The T400X4ad is chock full of Rockford Fosgate technology, including a bunch of stuff you simply can’t find on any other brand. As any experienced person will attest, system setup and tuning can make or break an entire install. To make sure the amp gain settings are dialed in correctly, one of the most important features of the T400X4ad (as well as many other Rockford Fosgate amplifiers) is its patented“C.L.E.A.N.” setup system, short for Calibrated Level Eliminates Audible Noise.
The amplifier is equipped with input and output clip indicators to help aid in the setup process for a trouble-free install. Included in the box is a special setup CD. Simply play the appropriate track in your head unit and increase the volume setting until the input clip indicator lights up on the top of the T400X4ad, then reduce the output by one step.
After, simply adjust the gain controls on the amplifier until the multicolor output clip indicators turn blue.
That’s it. You’re done. If you want to tweak it a bit more to dial in some gain overlap and really get it perfect, there are additional tracks on the disc and you can double check your setup by monitoring the amp output clip indicators while playing your favorite music.
Other unique features of the T400X4ad are the “Constant Power” and Class-AD topologies that work together to maximize power output into the speaker load, while maintaining optimal efficiency to minimize amplifier heating.
Space constraints prevent me from going into the details here, but if you’d like to know more about these technologies, there is plenty of information on Rockford Fosgate’s website. And on the subject of keeping heat under control, the T400X4ad also incorporates a special three-stage airflow system with dual fans to keep things cool.
Of course, all the typical features are included as well, with adjustable frequency all-pass, high-pass and low-pass crossovers for both front and rear channels, and Punch. equalization, which unlike a typical bass EQ, provides boost at both the lower and upper sections of the response curve.
After connecting the front channels of the T400X4ad to my reference component speakers and the rear channels bridged to a 12-inch, four ohm woofer, I sit down and begin a serious, but thoroughly enjoyable evaluation of the Rockford’s sonic credentials.
As usual, my musical selections run the gamut from classical and jazz standards on audiophile labels, to well-recorded pop, rock, country and even some hip hop. Over the course of three hours, no matter what I play, the T400X4ad sounds natural, transparent and remarkably good.
The amp performs with sonic excellence, reproducing natural sounding music with good detail, and the stereo image is equally impressive. I’ve been driving the amp fairly hard for quite a while, and I note that it’s quite warm. But it stands to reason that an amp with that much power in such a small heat sink is going to get good and warm – even with forced air fan cooling.
Based on what I experienced, I suggest giving this amp plenty of room to breathe and dissipate heat if you really plan on putting it to work. It’s simply a good practice to follow with any amplifier.
This test report is also available on the PASMAG app. Download it from the App Store.
On The Bench
On the test bench, the Rockford Fosgate amplifier easily surpasses all of its published specifications – and most by a considerable amount. Power is almost 50% greater than advertised, and other typical specifications are equally impressive. I notice some heat buildup during bench testing as well, so giving the amp plenty of breathing room is a good idea when planning your installation.
This is one of the highest power-dense amplifiers I have tested to date. The amount of power developed by the T400X4ad is fantastic, but if you are going to drive it hard on a regular basis, just give it a fighting chance to rid itself of heat. It sounds great, and the special Punch EQ circuitry provides a better balance of sound when you have real world road and wind noise to overcome. It’s very well built and like other Rockford Fosgate products, should be an exceptionally reliable performer.
Amplifier Review BY GARRY SPRINGGAY
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