I having been recording guitar with two sm57's through an audiobox 22vsl with audacity. For voice I have been using a Rode NT1-A. I have around 600 dollars to spend, and am interesting in simply increasing the sound quality and clarity of my recordings, especially for voice. I was thinking about buying a better interface but I do not have Firewire and really don't need more than 2-4 inputs. Would it better to spend the money on a quality condenser mic for voice? Does anyone know any good interfaces in that price range? Are USB to firewire converters legit? Also, would buying a mixer be usefulin acheiving better sound definition/control over sound? I'm sorry if these questions are dumb/ if I posted this in wrong place...You have guys have been VERY helpful int he past, so thank you.