I just received my 2 amplifiers, these are just the best amps I've ever owned. Pure power, clarity and quality. I'm using 1 to play 2 10inch Selenium mid-range speakers and 4 selenium mid-range horns. The other is being used to play one 12inch mid bass Selenium speaker and two pairs of Kicker KS20 tweeters and 2 Selenium pro tweeters. The music is just amazing. Only Kicker could make these gods of music. :-)

I have had this amp in my 2009 Accord Coupe w/ NAV for 6 months connected to the stock head unit and hooked up to 2 Cerwin-Vega CVMP6.5 on the rear deck for mid bass and to Polk Audio MM6501 up front for bass and treble with a separate amp for my 8" Sub.

There is more power than I can use and the sound is unbelievable! It required some tuning of the crossovers to my speakers, but it was easy to do and makes a great deal of difference.

Be sure to order a quality wiring kit and I also used mass loaded vinyl and adhesive backed sound dampening for the doors and dampening for the flat metal areas to reduce vibrations throughout the vehicle.

I had ordered another amp first but it wasn't compatible with my head unit. After working with their tech support, I was able to replace it with this. Sonic Electronix was great during every aspect!

I'll definitely purchase from Sonic Electronix again!
I only gave a 4 for durability because I have only had it 6 months, but so far so good.

I bought this amp because of the name, it's pushing four 5X7 infinity kappa speakers in my 2010 ford explorer sport trac, let me say the clarity it plays at high volume is really sweet, if you are looking for clarity at loud volume this is the amp for you, i almost forgot to mention the amp runs a little hot but this is how it's design over all i love it and recommends it.

This is the amp you want if you want clean power. I had an Eclipse four channel that had a channel go out. The new ZX 650.4 has taken my speakers to a new level. I have Diamond components in the front with MB Quartz in the doors of my 2004 Navigator. I had a custom built double 12 sub box firing down with Diamonds D3's in the rear hatch. Alpine head unit and the system is loud, but VERY CLEAR. The amp is a vital part of your system and you will not be disappointed.

I bought this amp to power my four Infinity KAPPA 6x8 coaxial speakers in my 2011 Ford Focus. It sounds awesome and gets super loud! If you want super clear quality and super loud while not distorting, then get this amp! My gains on mine aren't even half way and it sounds so good. The birthsheet for mine said 685W! That's outstanding and says something about it. Don't hesitate and get it if you are thinking about it! Sonic with the hookup on them as well!

I bought this amp from Sonic Electronix, I have it pushing four 5x8 infinity kappa speakers in my new 2010 ford explorer sport trac, the birth certificate that comes with the amp says maximum RMS is 676 let me say none of my friends want any part of me when it comes to loud and clean music, the thing is the volume on the amp is half this amp is TRULY MAD. You will not be disappointed, MAD Awesome amp.

Best highs/mids amp i've ever owned. Nice clean looking 4 channel amp.. pick it up.

I have the 2011 650.4 and it is a nice, clean four channel amp. The birthsheet that came with mine said 685watts. So I'm actually pushing my speakers with a little more than 120 at 4ohm. It's a very powerful amp though so make sure you have speakers than can handle the raw continuous power. The THD rating is below 1% and the signal to noise ratio is high making this amp not only powerful but stable and clean sounding. Kicker has done good for the 2011 series of amps. The past couple years they have released some crappy amps, but they've re-designed everything about them and they are awesome.