2023 Prius Subwoofer Under the Seat: Power, Ground and Remote
A 2023 Prius subwoofer does not have to cost you the cargo floor. In this install we paired a compact powered Kicker Hideaway subwoofer with the Beat-Sonic ENX-T338 Encore X DSP amplifier kit for the 2023-2026 Toyota Prius, tucked the sub under a seat, and kept the factory head unit and speakers exactly where Toyota put them.
Short answer: the ENX-T338 gives your non-JBL Prius a dedicated subwoofer RCA output and a 12V remote lead, so a powered under-seat sub only needs three more things from you: a fused power run to the 12V battery, a solid chassis ground, and clean routing under the trim. No factory wires get cut.
We already covered the DSP side of this car in its own video, so this post stays on the part most people get stuck on: the wiring between the amp, the sub, the battery and the chassis. If you want the bigger picture on where a sub can live in a small car, read our guide to placing a subwoofer without losing trunk space.
Why a 2023 Prius Subwoofer Belongs Under the Seat
The fifth generation Prius has a sleek roofline and a cargo area that fills up fast. A traditional sub box eats a big piece of it. A compact powered sub has its own amplifier built into a slim enclosure, so it fits under a seat and leaves the hatch free for groceries, luggage and gear.
The catch is that a powered sub still needs a signal, a turn-on lead, power and ground. The factory Prius stereo has no subwoofer output to give it. That is the gap the ENX-T338 fills. It plugs in behind the head unit and adds six RCA outputs, including a dedicated subwoofer channel, plus a 12V remote output. You can browse the rest of our plug-and-play options in the amplifier collection.
What the Encore X DSP Adds Before the Sub Goes In
The ENX-T338 is a 4 x 45W Class AB amplifier with a 24-bit DSP. It ships with a tune made for the 2023-2026 Prius, so it sounds right out of the box. If you want to go further, you plug a Windows PC or laptop into the USB port and adjust the 31-band EQ, crossovers and time alignment with our free software.
For a sub install, two parts of the kit matter most:
- Subwoofer RCA outputs. The sub left and sub right RCAs are where the sub's signal comes from.
- Remote output. A 12V remote lead (max 100mA) that tells the sub to wake up when the stereo turns on.
One fitment note before you order. The ENX-T338 is for the Prius without JBL, which means the LE, XLE and Nightshade Edition. The Limited comes standard with JBL and is not compatible.
The Wiring Plan, Step by Step
The customer brought the sub to us and asked for a clean, hidden install. Here is how the team handled each lead.
1. Convert the sub's input to RCA
The sub's input harness came with speaker-level leads. We converted them to RCA so they could plug straight into the ENX-T338 sub outputs. The leads are polarity marked, one with a black stripe and one without, and the colors match, so getting it right takes seconds. We insulated every joint and gave each a tug test. The female-to-female RCA extension felt loose, so we wrapped it in electrical tape to keep it from working apart over bumps.
2. Join the remote wire the same way
The remote lead from the ENX-T338 harness gets joined to the sub's remote input with the same method. When the head unit turns on, the amp sends 12V down this wire and the sub powers up with it. When you turn the car off, the sub goes quiet too.
3. Route the harness under the rear trim
The rear seat side panel pops loose by hand. From there the team fed the harness behind the seat and under the panels, using a hook tool to pull the wires through the openings. A little flossing motion at the end seats the wire fully under the trim so nothing bulges. Every clip went back in flush, because the car has to go home looking like it arrived.
4. Run power to the 12V battery
The power lead is the long one, and it is the only wire that goes to the battery. We routed it along the same trim path, crimped a ring terminal on the end and fastened it to the battery terminal with a 12mm. The inline fuse sits in a spot where it stays accessible but out of the way once the covers go back on. Before buttoning anything up, the team powered the amp and sub to confirm everything worked.
5. Ground to bare chassis
The sub's ground lead had to be extended. We ran it underneath and used a factory 10mm bolt close to the sub, with the ring terminal tucked right behind it and the trim cover hiding the connection. A short ground to clean metal is one of the best ways to keep a sub from humming or cutting out.
6. Mount the remote bass knob
The bass knob lets you turn the low end up or down from the driver's seat. This customer wanted it near the shifter, so that is where it went. Pick a spot you can reach without looking, and route the cable under the console trim.
Common Wiring Mistakes We See
- Grounding to painted metal. Paint is an insulator. Use a factory bolt that bites bare metal, or scrape the contact point.
- Skipping the fuse near the battery. The fuse protects the wire, so it belongs close to the power source, not next to the sub.
- Leaving RCA joints unsecured. A connector that slips half out gives you a sub that cuts in and out. Tape or heat shrink it.
- Running power next to the RCA lead for long stretches. Keep them apart where you can to avoid picking up noise.
- Forcing trim clips. The Prius panels release with steady hand pressure. A plastic trim tool beats a screwdriver every time.
The team was clear in the video that this is one way to do it, not the only way. A powered sub is a simpler, cost effective route, and there are plenty of other setups. If you are weighing amp tuning and sub integration on a Prius with a different amp, our Prius gain setting and sub guide covers the Encore Alpha route.
How It Sounds After the Install
The video ends with a recording made in the car, so you can hear the difference yourself rather than take our word for it. The ENX-T338 handles clarity and staging for the door speakers, and the sub takes the low end those small factory drivers cannot reproduce. Nothing is visible from the seats, and the cargo area is untouched.
If you like the idea of a hidden sub but drive something else, see the same Kicker Hideaway approach in our GR Corolla subwoofer install. Road noise is the other half of the equation in a hybrid, and our sound deadening kits help the new bass come through cleanly at speed.
Keep Everything Factory Up Front
Because the ENX-T338 plugs in behind the head unit, your Toyota screen, steering wheel controls and factory speakers all stay in place. If you later want phone mirroring on the factory display, browse our Toyota CarPlay and Android Auto kits, or check the stereo interface collection for harness and integration parts.
FAQ
Does the ENX-T338 have a subwoofer output for the Prius?
Yes. The ENX-T338 has six RCA outputs, including a dedicated subwoofer channel, plus a 12V remote output to turn a powered sub or external amp on with the stereo.
Will this work in a Prius Limited with JBL?
No. The ENX-T338 is for the 2023-2026 Prius without JBL: LE, XLE and Nightshade Edition. The Limited comes standard with JBL and is not compatible.
Does a powered sub need its own power wire to the battery?
Yes. A powered sub has its own amplifier, so it needs a fused power lead to the 12V battery and a short ground to bare chassis metal, along with the RCA signal and remote lead.
Do I have to replace the factory head unit or speakers?
No. The ENX-T338 is plug-and-play and works with your factory head unit and speakers. It does not permanently modify the factory harness.
Can I tune the sub after it is installed?
Yes. The ENX-T338 comes with a Prius tune preloaded, and you can adjust crossovers, EQ and time alignment with Beat-Sonic PC software over USB on Windows 7 or later. The remote bass knob also lets you change the sub level from the driver's seat.
Want Us to Wire It for You?
If you would rather hand us the keys than pull trim panels, our La Mirada, California shop installs the ENX-T338 and under-seat subs, often same day. Book a Prius audio install with our team and tell us what sub you have in mind.