4-channel car amplifier with built-in programmable DSP — 100 watts RMS x 4

Save 50% on a select amp wiring kit with any $249+ car amplifier with any $249+ car amplifier
  • Brax NOX4BDSP


  • Brax NOX4BDSP

  • Brax NOX4BDSP

  • Brax NOX4BDSP

Crutchfield OMC logo
We don't check this item for fit or compatibility.

Our take on the Brax NOX4BDSP

by Buck Pomerantz

My system has plenty of power. Who needs an amp?

You might think you don't need an amp because you have a 400-watt system in your car, or because your new stereo puts out 50 watts a channel. But those are peak wattage ratings, which may boil down to 15 or 20 watts per channel, using the more realistic RMS rating. An amp sends your speakers the power they need to deliver your music with clarity and impact, whether you're using factory speakers or high-performance components. And low-frequency reproduction requires lots of power, so an amp is an absolute must if you're adding a sub to your system.

Luxury sound that's programmable

If you want the best possible car audio system with total control over sound quality, then Brax's NOX4BDSP 4-channel amplifier should be powering your music. This gorgeous, hand-crafted amplifier features a sophisticated built-in digital signal processor, bringing an unprecedented level of high-fidelity amplification and sound processing into the mobile environment. The NOX4BDSP sends 100 watts RMS to each of your front and rear speakers. Bridged for 2-channel operation, the NOX4BDSP puts out up to 340 watts RMS each to a couple of subwoofers.

Read more

Build-quality that's off the charts

The massive heatsink tells you right away that this is a serious amp. Inside, the multi-layered circuit board is laid out in short, dedicated signal paths to deliver only the purest signal in the fastest time. Brax uses silver solder to secure each discretely mounted component for the best conductivity possible between them. Gold-plated connections eliminate corrosion to keep the signal flowing freely in or out of this amplifier.

Digital signal processor controls it all

You can tweak the sound to perfection with the built-in digital sound processor. After downloading the application and software from Brax, you'll plug your PC or laptop into the NOX4BDSP's USB port. A detailed control panel will appear on your computer screen that lets you set virtually every tunable audio parameter to achieve the highest musical fidelity possible in your car. The visual display shows the resulting sound curve of each setting, so you'll know for sure how your adjustments are affecting audio output. After saving your settings, you can unplug your computer and enjoy the results.

NOX4BDSP tuning screen

The main control panel for the digital processor, as it appears on your computer's screen

Switcher, EQ, time alignment, and more

The built-in processor accepts up to six inputs, which you can assign to the four amp channels and two auxiliary outputs, perfect if you're running separate tweeters, woofers, and subs. A 30-band graphic equalizer on each channel gives you incredible control over the sound. The time alignment feature lets you correct for each speaker's placement in your car, so the sound from each speaker arrives at your listening position at the same time.

An insane filter section

You can configure almost any type of high-pass and low-pass filter on each channel. Not only can you adjust a crossover's frequency, but you can also choose the slope, its "filter characteristics" (see bullets), and adjust its "Q-factor," which adds a bump at the crossover point for certain settings. Filters and EQ can be set separately for each channel, or channels can be linked together for common settings.

Other features

Two separate power supplies ensure stability and dependability. The output power transistors have been hand-selected and measured to match each other so your music will sound consistent and strong. You'll want to display this amp proudly in your system. Hand made in Germany, each NOX4BDSP amplifier comes with its serial number custom milled into the top nameplate.


  • 4-channel car amplifier with built-in 6-channel digital signal processor
  • 24-karat gold-plated RCA input, power, and speaker connections
  • double-sided circuit boards with silver-soldered components
4-channel amplifier
  • 100 watts RMS x 4 at 4 ohms (170 watts RMS x 4 at 2 ohms)
  • 340 watts RMS x 2 bridged at 4 ohms
  • Class AB amp technology
  • hand-selected and matched transistors
6-channel digital signal processor (DSP)
  • DSP settings and adjustments made via laptop or PC through USB port
  • download DSP PC-Tool Software from audiotec-fischer.com or helixhifi.com
  • 6 assignable inputs with 2 auxiliary outputs
  • channel settings can be separate or linked together
  • time alignment in 7 mm increments
  • 30-band graphic EQ on every channel
  • adjustable high- and low-pass filters (20-20K Hz) with selectable slopes (6, 12, 18, 24, 30 dB/octave)
  • selectable filter characteristics
    • Butterworth: sharp transition, suitable for most applications
    • Bessel: gradual transition, suitable for smooth speakers, but not subs
    • Linkwitz: recommended for high-end speakers only, not subs
    • Chebyshev: very sharp transition, useful as high-pass for tweeters or low-pass for subs
    • Self-Define: selectable Q-Factor, 12 dB/octave slope only
  • phase adjustment: switchable 0/180 degrees on front and rear channels, adjustable 0 to 360 degrees on sub channels in 22.5-degree increments
  • 2- or 1/0-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • fuse rating: 100A x 1
  • 12-5/8"W x 2-1/4"H x 12-5/8"D
  • warranty: 2 years
  • Our 60-day money-back guarantee
Be the first to review this product
Great Gear Giveaway rewards card

