With a fresh pair of JL Audio 10TW1-4 subwoofers just waiting to be fired up, I needed to replace the JL XD300 amplifier with something that had a lot more power. I decided to stay with a class-D because it still had to fit under the front seat, and since I didn’t want to run more than one amp cable from the battery to the interior I decided to go multi-channel for future upgrade purposes. I found what I was looking for in the Alpine PDX-V9 5-Channel Amplifier (side note: I had to remove the old amp cable because it was only 8-gauge, and the new amp needed 4-gauge). The amp is conservatively rated on the box at 100-watts x4 + 500-watts x1… but Alpine actually bench tests each PDX amp before packaging and places a “Verification Certificate” inside the box showing the actual output of that particular unit (more on this later.)

New Alpine amplifier mounted under the passenger seat, replacing the Audio Control Epicenter. Very compact but very powerful.
View of the amp how it sits with the passenger seat bolted down. This view is from the front passenger footwell.
View of the amp face and controls. It sits back far enough where it is behind the floor vent, out of harms way.

With the new amp, I had two control knobs for my system – one for the Audio Control Epicenter Processor, and a new knob (Alpine RUX knob) for remote bass level control. After surveying the interior and imagining where I would like to reach the controls, I custom mounted the two knobs (and Epicenter LED indicator) in the lower center console area, to the left of the “4WD” knob. In this position I could easily reach the knobs while driving, and it blended in with the center console “look” because the two black knobs actually brought some symmetry opposite the two OEM 12v black receptacles on the right side of the lower console.

Alpine bass level control knob on top, Epicenter LED and processor level knob underneath.

Speaking of the Epicenter, it got relocated to under the driver’s seat.

My stereo system bass processing happens under my butt, technically.

Oh yeah – about the PDX-V9’s “Verification Certificate” – here it is. The actual output of my particular amp at 14.4v is 138-watts x4 @4-ohms for the main channels + 564-watts x1 @4-ohms for the subwoofers. That meant a significant boost on the low end compared to the old setup, plus now I have 4-channels of high power for the main speakers. The only bad part of this was that  it basically kickstarted a 1 ½ month-long obsession of installing audio-related components every weekend until my audio upgrade project was complete.

Do the math… that’s over 1,000-watts (1,116-watts to be exact, woo hoo!).

So now I had A LOT more bass than I had imagined, and it’s great. Because of the way the subwoofer box vented the sound downward into the angled floorboard and then directly into the cabin (as opposed to not going through back seats like in a car with the sub box in the trunk) let me tell you – it’s really loud. So loud that things started to rattle everywhere – which meant the next step to my audio upgrade was sound dampening.