Kicker IX500.4 Amplifier Review

We’ve all heard the old adage, “good things come in small packages.” Well, the folks at Kicker took it to heart when developing its new top-of-the-line IX series of amplifiers. Designed from the outset to be the best-sounding, best-performing amplifiers Kicker makes, the IX series represents a serious leap forward in technology and, more importantly, sound quality.
In this review, I focus on the four-channel model – the IX500.4 – though it shares its attributes with all of the other amps in the IX series. On the technology side, you have a very compact, ultra-efficient full-range class D design, which means minimal power loss to heat and more power to your speakers (for every watt consumed by your electrical system). But, this is more than just another small amplifier. To understand what makes the IX series special, read on.

The Kicker IX500.4 amp features one of the smallest chassis ever developed by Kicker’s engineers. Measuring approximately 11.4 x 7.9 x 2.2 inches, this amplifier is small enough to fit virtually anywhere as pair of shoes can, which is a bit surprising considering its 125 W x 4 @ 2 O power rating (75 W x 4 @ 4 O). In typical Kicker fashion, the rated power is conservative. Every IX series amp comes with a “Certified Power” performance certificate. According to this, the IX500.4 I’m reviewing here pumps out a total of 556 watts.Kicker IX500.4 Amplifier ReviewBecause these amplifiers are so efficient, they can be installed in a “stacked” configuration (special IXSM mounting brackets are available for stacking IX amps of differing chassis sizes). Fail-safe Integration Technology (FIT) is another class-leading feature on the IX series. FIT provides the ability to connect to any head unit – whether it has RCA outputs or high power speaker level outputs – and integrate into virtually any type of vehicle. FIT also includes a properly-engineered input section with isolated, fully differential inputs that rejects most radiated interference and minimizes all types of noise. There is even a button to enable all four channels to be driven with a single stereo pair of inputs.
If you’ve had problems installing an aftermarket amp in a car that does not provide a turn on lead, you’ll be happy to know the IX series of amplifiers can be turned on via three different methods. First, there’s the traditional 12-volt turn-on connection. Or, if you have a typical source unit with a few volts of DC offset on its speaker outputs, the IX4 can be set to DC signal sensing and will turn on as soon as the radio output comes alive. Finally, if you have a more difficult source with neither of the above methods, the IX500.4 can be turned on simply by sensing the audio signal coming in to the inputs. So, regardless of the head unit you are working with, the IX series has you covered when it comes to turning on.
Other convenient features include: having all wiring connections on one side of the amp, and all the controls on the other. And, when it comes to controls and adjustments, the IX500.4 has pretty much everything you’d expect, with all pass, high pass and low pass 12 dB crossovers adjustable from 50-200 Hz, as well as independently-adjustable bass boost controls for the front and rear channels.
Inside, the amplifier has a very clean layout with plenty of copper trace area on the double-sided fiberglass epoxy PCB. Surface mount parts are used extensively throughout the amp. Output devices are sandwiched between the PCB and the inner top side of the heatsink for maximum heat dissipation. Four 3,300 µF capacitors feed energy to the power supply’s primary stage while a total of eight 2,200 µF caps store energy for the output stage. The input stage uses high performance, low noise and low distortion op-amps. It’s details like these that provide the IX series amps with exceptional sonic performance.

Kicker IX500.4 Amplifier Review

I hooked up the IX500.4 amplifier in my carefully tuned and controlled listening environment with the rear channels bridged to a 12-inch subwoofer and front channels driving my reference bookshelf speakers. I knew Kicker would turn out a decent product, but frankly I was prepared for just another full-range class D amp that was more about small size and power efficiency than sound quality. I couldn’t have been more wrong.
The sound quality of this amplifier is, in a word, superb. It has amazing transparency with virtually no coloration of the original signal. Bass is full, detailed and accurate as is the middle and upper registers. I found myself lost in the subtleties of the music, as I do when listening to a very good home system. You hear the singer’s breath control, drummer’s ghost licks, background singers in detail and (I’ve said so many times in these pages, if you have never had the pleasure of listening to a truly great audio system, you don’t know what you’re missing.) the experience can leave you quite gobsmacked, as I was by the IX500.4.
While the IX500.4 may not be a totally perfect amplifier, to my ears it is certainly in the upper echelon of car audio amplifiers when it comes to sonics. This thing sings and makes you forget it’s even there. To me, there isn’t much higher praise than that.

Kicker IX500.4 Amplifier Review

On the test bench, the measured specs from the IX500.4 amp support the high praise my ears have given it. With only 0.015% THD at one watt, distortion is well below average for a class AB amp let alone a class D product. The frequency response is flat as well, from below 10 Hz to well over 20 kHz. As advertised, the amp makes more power than it’s rated for, with my measurement coming out at exactly 556 watts total – the same as the certification document stated – with signal to noise, crosstalk and common mode rejection ratio figures also well above the industry average.

The Kicker IX500.4 amplifier is a serious piece of quality audio gear made by folks that understand the automotive environment and design products to work in it without cutting corners or creating compromises. The amp can interface with virtually any vehicle, takes up very little room for the power it delivers, and runs cool. The noise rejection of the front end of the amp should go a long way in reducing unwanted engine noise complaints. For me, the purity of the sound the IX500.4 provides is really what make it worth every penny of its $449 price tag.

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