The Rockford Fosgate PS-8 is the under-seat powered subwoofer from the same Punch series as the Rockford Fosgate P300 (my pick for the best powered subwoofer overall). As with other under-seat subs, the woofer is 8-inches. However, it has a 150-watt amplifier.
At around $175, the PS-8 is only $25 cheaper than the P300, a far better performing and powerful subwoofer. That said, the difference in size might be worth the price difference, as the PS-8 fits under your car seat while the P300 likely only fits in your trunk or storage area.
The biggest issue with the Rockford Fosgate PS-8 is the performance. It was the worst performing bass in my tests. The sweet spot of this sub isn't terrible, but it's below the 50-percent point on the volume. Pushing the volume beyond this point causes the performance to suffer significantly. Within the context of a mix, the sweet spot was barely noticeable as a subwoofer. When I turned it up, the distortion and clipping of the woofer became noticeable. It has a sealed enclosure designed for a tight and accurate performance, but it sounded a bit too growly at higher levels.
The size of the bass earned a B grade. It's not bad for an under-seat subwoofer, but not great either. With a 150-watt amplifier, it was certainly capable of reaching the teeth rattling levels of the larger 12-inch subs I tested, but at this level the bass performance was too poor to provide a good listening experience. It matters little how big a bass is if the performance suffers.
The controls received a B grade for ease of use. It has six controls and includes a wired remote to adjust volume levels from the driver's seat. However, the knobs are flat, making them difficult to adjust with fingers. In addition, the control panel is on the short side of the rectangular subwoofer, making it difficult to access once it's under your seat.
As an under-seat car subwoofer, it has a slim design. However, the height is bigger than other under-seat subs by about a quarter inch. While this won't make any difference in some vehicles, it won't fit in as many vehicles. For example, it doesn't fit under my car's seat, but the other under-seat subwoofers do. This is definitely a consideration if your car's seats have less than a 3.25-inch clearance.
The Rockford Fosgate PS-8 features a 150-watt amplifier driving an 8-inch woofer. It's fairly big for an under-seat subwoofer, so make sure you make sure your seats have a 3.5-inch clearance. The performance isn't terrible, but it isn't great either. There are better car subwoofers.