Re: So round speakers sound better than oval, but by how much?
I use 6x9's in the back. I've had vehicles that use 6x9's in the front and as long as you use higher quality ones (over $80-120), you can get some very good SQ imho. 2 or 3-way coax. Its very hard to get that much midbass in anything other than a higher powered set of 7 - 10" speakers...cone area ftw.
'65 VW Bus
(2) PG Ti 12's, (2) Aura Sound 8's, (2) SoundStream 6.5 coax, (2) Alpine Type-S 6x9's [rear fill], MBQ DSC1500.1D, RF 501X
'02 BMW 330xi (AWD coupe)
Harman/Kardon 12-speaker System Option - sounds good =)