Thanks Florian and Kevin for the responses, it makes a little more sense to
me now. I've been sick a couple of days so I'm just catching up with this and
I'll give it a try tonight. I don't have an inverter but I'm going to try to trigger an
EG instead to give an acoustic instrument a new envelope so I'll just use the
inverted out of the EG. As I mentioned before I'm trying to experiment with the
concept behind the Transient Designer which is supposed to be a fun piece of
gear.

Regarding the vocoder, I find it's also quite useful as an alternate filter even
when you don't want full-blown talking robot effects. For example, patching
an oscillating vcf into the speech input lets you create filter sweeps that have
some of the character of the vcf but are subtly different as you can hear the
bands of the vocoder.