I will hazard a WAG about the use of external sound cards.
In the speech recognition world, it was discovered that some internal
sound cards, especially those built onto the motherboard, were poorly
implemented and were subject to EMI/RFI interference, adding noise to
the analog signal ahead of the DAC - so we went to external sound cards
(in that venue they are affectionately known as "USB sound pods" - which
did the DAC closer to the microphone, and external to the electrically
noisy internal computer case - this was especially the case with laptop
computers - and in most cases, the problem could have been solved with
five cents worth of shielding.
So, I am thinking you are externalizing the DAC (Digital to Analog
Conversion) to avoid EMI/RFI issues.
Any traction? Do I win the cigar ?
My next guess would involve native driver issues... ;-)
==================== James -K8JHR ==================
On 8/10/2012 7:43 AM, Rick Dougherty NQ4I wrote:
, a computer with
USB sound card external interface(anybody know why), H
===================================================
|