Hi! this way of connect will force yr amp to double it output(let say 250wrms X 1 at 4 ohm) so if u let yr amp meet 2ohm at bridge ,u are asking yr amp to produre 500wrms x1 at 2 ohm(becouse 50%less resistence). If yr amp on that channal do not has so much power(500wrms) it would shout dow or turn over heated.

I really cant find the ohm rating for my subwoofer. If amp output 2 ohm and subwoofer 4 ohm then it wont overheat? Which amp will u recommend me?

This post has been edited by yuan415: Oct 26 2013, 09:29 AM

Wanna ask something about speakers also, im currently looking into DLS 226 and Alpine SPR-60, both 2 way coaxial speaker.
DLS spec: 50-20000 Hz, 92 dB, 50w rms,4 ohm.
Alpine spec: 65-29000 Hz, 88 dB, 50w, 4 ohm.
Which spec is better? I plan to buy 1 pair as rear door speaker.

Yes, it looks fine to power all 4 channels plus sub. This amp can handle 2ohm loads, producing rms350w, so it should be fine for a 2ohm sub up to 350w. If the amp is not rated for 2ohm output then that means it cannot handle it and it will overheat and shutdown. Note that you can actually use the sub channel to power multiple subs in parallel as long as the total impedance is not lower than 2ohm. For example instead of 1 sub@2ohm, you can also use 2 subs @4ohm with total power handling of both subs up to 350w.

Not true. It's already stated in the spec that the amp produces rms350W@2ohm for the sub channel, not 500w. Most amps would not be able to simply double their output when the resistance/impedance is dropped to half due to loss of efficiency. The sub channel also is not bridegable anymore since it's already a single channel.

Thanks for justification, is there any other alternative amps beside the model i stated? Maybe a cheaper one.
And can u advise for the above 2way coaxial speakers i mentioned? Thanks a lot

If you're on a budget, no need to upgrade the rear speakers since it's only for rear fill. You should focus your budget on front speakers instead because the sound staging and imaging should come form the front just like when you're watching a concert. So the front speakers should be the more dominant one while the rear is just enough to add ambiance effect. Many purist even do away without rear speakers at all!
If you still want to upgrade the rear, then just buy cheaper & less powerful one than the front.

Well for amp models, I haven't been following much anymore. Kinda lost track already coz there are so many brands nowadays with some popular brands already bankrupt while new brands come up. You can just google those popular brands first. If I'm not mistaken JBL has one 5 channels a bit cheaper but maybe also slightly lower spec, not sure.

My front speaker is currently DLS 226, the speakers is quite good and i plan to install the same pair at the rear, what do u think?will it affect the sq?

I think no need. Better use the money for the amp & sub.

Thanks for advice..so the alpine 4+1 channel amp is ideal for my components? Do u have other recommendation? Want to put underseat.

Should be fine. Maybe just need to be a bit more careful with setting the gain on your sub so not to overdrive it coz you said it's only 150W @ unknown impedance while the amp sub is 250-350w. A proper installer would be able to set accordingly.
No, I don't have any at the top of my head now since I've not been following much anymore. You can ask those sellers here like Howeichoo for other recommendations.

This post has been edited by 6UE5T: Oct 26 2013, 11:53 AM

The best is 2 ohm meet 2 ohm,4ohm meet 4 ohm,like y said amp output 2 ohm and subwoofer 4 ohm ,in this situation,yr amp this time see more resistance,so it output will be produce less watts.
p s: just for the fun- there are some amplifiers which could produce double the watts when these amp see 50% less resistance,some previous stereo 1 ohm could produce 4 times the power (when meet 1 ohm) compare to when this amp see 4 ohm.

Hello,By putting a pair of same (model) speaker for rear fill is the correct way to do ,because same cone paper & same magnet power (oz),same voice coil.But you need a processor to delay the real fill in order to get the right rear fill ambiance. Another option is use a 4 band eq (pre-amp),just to turn down 6 to 9 decible on midrange sound ,on that particular pair of speaker . those guys are correct ,you should invest on the up front (like they said concert)first,because the correct rear fill sound can not help your clarity,smooth,powerfull,sound linearity,toner,sound warm,dynamic and others.