I am Also a Newbie to this field ..But I had discussed this matter with my university professor some days ago for another general discussion on noise sources .... and he opined that in order to separate our target signal ......If the source is in same ambient ...Just analyse the ambient noise first and then characterize it ..then analyse the original sound with ambient noise .....but this technique is applicable to only limited cases ....Just tale the case of a room in which there is a ceilingn fan that generates noise ......then two people talk while the ceiling fan works analyze the characteristics with ceiling fan (noise source only )and then with people talking +Ceiling fan on .......But this is a simple case .......