Originally Posted by Desertdan
Been reading a few posts, esp from VP Electricity and I am now more curious. It seems that a few 5.25's will fit in front doors, but am wondering if that is best route. A bigger driver will (all else equal) play lower and allow the 8" underseat to play less frequencies that are directional (more like a true sub). If i am looking to upgrade without adding a sub in the rear, wouldn't this be the best approach?
Yes, you can get more midbass out of 5.25" drivers. But there is always a flip side. The larger the midrange speaker, the more directivity you will have with the upper midrange frequencies (look up "speaker beaming"). So if you install a component set with a relatively high mid/high crossover point, say 4,000 Hz or more, you may be missing out on some frequencies, especially from the driver's side mid, since it is pointed away from the driver's ear at a higher angle then the passenger's side driver.
Keep in mind, that the difference in midbass between a 4" and 5.25" driver can easily be made-up by the underseat midbass drivers. However, the "hole" in the upper midrange frequencies may not be possible to be plugged, not even with heavy EQ.
The ideal set-up in our cars, utilizing the OEM locations, is:
4" components in doors
8" dedicated midbass under seats
10" or 12" sub(s) in trunk
Or, use a 5.25" component system that has a low crossover point, somewhere around 2500Hz would probably work. I'm not sure if that exists, however.