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Alpine PSU-300FRN

Powered System Upgrade for select 2010-up Toyota 4Runner without factory premium sound

Item # 500PSU3FRN

The top two complaints about the way a car's factory system sounds are that there's not enough volume and...

Find what Fits your vehicle

The top two complaints about the way a car's factory system sounds are that there's not enough volume and...

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Discontinued item
5 questions - 5 answers

Item # 500PSU3FRN

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Installation help for your car, from our experts.

About the Alpine PSU-300FRN

Fix your factory sound

The top two complaints about the way a car's factory system sounds are that there's not enough volume and there's not enough bass. Alpine's PSU-300FRN Powered System Upgrade solves both of these issues in your Toyota 4Runner with a neat and clever combination of products designed to bring joy to all music lovers.

Fix your factory sound

The top two complaints about the way a car's factory system sounds are that there's not enough volume and there's not enough bass. Alpine's PSU-300FRN Powered System Upgrade solves both of these issues in your Toyota 4Runner with a neat and clever combination of products designed to bring joy to all music lovers.

The components

The package includes a compact 4-channel amplifier and a powered subwoofer, both mounted in a Toyota-specific bracket which mounts under the front passenger seat and wires up using Toyota-specific harnesses. The PSU-300FRN upgrade is compatible with the factory Toyota base radio and almost all other aftermarket receivers. Alpine says you should be able to install this upgrade in your car in two hours or less.

Universal power pack

Alpine's KTP-445U Power Pack amplifier increases your radio's power output to 45 watts RMS by 4 channels, considerably more than what's put out by the Toyota radio. A universal plug lets you feed a signal via RCA outputs or speaker-level wiring. A built-in high-pass filter optimizes the sound for your speakers.

Compact powered subwoofer

Alpine's PWE-S8 powered sub uses a Class D amplifier rated at 120 watts RMS to drive the 8" shallow-mount, high-excursion subwoofer, so there's plenty of power for your bass. The amp features controls for phase, gain, and a low-pass crossover, so you'll be able to blend the bass with the rest of your system.  A wired remote control lets you adjust the bass level from the driver's seat. 

Important Note: This upgrade package won't work with Toyotas with the factory premium JBL system.


Product highlights:

  • factory audio system upgrade
  • fits select 2010-up Toyota 4Runner without factory premium sound
  • Alpine KTP-445U Power Pack 4-channel amplifier
    • 45 watts RMS x 4 at 2 or 4 ohms
  • Alpine PWE-S8 compact powered subwoofer
    • 8" woofer
    • 120 watts RMS amplifier
  • vehicle-specific bracket holds sub and amp under front passenger seat
  • vehicle-specific wiring pre-cut and terminated
  • warranty: 3 years
  • Our 60-day money-back guarantee
  • MFR # PSU-300FRN

What's in the box:

  • PWE-S8 Powered subwoofer w/ attached mounting bracket
  • KTP-445U Power Pack (pre-attached to subwoofer mounting bracket)
  • 7' Main harness w/ inline 15A ATC fuse
  • 12' Loomed 10 ga. power cable (inline 20A ATC fuse)
  • 10" T-harness
  • Three 10" RCA adapters (front / rear / sub)
  • Remote bass-level control (attached 16' cord)
  • 2" Patch of hook-and-loop fastener
  • Ten 6" wire-ties
  • One 1/2" self-tapping screw
  • 1 Lock-washer
  • Instruction manual
  • Warranty information
  • Alpine technical support information

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More details on the Alpine PSU-300FRN

Pat M.

Product Research


Overview: Alpine's PSU-3FRN is a dedicated 300 watt sound system designed specifically for 2010-2019 Toyota 4Runner models not equipped with a factory amplified sound system. The system includes a KTP-445U 4 x 45 watt amplifier, a PWE-S8 8" powered subwoofer, and all the wiring needed, pre-loomed and ready to install. The PSU-3TND also includes a remote bass knob for changing the bass level from the dash.

Wiring: The PSU-3FRN system can be interfaced with a factory radio (non-amplified) or an aftermarket radio. The included T-harness interfaces the factory wiring in the dash, providing either a speaker-level signal from a factory radio or an RCA line-level signal from an aftermarket radio, to feed to the Alpine KTP-445U amplifier. The T-harness also feeds the amplified return signal back into the factory wiring and out to each of the speakers, utilizing the factory speaker wires. The provided wiring includes a loomed 10 ga. power wire, with inline fuse holder, that gets run to the battery, providing power for both the 4-channel amp and the PWE-S8 subwoofer.

Note: The Alpine PSU-3FRN upgrade kit is not compatible with a factory amplified sound system.

Mounting: Alpine provides pre-attached brackets that are designed specifically to mount both the KTP-445U amp and the PWE-S8 subwoofer underneath the passenger front seat. This means no usable space in the vehicle is taken up by the sound system.

