Many car audio enthusiasts and installers are intimidated by the variables involved in designing a truly good performing subwoofer system for a car. And truth be told, it does take a good deal of experience, knowledge, and technical ability. Or, you can leave all that to the pros, and simply by a plug and play subwoofer system, where all the guesswork has been done for you. And that’s precisely what the folks at Rockford Fosgate have done with their PS300-12 “Punch Overload” Powered Subwoofer System. I recently had a chance to test one of these solution driven products in the lab, and I came away quite impressed.
Design and Features
The Rockford Fosgate Punch Overload PS300-12 is a thoughtfully designed product, obviously from the minds of engineers who have some experience with automotive subwoofer systems. The product can be mounted in a variety of positions, and it’s designed to be easy to remove as well, with quick disconnect type connections for power and signal. And if you have ever had a woofer accidentally damaged because you were too cheap to buy a grille for it, you’ll be happy to learn that the PS300-12 woofer is always protected from errant golf clubs, ski poles or hockey sticks by a “loading plate” that covers the entire woofer, and lets the sound exit around the enclosures perimeter. The self powered subwoofer system consists of a nice looking, and fairly small rectangular shaped enclosure, measuring 15-1/4” x 11-1/4” x 22-3/8”, and houses a special 2 ohm 12-inch Punch woofer and amplifier. The Rockford logos are designed into the top plate and bottom panel, making one or the other visible regardless of how you mount it. The system comes with all the brackets and hardware you need to get it securely fastened down, which is critical for safety.
The Punch amplifier is integrated into the end panel, and even its connections and controls have been simplified. There is a single plug for the power, ground, and remote trigger, then a pair of RCA’s or high level signal Molex inputs, an optional remote level control, and a gain knob. And that’s it. All of the crossover filter and subsonic filter settings are preset for you.
Of course the first thing I did when I unpacked the Overload system was take it apart. By unscrewing four large capscrews, I removed the top “loading plate” that is used in lieu of a grille, and then I removed the woofer. The enclosure itself has an internal volume of just over 1 cubic foot, and is manufactured from a material called “acrylonitrile butadiene styrene” or more commonly known as ABS. The interior of the enclosure is ribbed for both structural integrity as well as resonance reduction. To further reduce the possibility of cabinet resonances, the interior panels of the enclosure are covered with a high mass mat-type material that prevents resonances. On the “floor” of the enclosure is a slot type vent, which I tested to find that it “tunes” the air in the enclosure to resonate at 40Hz. The amplifiers mounting area is sealed off from the inside of the enclosure, and the amplifiers heatsink is mounted externally.
The woofer is a design that is proprietary to the Overload system, using fairly non-traditional parts when compared to a typical Punch woofer. The most obvious difference is the 12” driver uses a paper cone and dust cap instead of the more common, (and some would say less natural sounding) poly cones. Because the woofer isn’t really meant to be seen, the cosmetic treatment is fairly limited, which is fine. A stamped steel basket supports the large motor assembly, and the build quality of the woofer is excellent, as one expects from a Rockford Fosgate woofer.
There are other differences from a typical Punch woofer as well, such as the non-vented backplate, and basic push on spade type terminals. But where it counts, the woofer of the PS300-12 system is all business, with a 2.5” voice coil wound on a black anodized aluminum former, a double stacked magnet structure, and tinsel leads that are stitched to the spider for greater reliability.
The amplifier section of the Overload system is rated at 300 watts into 2 ohms. The amp is a Class AB design, and is also a proprietary design specific to this application. As I was later to learn, the frequency response of the amp was designed specifically to work with the supplied woofer, in this specific cabinet. The amp uses a removable power connecting plug that accepts 8ga wire, and the RCA connectors are heavy duty looking panel mount types. Other than a gain control knob, there are no adjustments to be made, but you can purchase the optional PEQ remote control if you like to adjust things as you cruise.
Read on for Results
I connected the Punch Overload into my system, and played a couple dozen of my favorite subwoofer evaluation tracks. I have to say, I was expecting a relatively compromised system, simply because it’s quite small, the enclosure is plastic after all, and maybe I’m just used to having a lot more control and adjustability. But to my surprise, the system actually sounded excellent. The ABS enclosure was dead quiet, and I never heard one rattle or creak. This is actually a very good enclosure, and because it’s made of ABS instead of MDF, its lightweight and is immune to moisture problems. As it turns out, the amount of EQ built into the amplifier and the choice of crossover points, combined with the enclosure tuning, and this natural sounding paper cone woofer, all came together exceptionally well. Fast, detailed bass lines from the late great Jaco Pastorius were reproduced with very good clarity and definition. The system plays quite low too, as Don Dorsey’s pipe organ tracks showed. Of course it does give up a little bit of very low frequency output to a sealed system, but what it loses there it more than makes up for in increased output above about 30Hz. Rock and Rap music really make the Punch Overload system shine, and whether you listen to 50 Cent or Keith Urban, the system works very well. Kick drum notes were natural sounding with the batter strike and the resonance reproduced faithfully. I did occasionally wish for a bit more gain in the amplifier, as it seemed to take a fair bit more signal to drive the PS300-12 than my main amplifier. The system didn’t lack power by any means, it just needed more input signal than normal.
On The Bench
Of course while I had things apart, I took the opportunity to measure the amplifiers performance, and I’m happy to report it exceeded all the published specs. The amp developed 319 watts, and distortion was very low at 0.07%. The signal to noise ratio also measured very good at -92dBA referenced to 2V of output. Efficiency was decent too, with a full power efficiency of just over 67% at full 2 ohm power. The Overload system isn’t likely to overload your charging system as it drew a maximum of 33.0 amperes of current at full power.
As I mentioned previously, the electronics in the amp have been massaged to suit this specific application, which is a benefit you don’t get on an amplifier that may have to drive everything from a pair of 4” coaxes to 15” woofers. The amp has a built-in preset EQ curve, as well as a subsonic filter, and a low pass crossover. Because the engineers knew exactly what woofer and enclosure would be used, they could simply design the right settings into the amp, and save everyone the hassle of trying to figure it out for themselves.
The PS300-12 “Punch Overload” system is a great solution for anyone who wants authentic sub-bass performance but is reluctant to either spend a lot of time and money trying to design something themselves, or if you simply need to add a “real woofer” to an otherwise decent sounding system. While not cheap at $799.99, you know you are going to get a system that works properly and you may end up saving money compared to what it could cost if you have to re-do things to get the performance you’re looking for. It’s a good looking and relatively small system that will fit in almost any application. But the best part of it, as it should be, is the way it sounds. My buddy now understands what his OEM system was missing, but with a Rockford Fosgate PS300-12 Overload system in his trunk, he’s now bumpin’ with the best of them.