Looking to replace front speakers. Input to help decide needed.
 

Right now I've got Alpine SPR-17C 6-1/2" with adapters.
They're good, but I'm looking to upgrade.

6-1/2" Coaxial 100WRMS 65-27kHz 87dB

I need help to decide...
6.5 with adapters or full 5x7/6x8?
Coaxial or components?

My goal is better midbass so you get a kick from the front doors as well as the subs.

Is going to the Alpine 5x7" SPR-57C going to be any type of upgrade?

I've been looking at Polk Audio MM or Infinity Kappa as possible replacements.

Leaning towards KAPPA680.9CS...
5x7 Components 90WRMS 40-35kHz 93dB

But the Polk MM6501 are tempting too...
6-1/2" Components 125WRMS 40-25kHz 95dB

I'm using the Polk MM 6501 woofers in my doors right now with 200 watts going to each side. They POUND! I have them running from 40 hz up to 4000 hz. Simply amazing!

You have them high pass filtered at 40Hz? What amp?

I'm using a DD S4 with 200 a side to those and 100 a side to the Hybrid tweeters.

Big thing if you want better mid-bass from the doors is to seal and dampen the doors - and I suggest re-inforcing the mounting area with MDF. Gotta make the doors more like a box :)

After that go with components - usually they are a better build and materials that co-ax's not to mention a better x-over usually. The big bonus is you get total control over placement of the tweeter for response and imaging.

If your in TO I'd go see Chase for the right advice on what speakers to put in and how/where.

Tried to do a simulation using WinISD to be able to see bass response.
Got T/S parameters from the Infinity website, and over the phone from Polk.
Also asked Alpine for specs on their SPR-17S but they never got back to me today.

Inputted the specs and set the same box size across all, and set the input signal to the max RMS rating of each. This is what I got. Mean anything?

Biggest gap is 106dB for the Kappa 60.9cs 6-1/2" components compared to 109.5dB for the Kappa 682.9cf 6x8" coaxial at 100Hz.

Based on this info, the Kappa 6x8" coaxial should have the greatest bass response... or am I missing something?

We also have a new entrant into the race...

Rockford Fosgate Power Series T1652-S 6.5" Components

...how does that stack up against the other two?