Hi guys I have just replaced my HU with an Alpinestar one and connected it to OEM amp with MOST adapter and discovered this is not a good sound quality option as the OEM amp is not a good match to the new head unit.

I now want to replace the OEM amp with an aftermarket one and there seems to be a variety of ways the speakers can be paired up to the different channels.

The car has 10 speakers as follows:

1. Central front speaker,
2. Left front dash tweeter,
3. Right front dash tweeter,
4. Left front door mid range speaker
5. Left front door mid woofer.
6. Right front door mid range speaker
7. Right front door mid woofer.
8. Left rear speaker
9. Right rear speaker
10. Rear Powered sub woofer. Has two 2 ohm speakers wired in parallel. Amp in this is apparently pathetic crap.

Some reports suggest the door mounted mid woofers are just 1 ohm impedance.
The front tweeter and the mid range door speakers are apparently wired together in parallel and the tweeters have a high pass capacitor wired in series with them.

There are many ways these can be wired up to a replacement amp.

Most head units have five line level channels fitted with RCA connectors:

Left Front
Right Front
Left Rear
Right Rear
Sub woofer.

A 3 channel 4 channel or 5 channel power amp could be used

Option 1 Three or four channel amp

Front Speakers
Connect the left front channel to the left dash tweeter and left door mid range and door sub woofer (dash tweeter and door mid range in parallel and then in series with door sub woofer)
Connect the right front channel to the right dash tweeter and right door mid range and door sub woofer (dash tweeter and door mid range in parallel and then in series with door sub woofer)

Rear speakers (these shouldn't need much power to drive them)
Connect the left rear directly to the left rear output from the head unit.
Connect the right rear direclty to the right rear output from the head unit.

Rear Sub woofer
Connect rear sub woofer to new amp. Remove built in amp from sub woofer and wire both 2 ohm speakers in series to be 4 ohms

Ignore front central speaker or if using a 4 channel amp experiment with connecting it to the 4th channel if you like.

In this configuration the mid woofers and sub woofer that requires the most power are driven from the power amp

Option 2 five channel amp

Front speakers
Connect the left front channel to the left dash tweeter and left door mid range and door sub woofer (dash tweeter and door mid range in parallel and then in series with door sub woofer)
Connect the right front channel to the right dash tweeter and right door mid range and door sub woofer (dash tweeter and door mid range in parallel and then in series with door sub woofer)

Rear speakers
Connect the left rear to the left rear speaker channel on the power amp
Connect the right rear to the right rear speaker speaker channel on the power amp

Rear Sub woofer
Connect to new amp. remove amp from sub woofer and wire both 2 ohm speakers in series to be 4 ohms

Ignore front central speaker





As you can see there are few options. Anyone got some first hand experience or insight on this who can make a recommendation?

 

With my setup i used a 4ch amp and ran the front mid/tweet off of ch1/2 and the door subs off of ch 3/4. I used the amp and headunit's crossover for the speakers.

I used the rear powered outs of my Pioneer double din head unit to power the rear speakers. I do have a subwoofer box and separate amp but it still sounds way better than stock when I run the system without the sub. In my opinion the stock amp is the limiting factor and changing it along with a head unit makes the system sound much better. I didn't hook up the center channel speaker. I could have used the front powered output of my headunit but after hearing the system without it I found it fine and not necessary to add.

I might decide to replace the door speakers but from what I've heard so far I don't think it will make a huge difference.

I used a 4ch JL Audio XD400/4v2 4ch amp, a JL 13TW5 for the sub powered with a JL Audio Slash600/1v3 monoblock amp.

 

That sounds like an excellent setup. I just ordered a five channel amp and will essentially do the same thing except I will remove sub woofers OEM amp and rewire the two speakers in series and run the sub off the 5th channel instead of a separate amp as you have done.

 

I did some measurements and discovered the door mid range speakers are only 1 ohm!

Not sure which amp will be safe to use to drive into this very low resistance load?

This also explains why when I tried connecting my aftermarket head unit to the original amp with a MOST converter (which only carries two channels) that the front speakers over powered the rear speakers). Figure the original head unit tells the OEM amp too supply more power to rear speakers to balance things out.

Front central dash speaker 2 ohms
Left front and right front: tweeter and midrange 2 ohms (as measured wired in parallel. Tweeter has high pass capacitor)
Left and right front door mid range speakers woofer 1 ohm Left and right rear speakers
Sub woofer ohms (not confirmed) but will measure it later today.