Submit a review and then enter to win a $500 rewards card

Review this product:

Thanks for taking the time to share your experiences about this product. Please be sure to focus your comments on the product itself. Read our Review Guidelines for more information.

Your email won't be visible. Please use the email address that is associated with your order.
(e.g., JohnD) Your review will be signed using the display name and location
(e.g., Charlottesville, VA)

Click on a star to rate the overall product on a scale of 1-5
1500 characters left
Attach a YouTube Review
Crutchfield Video Review Guidelines
  • Only submit videos that you made or are authorized to use.
  • Do not submit videos that contain music, video or visuals that are copyrighted and belong to someone else.
  • Please see our Review Guidelines for more information.
500 characters left
500 characters left

Add accessories for the Brax NOX4BDSP

You'll need an amp wiring kit to install your new amplifier, as wiring is not included. See all categories & accessories

T-Spec 0PK Installation Kit 1/0-gauge amplifier wiring kit — includes speaker wire
1 person says
Your Price: $189.99
Add to Cart
Rockford Fosgate RFK1 1/0-gauge amplifier power wiring kit
Your Price: $254.99
Add to Cart
T-Spec 16-gauge Speaker Wire Black/white jacket — priced per foot
13 people say
Your Price: $0.69
Add to Cart
T-Spec 12-gauge Speaker Wire Black/white jacket — priced per foot
29 people say
Your Price: $1.99
Add to Cart
Stinger PRO Series 16-gauge Speaker Wire Black jacket — priced per foot
49 people say
Your Price: $0.39
Add to Cart
T-Spec 2-Channel RCA Patch Cables Available in 7 different lengths (20-foot)
25 people say
Your Price: $20.99
Add to Cart
54 people say
Your Price: $9.99
Add to Cart
T-SPEC V12-ANL Fuse Holder 1/0-gauge ANL fuse holder
1 person says
Your Price: $19.99
Add to Cart
T-Spec Capacitor 1.5-farad capacitor with red LCD meter
11 people say
Your Price: $79.99
Add to Cart
Bojo Trim Panel Tools Set of 6 pry tools — helps remove interior and exterior trim and door panels
52 people say
Your Price: $24.99
Add to Cart
Pro.Fit Wire Worm Installation tool helps route wiring through tight spaces
31 people say
Your Price: $12.99
Add to Cart
Metra Crimp Tool and Connectors Package contains crimp tool and over 150 pieces
15 people say
Your Price: $19.99
Add to Cart
S&G Wire Cutter/Stripper Tool Cuts and strips 12- to 22-gauge wire
15 people say
Your Price: $19.99
Add to Cart
S&G Tool Aid 87650 Door Trim and Panel Removal Tool
67 people say
Your Price: $9.99
Add to Cart
Skewdriver Pro SPK4042 Ratcheting straight and offset screwdriver set with 40 bits (Skewdriver Pro with ratchet handle, pictured)
8 people say
Your Price: $49.99
Add to Cart
Bojo Trim Panel Tools Set of 6 pry tools — helps remove interior and exterior trim and door panels
2 people say
Your Price: $29.99
Add to Cart
DEI Heat Shrink Tubing Black 4-foot length (Assortment)
6 people say
Your Price: $24.99
Add to Cart

Why choose SquareTrade?

The #1-Rated Protection Plan

Thousands of people have reviewed SquareTrade Protection Plans — and made us #1.

5-Day Service Guarantee & Free Shipping

We'll repair or replace your item in five business days or less after we've received it, or your plan is free. And, as always, we pay for all shipping.

Protection from Normal, Everyday Use

Repairing your average mechanical or electrical failure can cost as much as buying a new device. With SquareTrade, you're covered — including parts and labor.

3 Year Protection Plan
3 Year Protection Plan
Your Price: $329.99
Add to Cart
4 Year Protection Plan
4 Year Protection Plan
Your Price: $449.99
Add to Cart

For a more in-depth review and enhanced detailed information on the Brax NOX4BDSP, please visit the Crutchfield website product page (/ISEO-rccbcspd/p_875NOX4BDS/Brax-NOX4BDSP.html ).