I need to record sound using 2 (or 4, eventually) microphones and then calculate the time delay of arrival of sound at the different microphone pairs. But first, I need a microphone array. And since I'm just starting out, I would like to connect just 2 mics first and calculate the time at which sound arrives at them. Can I do this using a sound card? And I heard sound cards will have typically one or two input channels. What are these then? http://www.ebay.com/bhp/external-sound-card-for-laptop The 'channels' mentioned along with the above devices are not exactly input channels?
The number of channels mentioned in the products you linked refer to output channels. A Dolby 5.1 system has 6 speakers (center, rear R/L, front R/L, subwoofer), thus 6 channels.
What you're looking for ist usually called audio interface and mostly used in music production studios. Manufacturers are M-Audio, Roland, Behringer (cheap), Focusrite and many more. You can get an overview here. From your previous question I assume that your application is speaker localization. Therefore you probalby don't need high-class converters and pre-amplifiers. If you're planning to use Linux it will reduce your choice.