I want to buy an audio interface for use with Logic Express I want something with two XLR mic inputs. My question is not about the mics it's about S/PDIF. I know what S/PDIF is, but wonder if I will want this later. I don't think I have a need for it now. I'm looking at the Tascam US-122L and the Tascam US-144. They both look the same except the 144 has s/pdif in and out. I'm wonder what I'd use this for in a small home recording system. The other interface I'm looking at are the e-mu 0404 and the e-mu Tracker Pre. The main difference again is the 0404 has S/PDIF What is s/pdif typically used for? I'm guessing for ripping sound off a CD or DVD.