What will clip (distort) more as you turn up the volume?

2 ohm + 4 ohm speaker wired in parallel. (2 x 4/2 + 4 = 1.3 ohms)
2 ohm + 4 ohm speaker wired in series. (2 + 4 = 6 ohms)

 

Not many amps are designed to run with a 1.3 ohm impedance. Your amp will run hot and may actually blow with such a low load. At 6 ohm you'll probably get much less power out. Power = V^2/R. So, you'd get 6/1.3=4.6 times more power with 1.3 ohm setup.

So, that being said, for the same volume level, you'll have to turn the volume up on 6 ohm a lot more--so I'd suspect you'd hear more distortion with this set up.

If these speakers are designed for different ranges (i.e. a tweeter and mid) you're much better off/safer adding a passive crossover. If you're dealing with subs, make sure you find a 1 ohm stable amp and you should be fine with the 1.3 ohm setup

 

I have been trying to do some detective work on my audio issues. I apologize for anyone who has had to endure reading my multiple posts on this subject. I replaced my 4 ohm factory HAES dash speakers with 2 ohm Infinity Kappas in hopes of getting LESS clipping because they are rated at 93db sensitivity, but I am now getting more. Not knowing how the shop wired my head unit, I am trying to figure it out based on the symptoms. Part 2 of this exercise is trying to decide whether or not I want to try out the Alpine KTP-445, a 45 watts RMS power booster that installs between the harness and the head unit. This amp requires a 4 ohm load, which would be perfect if my door drivers and new Kappas are in fact installed in series (2 ohms plus 2 ohms for each front channel, and the stock 4 ohm on each rear channel).

 

I'm assuming that you don't have the factory Bose system with the separate amp and 4" mid and 1" tweeter in the dash?

Most head units are not stable down to 2 Ohm--you'd be at high risk for overheating the amp on the headunit. You have to figure out how things are wired. I'd bet that the shop wired the door and dash in series to avoid overheating.

The cleanest way to do this is to get a separate amp to power the whole system, but you'd have to rewire and that can be a pain.
I wouldn't trust that Alpine 445 unit to help a whole lot, but that's just my opinion (not based on any experience) but it may be worth a shot.

 

Well- I took the gamble and installed the KPT-445. It completely eliminated my clipping problem! And I have to say I am very very impressed with this little 180 watt amp. Clean sound and volume to spare. I'm telling you, my system sounds GOOD! I would love to pit it against someone who spent 3 or 4 times as much as I did.

Now, I just need to figure out where to house the KTP-4445 amp (which currently resides on the floor of the passenger footwell).

 

You have photos of installation?

 

Nothing to see really. Amp is mounted to the front wall of the bonnet, sub box behind the seats.

 

Nice sub-box, did you make it? I'm having trouble fitting a JL 8w7 sub behind my rear seats as its magnet and depth is too big to fit. I made a box to get it to fit but is an eye sore when I look back there, so i'm back to the drawing board to make it fit. Thinkin of doin my first fiberglass project but kinda hesitant to mess with that stuff.

 

Yes- I built that box. Speaker depth is the big issue which is why I put a Polk MM1240 in there. It is not a true shallow-mount woofer but is very shallow nonetheless. And 12". Boom.