FWIW:

(sample rate) * (bit depth) * (number of channels) = kbits per second

For example, 44 100 Hz, 16 bit stereo equates to (44 100 * 16 * 2) = 1411 kbps.

-Ron

Edit - Shannon I'll betcha that 705 Kbps file you mentioned was monophonic (ie. one channel.)