Re: Describe differences b/w 2x12 and 4x10 speaker?
4x10" cab: 4 x (3.14 x 5 x 5) = 314"
2x12" cab: 2 x (3.14 x 6 x 6) = 227"
More bass requires more air, which requires more speaker. Theoretically, With 4 10" speakers, you have approx. 38% more area pushing air than with 2 12" speakers, so you will have deeper bass.
I say theoretically because speakers and cabs are not perfect devices, so differences in construction, materials, rating, cabinet, etc. between the 4x10 and the 2x12 cabs need to be taken into consideration.
Everything else being equal (which it never is), the bass of 4x10 cabs will generally sound "tighter" than that of 2x12 cabs.