KTP-445U: The Alpine KTP-445U Head Unit Power Pack is a power upgrade amplifier that allows you to add higher output and more dynamic response to your aftermarket or factory installed car stereo system (without factory amplifiers). The Power Pack employs a 45 watt x 4 channel amplifier with an unbelievably low noise floor, taking extra care to ensure a clean signal path, with no extraneous interference. The end result is a 1 Watt Signal-to-Noise Ratio of 82dB or better. Uniquely, the amplifier distortion actually decreases at higher frequencies, resulting in a clean and clear signal where your ear is most sensitive to distortion (< 0.03% THD+N @ 1W; 1% THD+N @ rated power). The Alpine KTP-445U Head Unit Power Pack provides independent controls for the Front & Rear inputs.

  • Front & Rear Gains: The Power Pack provides simple variable gain controls (speaker level: 0.5-10V, low-level: 0.2-4V) for flexibility and a wide variety of system applications.
  • Front & Rear HPF: High-Pass selectable switches for the amplifier's Front & Rear inputs allow frequency filtering for a wide variety of speakers. Choose "Full-Range" or a selectable range (60Hz, 80Hz, 120Hz) to fine-tune your crossover points (-12dB/oct.).
  • Configurable Inputs: On the bottom panel of the Power Pack there are selectable input options to accommodate Speaker-Level (0.5V-10V) or RCA (0.2V-4V) inputs.
  • 4Ch/2Ch Modes: Selectable 2-Channel & 4-Channel options give you the control to determine source inputs, and can eliminate the need for Y-adapters.

PWE-S8: The Alpine PWE-S8 is a compact self-amplified subwoofer with pre-installed brackets that allow it to fit underneath the passenger's front seat, keeping it out of sight. The PWE-S8 includes a built-in 120 watt Class D amp along with an 8" high-excursion subwoofer. It can accept either line- or speaker-level inputs and features an Auto Turn-on circuit that will activate the amp when it senses a signal on the speaker-level inputs. An included wired remote lets you easily adjust the bass level from the front seating area. The control can be mounted under a dash panel and gives you a level range from 0 to -20 dB, relative to the gain setting on the amplifier. Controls on the subwoofer include:

  • Gain: Can vary the input level from 0.2 - 4.0 volts line-level and 0.5 - 10 volts speaker-level.
  • Low Pass Filter: Rotary control that can set the filter cutoff between 50 - 150 Hz.
  • Phase: Switches between 0˚ and 180˚.
  • Power Mode: Switches between SP IN (speaker-level input) and REM (wired remote input).

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Customer Q&A

5 questions already asked

The description states 45 watts by 4 but I believe there a 6 speakers in the 4 runner . front doors, passenger doors and rear hatch. Does this unit only send power to the front and passenger door speakers?
[ Nicholas  Oct 24, 2021 ]
1 answer
No, as the speakers are wired in both series and parallel. The rear hatch and rear door. If im not mistaken the dash speaker are ran in parallel with the front door speakers making the source unit see two speakers and the rear doors and the hatch are either ran in parallel or series to where the source unit sees two speakers. I'll be honest and was displeased with the sound staging of the Alpine and returned it. I did a full on custom system and absolutely love it.
[ JEFFERY JOSEPH  Oct 26, 2021 ]
Will this work in conjunction with the Alpine Halo9?
[ KURT  Jul 31, 2020 ]
1 answer
That PSU-300FRN is intended to be used with a factory system. You could cut the pre-terminated connections off and use it with the Halo-9 but it would probably be more efficient to simply buy those parts separately. You can connect with one of our friendly product advisors to put together a cart with everything you would need here:
[ Cosmo  Aug 16, 2020 ]  Staff
Do you have to run wires to the existing speakers? Is all other power provided to the speakers as long as you hook everything up through the dash?
[ Michael  Sep 22, 2019 ]
1 answer
You do not have to run wires to the existing speakers. The provided harness interfaces directly with the head unit. Power is provided to both the speaker amplifier and subwoofer via the power cable you run through the passenger side firewall. The power cable connects to the wire harness under the passenger front seat at the subwoofer and amplifier.
[ Nicholas  Oct 02, 2019 ]
Are there any other mods that need to occur? I see that it mounts under the front passenger seat, but are the wires easily accessible or do you need to remove the entire dash and run additional wire to the sub/amplifier?
[ Kristoffer  Jul 04, 2019 ]
2 answers
You will need to remove the HVAC, radio, 4WD shifter, shifter panel (Don't completely remove or you will damage the 4WD shifter boot.), lower trim panel, passenger side under dash cover, passenger side door will, passenger side kick panel, and passenger front seat. The supplied directions are clear and will walk you through this process. Take you time when running the harness from the center console to the passenger seat floor. Utilize the notch in the console and slit in the carpet floor under the seat for a cleaner installation. The only instruction that wasn't clear was wear to drill the negative group terminal. Make sure you do this correctly or the unit will not turn on. I chose to drill near the seat mount closest to the passenger front door. The negative ground terminal can be concealed with the plastic seat screw covers.
[ Nicholas  Oct 02, 2019 ]
You will need to access the sub dash area, and their are instructions that tell you how. You will be running wires, but it comes with the harnesses that plug into your factory wiring. According to Alpine, this is approximately a 2ish hour job.
[ Calvin  Jul 12, 2019 ]  Staff

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