JBL BassPro SL Underseat Car Subwoofer Review: Top Full Guide 2023

JBL BassPro SL Underseat Car Subwoofer Review 2023

JBL basses are well known in the industry for quality. The BassPro SL is no exception. Continue reading our JBL BassPro SL Underseat Car Subwoofer Review to learn more information. This is a great product for those who are looking for an underseat car subwoofer. It provides crisp, clean bass for all of your favorite songs.


The JBL BassPro SL-powered woofer can be placed under many cars’ front seats and provides powerful bass for any car’s audio system. The BassPro SL has an electronic crossover control and adjustable EQ settings that allow you to tune it to your system, car’s acoustic environment, and your personal listening preferences.

The digital amplifier is an efficient and energy-efficient device that drives the subwoofer while remaining cool even when it’s being driven hard. The BassPro SL produces great bass without taking up too much space.

JBL BassPro SL Review

JBL BassPro SL Underseat Car Subwoofer Review


  • Power 125w RMS
  • Frequency Range 40 Hz-150 Hz
  • Bass Boost 0 to +9dB @ 70 Hz
  • Input Sensitivity: 200 mV to 2V (RCA), 2V to 20V (Spkr Level)

JBL BassPro SL Features

The JBL BassPro SL subwoofer system is entirely self-powered and self-contained. It was specifically designed to fit in tight spaces, such as the space below your seat. The system’s profile height is only 71mm (2.1875 inches), so it will fit under any seat except the lowest.

The system’s length and width are 344 mm (13.65625 inches) & 250 mm (9.875 inches), respectively. This compact package includes a proprietary eight-inch shallow-mount woofer and a Class D amplifier with 125 watts.

The standard features of the BassProSL include an adjustable low pass crossover filter that can be adjusted from 50 to 120Hz and a bass boost control, which can increase output at 70Hz. You can also listen to the BassPro SL in any position you prefer and choose the best one for your application.

The input signal can either be supplied from an OEM system or a traditional RCA signal for ease of installation. A switch allows you to choose between 10,000 or 120 ohms for the desired input impedance. This ensures compatibility with almost all OEM systems. Depending on your vehicle, you can choose between traditional 12-volt turn-on functionality or signal sensing.

A wired remote control can be added to allow level adjustment from the driver’s chair. The connections are simple with standard terminal strip-gold-plated screws for power, ground, and remote wires. Terminals are sufficient to handle the low current demands of the internal amplifier. Therefore, there is no need to use larger power cables than 10 gauge.

The internal amplifier is a Class-D design with a maximum current draw of fewer than 12 amps. It runs cool and drives an eight-inch, low-profile woofer that was designed for the ABS enclosure.

The woofer weighs more than 26 ounces and is robust with a 110-mm ferrite motor assembly. It drives a 38mm (1.5-inch), four-layer copper voice coil wound onto a Til glass fiber forerunner. This assembly moves an ABS and polycarbonate cone anchored by a butyl rubber surrounding.

The ABS enclosure is well braced internally. It also includes many strengthening ribs that prevent unwanted resistance and increase the enclosure’s strength. Additionally, the enclosure has a woofer that is mechanically attached to both ends. This further reduces resonances and enhances stability.

Also read: Best Underseat Subwoofer: Top Brand Reviews 2023

Sound Quality

JBL BassPro SL sound quality

Ok, so I have to admit that my expectations when hooking up the BassPro SL to my reference system for the listening session were very low. This is an eight-inch woofer housed in a small sealed enclosure.

When I start playing music, I am surprised by the output and the quality of the sound. I was expecting a loud, distorted sound due to the limited air space. But I got the tight, precise bass. Although the output drops below 60 Hz quite quickly, it will add an additional dimension to your music if you only have OEM speakers.

I start with well-recorded tracks by Rush, Dire Straits, and Mighty Sam McLain. With its rich, warm sound and unexpected musicality, the JBL system makes me believe in it. I was surprised at the clarity and definition of the woofer’s sound.

I was able to play more bass-heavy music like Yello or Hot Fire, and the woofer could go low enough and loud enough to handle the amp’s power without any complaints. Although you won’t win any SPL contests using it, it should be sufficient for most people who drive an average vehicle.


JBL BassPro SL Underseat Car Subwoofer is a well-priced and powerful product that gives you the best value for money. The sophisticated design and quality of sound will exceed your expectations and will never disappoint. Its astonishingly low level of distortion and the perfect match with the car’s interior will sure be a great addition to your car.

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