Hi. Long time since I've been here... so I'm back to noob status!

I have a voice recording and I want to build / steal a filter that will add noise to it. For example, to add the sound of "wheezy" inhalations in between words (i.e. when the amplitude stays below a threshold for "long enough") and to add the sound of "rasping" exhalations when the dialogue is actually being spoken. This is all offline -- so multi-pass is fine.

so two things:

• could someone please point me at guidance on processing the voice recording to build the (?) envelopes (?) needed to control the breathing in/out noises
• anyone got a good baseline / outline from which I might be able to build the breathing noises?