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
MA Hippo 122, (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), every option
Harman/Kardon 12-speaker System Option + Dayton HO D4 10" and PPI Ion 650.1 in sealed box
And many more car audio goodies in storage