The Amp Envelope acts on the all Osc & Noise combined, but the Noise volume control is separated from Osc volume control. So you could keep the Amp Envelope open all the time and use LFOs or Envelopes 3/4 to control the Osc and Noise volume levels separately.
Unfortunately there seems to be no way to send the Noise to its own separate filter. But if you just want to approximate simple LP or HP filter without resonance, you could use an LFO or Env 3/4 to control the Noise Color.
That´s a good idea. However, applying ENV3/4 or an LFO (EnvMode) to NOISE Volume seems to sound different. IMO it`s not shaping like a real envelope...
I was just playing a around a pure noise patch...It's indeed weird. If you apply ENV3/4 to noise volume, it seems to be conflicting with the normal AMP ENV that will always impact noise volume and which cannot be bypassed. Unless if I somehow missed something. Even tried applying negative and zero modulation to the AMP ENV targeting the noise volume if that makes any sense. I would consider applying an LFO, specifically in ENV mode, depending on your needs.
It also sounds like you really need the OSC section to be independent from the noise section so why not use another patch and then layer them? For pure noise patches I usually use a vst, I don't want to waste one of the precious channels on my virus 
Now if you need common effects to be applied on both the OSC and the noise (for example a very specific phaser) you could also create a sort of "sub-patch" by controlling either manually or via a macro OSC VOL and noise vol in the OSC section...
You`re right. I experienced the same weird "sound" when applying ENV3/4 to NOISE Volume.... Yes, even in negative mode.... It´s even not possible to HOLD the NOISE with traditional sustain.... I don`t know what`s the reason why..
I´m working on some complex snare drum sounds. So i need the FM section of OSC2 and different envelopes for OSCs and NOISE
I didn´t expect this would be difficult on the TI2.
Having reconsidered your application, the thing is, if you apply amp env via the matrix it does not "offset" the amp env already being applied if you apply negative amounts; it doubles the application of amp env and by what I understand the amp env takes precedence over the matrix amp env in the signal flow.
It's not that sound design on the virus is generally difficult but your exact specific application may not be possible due to the inherent limitation of having a synth with a 95% fixed architecture... Judging by my other non-modular synths only, there is no way to completely bypass the amp env.
I know it's not really the same, have you tried the Noise FM mode?
Having reconsidered your application, the thing is, if you apply amp env via the matrix it does not "offset" the amp env already being applied if you apply negative amounts; it doubles the application of amp env and by what I understand the amp env takes precedence over the matrix amp env in the signal flow.
It's not that sound design on the virus is generally difficult but your exact specific application may not be possible due to the inherent limitation of having a synth with a 95% fixed architecture... Judging by my other non-modular synths only, there is no way to completely bypass the amp env.
I know it's not really the same, have you tried the Noise FM mode?
NOISE FM ist a good idea.. I will try this to see what`s possible regarding construction of more complex snare sounds. Yes, the TI is really perfect for creating any sound, as is the synth hardware layout! Because of it`s wavetables and endless modulation capabilities i was surprised that my mentioned application might not be possible.
