There is another that we have been very impressed with and use it for our acoustical measurements--that is the ESI U24 sound card. It's a 24 bit D/A and A/D conversion, has optical and toslink in and out as well as analog. It even uses balanced connections for the analog inputs and outputs, and is USB external (which was important to us because we use laptop computers). If anyone is interested we do sell these soundcards on our website. They are on the expensive side ($300), but worth it if you are really serious about audio sound from a computer. They are also very useful for recording live onto a hard drive, if you have the opportunity.