vocoder but f.e. "The louder guys is speaking the louder/higher pitch f.e. chainsaw sample is played". If smth is not clear please aks me, and I'm waiting for your help of course.
 
Another thing I need is a tool that can mix/make a portamento from samples (waves f.i.) while I play them on different freqs on my midi keyboard. Dimension is really weak when it comes to portamento feature  but you can load samples into this.

SoundITI'm looking for some "sound driven" vst sampler/synth. I need a tool that modulates one sound based on another (base) sound's amplitude/volume/velocity.

How fine-grained is the modulation?  If it's in the range of tens of milliseconds or greater, you might be able to use one of several of the Fab Filter effects like Saturn.  Add an envelope follower, side-chained to the alternate signal.  Dial in no distortion (keep the Drive all the way counter clockwise), and modulate the output level with the envelope follower.  That might do the trick.

Here it is, search fabfilter twin 2. Check out the videos on youtube, it's pretty cool.
 
 
 

I am sure Reaktor could do it but programming Reaktor is not for the faint of heart. It would be worth searching the NI Reaktor user Libraries. http://www.native-instruments.com/en/community/reaktor-user-library/
 
XILS4 has envelope following, transient triggering and pitch tracking for external signals combined with an extensive modulation matrix where pretty much anything can be routed to anything else without distinction between audio and control signals. http://www.xils-lab.com/pages/XILS-4.html
 
Just by way of example of the type of bizarre routing possible you could modulate one oscillator with the input audio signal, feed it through a filter modulated by the pitch follower, ring-modulate the output of the filter with another oscillator who's pitch is being controlled by an envelope triggered by transients in the audio and control the volume with the signal from the envelope follower. Of course, just because you can does not mean you should.
 
However as it only has one audio input you are probably too limited to acheive what you are trying to do.

Wow! Thank you guys. You really inspired me with words "grain" and "side chain", and before I read all your ideas above I returned to Alchemy I was considering to buy and actualy it gives a LOT of possibilities, f.e. modulating pitch with velocity or modulate time that sample is started to play with anytning you want (velocity, mod wheel etc. ) in advanced tweaking tab. There's no side chain modulation (depending on f.e. signal strength or pitch) but anyway if I put both samples altogether and press midi keys it will give me similar effect, but only for one shot (not the way I described). Now I'm checking your ideas and will let you know. Thanks, I'm really surprised that you took this challenge :)

Ok guys, I guess alchemy does what I wanted in this thread, but I have one more question. I need a sampler with possibility of tweaking sounds that affect each other as they smoothly turn into the next one f.e. I assigned sample 1 do C1 to H1 and the next sample from C2 to H2 range and I need some effects (pitch, granular effects) to do some kind of a "portamento" between them, so every combination sounds different. I downloaded demos of : Halion 5 , MAGIX Independence and MOTU Match5 3 but haven't tested it yet. What do you think is the most advanced sound design sampler tool with the biggest amount of possibilities to tweak between samples?

I'm not fully understanding what it is you'd like to accomplish.  However, you may want to look at Kontakt for it's Authentic Expression Technology (AET).  I don't know of any other sample playback technology that does anything quite this cool.  Here's one place to read about it - there are many others:
 
http://www.soundonsound.com/sos/feb10/articles/kontakt4.htm

Ok guys, here's my question - do you know any VST plugin with side chaining possibilities to midi? This way I could do everything on Camel Alchemy parameters based on track's f.i. volume.

I don't know what you mean with sidechaining to midi. It seems a meaningless term.
Do you mean that you want to generate a midi parameter (continuous control message) based on an audio track's volume? You could use midiAudioToCC for something like that.

I suspect that the morphing between sounds is also possible in alchemy, you should ask on their forum http://www.kvraudio.com/forum/viewforum.php?f=32