Well, I'm driving a Perdana V6 with all the stock speakers and HU. Recently my 2 rear speakers seems to be broken. At first, there were some of those "pecah" sound but after another 2 weeks, there were just totally no bass at all.
So after deliberating for some time, I've finally changed those 2 broken stock speakers to Kenwood's KFC-6970ie (4-way speakers). Wasn't too sure how good it is since I'm a noob in these things. I've also added a pair of MIX (should be cap ayam) tweeters which comes with crossovers. The trebles now sounds good, even better than before with the 2 new tweeters in front and also the tweeters in the 4 way speakers in the rear. However, the bass sounds too weak.
Did I missed something? What else can I do to improve the sound, especially the bass. I wasn't planning to add a subwoofer but if that would help a lot, I guess it's do-able. Besides those changes, I've added nothing else so far. I'm prepared to spend around RM500 to RM1k. Can some of the sifus here give some suggestion? Btw, I'm in Kuching.

Hmm, if the polarity was wrong, would it have work at all?

The sensitivity of the speakers are stated as 93 dB/W/m. Is that highly sensitive or not?

The 4-way actually refers to "a 6" x 9" (153 x 229mm) Pearl-Mica injection-moulded cone woofer', "a 70mm paper cone midrange", "a 20mm balanced dome tweeter and two 20mm dome super-tweeters". By the way, I've tried several combination of settings on the stock HU, mostly with the treble at "0" or even negative and the fader between "R1" and "R2" but it still sounds a bit weak.

Was considering getting a new HU and an amp too but budget a little tight at the moment. Need the cash for something else. So may only be getting one of these and the other one will have to wait for a few more months. Any advice on which one to get first? Besides the Eclipse, any suggestions for good HU around RM1k?