In specifying an interface, you really need to determine what kind and how many inputs and outputs you'll need. Earlier, you mentioned that you do live sound and that you will be using a 20-channel Soundcraft mixer in your control room, with up to 16 mics. Using an outboard mixer can simplify (or, can complicate) things. Sonar has mixer functionality, and many audio interfaces also provide mixers for routing and controlling their inputs and outputs. So, you need to think about how you will work. You need to consider things like: Can you use the mic preamps in your mixer for all your mic inputs? Does your mixer have direct outs for some/each input channel? If so, then you may only need an audio interface with balanced line inputs instead of one with mic pre's. How will you provide monitoring for talent (the musicians) and in the CR? Can your Soudcraft mixer provide several monitor outs/mixes, or will you need to rely on your audio interface's mixer or Sonar's mixer for providing monitor feeds? This can factor into how many outputs you may need in an interface. Also, what effects (such as reverb for vocalists) will you need on your monitor feeds, and how will that be done? If you can monitor with fx through your Soundcraft board (or running fx or aux sends through outboard fx gear and then back through your board), then latency (from the audio needing to go through the interface and through Sonar and then back out through your interface) should not be of concern, but if you need to use Sonar for fx, then latency may be a signifcant concern. I could go on, but hopefully you catch my drift already. Recording in a studio is different from doing live sound. Might be helpful to sit down with your engineer and draw out a diagram of your anticipated audio workflow and what gear you can use for what. Hope that helps! =Goddard