I want to be able to hear something different from my head phones than what is being played on speakers. So for example can something like this work: http://www.amazon.com/Vantec-External-Channel-Audio-Adapter/dp/B004HXGJ3S/ref=sr_1_4?ie=UTF8&qid=1375389412&sr=8-4&keywords=external+sound+card
and how does it compare to this: http://www.amazon.com/Sabrent-virtual-External-Adapter-USB-AUDD/dp/B00D69U1B0/ref=sr_1_3?ie=UTF8&qid=1375389412&sr=8-3&keywords=external+sound+card
also, if these external adapters can work what specs do I look for to know that they act as a second audio output source? Thanks!
and how does it compare to this: http://www.amazon.com/Sabrent-virtual-External-Adapter-USB-AUDD/dp/B00D69U1B0/ref=sr_1_3?ie=UTF8&qid=1375389412&sr=8-3&keywords=external+sound+card
also, if these external adapters can work what specs do I look for to know that they act as a second audio output source? Thanks!