Reply to Audio Interface help

Hey guys, its been awhile since i've been on this site but I knew you guys could help me out. I'm putting together a home studio for production of my own tracks and things of that nature, and was wondering what kind of audio interface would I need for a 49 key keyboard and maschine using Ableton? I just use my S4's audio interface when DJ'ing and using the maschine but this is gonna be just going to studio monitors and will be stationary. Thanks guys!