Best Under-Seat Subwoofers for 2021+ Ram 1500 & TRX

If you drive a 2021 or newer Ram 1500 — or the supercharged 702-horsepower Ram 1500 TRX — you already know the factory audio runs out of low end fast. The best under-seat subwoofer for the 2021+ Ram 1500 is the DS18 RAMBASS down-firing loaded package, a vehicle-specific system that tucks two 10-inch shallow subwoofers, a 1500-watt monoblock amplifier, and a full wiring kit under the rear seat with zero loss of bed or cargo space. In this guide we compare it against four more DS18 bass kits, break down real specs, and walk through how to wire a subwoofer into a Ram 1500 without killing your factory Harman Kardon or Active Noise Cancellation system.

Why add a subwoofer to a 2021+ Ram 1500 or TRX?

A subwoofer is the single biggest audio upgrade for a 2021+ Ram 1500 because every factory option is short on deep bass. The 5th-generation Ram 1500 (DT body, 2019 and up) ships in three audio tiers: a base 6-speaker system with no real low end, an optional Alpine system with around 10 speakers and a small under-rear-seat sub, and the premium Harman Kardon 19-speaker setup with a roughly 900-watt amp. Even the Harman Kardon system is widely reported to run out of headroom near the top of the volume dial, which is why so many owners add a dedicated sub.

In a truck, the under-seat location is the smart move. A down-firing under-seat enclosure like the DS18 RAMBASS keeps your bed and cargo area completely free, preserves rear-seat function, and stays hidden for a factory-clean look. That matters on a work truck or a TRX you actually drive off-road. Compare that to a ported box in the back seat or bed, which trades cabin or cargo space for maximum output. At NLP Performance in Tampa, FL, the under-seat RAMBASS package is the kit we recommend most for daily-driven Ram 1500 trucks that need real low end without sacrificing utility.

Best under-seat subwoofer for the Ram 1500 & TRX: DS18 RAMBASS

The DS18 RAMBASS down-firing loaded package is a complete, vehicle-specific bass system for the 2021+ Ram 1500 and the Ram 1500 TRX (2021–2024). Instead of buying a sub, an amp, an enclosure, and a wiring kit separately, you get all of it engineered to fit under the rear seat: two 10-inch shallow-mount subwoofers (600 watts RMS combined, 1200 watts max), the DS18 ZR1500.1D 1500-watt monoblock amplifier, a 4-gauge OFC amp wiring kit, and a Dream LED lighting module wrapped in a black-leather-look down-firing enclosure. DS18 lists the same 21-up box for the Ram 2500 and 3500, so heavy-duty owners can run it too.

How the Ram 1500 bass kits compare

Not every Ram 1500 owner needs the full RAMBASS package. If you want big bass on a budget, a universal under-seat box or a cargo-area enclosure can deliver. Here is how the DS18 options stack up — the RAMBASS is the only vehicle-specific, amp-included kit, while the rest are universal enclosures you can adapt to almost any truck.

Universal under-seat & cargo-area options

If the RAMBASS package is more system than you need, these three DS18 enclosures cover the budget-to-big-bass range. All are universal-fit, so they work in a Ram 1500 and most other trucks — just confirm your under-seat or cargo clearance before ordering.

DS18 4 x 8in Forward-Firing Under-Seat Ported Box

This forward-firing under-seat box runs four 8-inch subwoofers in a ported, spray-liner-finished enclosure. Four 8s move a surprising amount of air for a low-profile box, making it a strong universal pick when you want under-seat bass in a Ram 1500 but do not need the vehicle-specific RAMBASS harness. Pair it with the DS18 ZR1500.1D amp below for the cleanest result.

DS18 Single 12in Shallow Powered Enclosure

The simplest way to add bass: a single 12in shallow sub in a sealed enclosure with the amplifier built in. At 350 watts RMS it will not rattle your mirrors like the RAMBASS, but its sealed design delivers tight, accurate low end and it is the most affordable kit in this guide at $264.62. Because the amp is integrated, you only run power, ground, remote, and a signal wire — ideal for a first-time installer.

DS18 Dual 12in GEN-X212LD Ported Enclosure

When you want the loudest setup, the GEN-X212LD is a loaded ported box with two 12-inch GEN-X124D subwoofers (each rated 450 watts RMS / 900 watts max, dual 4-ohm voice coils) for 900 watts RMS combined, tuned to 35 Hz for deep, aggressive output. It is too large for under the seat, so plan to mount it behind the rear seat or in the bed. Add a monoblock amp such as the DS18 ZR1500.1D and you have a hard-hitting Ram 1500 system for the price of a name-brand single sub.

The amp and wiring that power it

A subwoofer is only as good as the amplifier and wiring behind it. The RAMBASS package already includes the DS18 ZR1500.1D amp and a 4-gauge wiring kit, but if you choose the 4x8 under-seat box or the dual-12 ported enclosure you will need to add them. Here is the amp and the supporting hardware we recommend for a Ram 1500 sub install.

DS18 ZR1500.1D Class D Monoblock Amplifier

This is the same monoblock that ships inside the RAMBASS package: a 1-channel Class D amp rated 1500 watts RMS at 1 ohm (950 at 2 ohm, 550 at 4 ohm), stable from 1 to 4 ohms with a remote bass knob, variable low-pass filter, and 0–12 dB bass boost. It has the headroom to drive any enclosure in this guide. For a clean install, run it on the proper wiring — which brings us to the two pieces of hardware no Ram 1500 sub install should skip.

A note on wire gauge: a 1500-watt amplifier can draw 150 to 200-plus amps, and 4-gauge wiring sits at the low end for that load. If you run the ZR1500.1D hard, step up to 0-gauge (1/0 AWG) power and ground, and do the “Big 3” upgrade — heavier alternator-to-battery, battery-to-chassis, and chassis-to-engine cables — so your lights do not dim on every bass hit. The factory Ram alternator (roughly 80–220A depending on package) and a capacitor will handle the rest for most street setups.

How to install a subwoofer in a Ram 1500

Installing a subwoofer in a 2021+ Ram 1500 takes a few hours for a confident DIYer, and a shop can knock it out in an afternoon. The under-seat RAMBASS box drops into the factory location once you remove the rear under-seat storage tray, so there is no fabrication. The work that takes time is electrical, not mechanical.

Because the Ram retains its factory head unit, you need a clean signal to feed the amp. The most common method is a line-output converter (LOC) that taps the factory speaker wires; a factory-integration interface is the tidier option. The important gotcha: trucks with the premium Harman Kardon system use Active Noise Cancellation, so you should tap the signal ahead of the ANC processing — pulling it from behind the radio — or the system can fight your new bass. Run your power wire from the battery through the firewall with an in-line fuse within 18 inches of the positive terminal, ground the amp to clean bare metal, and route the remote turn-on lead. Crew Cab trucks have the easiest under-seat access; Quad Cab owners should confirm clearance, and Alpine-equipped trucks have a small factory sub under the right rear seat that comes out first.