AMPLIFIERS
JBL BPx500.1
By Paul Sonoda
Posted on Thursday, Apr 8, 2004

Two years ago, JBL unveiled the massive A6000GTI: the world’s most powerful car audio amplifier. To make this achievement possible, JBL enlisted the engineering strength of it’s sister company, Crown. Today, that technology and design philosophy has trickled down to the BPx500.1. At a MSRP of $699, this JBL amplifier is a fine example of engineering excellence.

First Look
The JBL BPx500.1 is a 500-watt, two-channel dedicated subwoofer amplifier. The industrial cosmetics resemble its larger brother, the A6000GTI. Also, like its larger brother, the BPx500.1 is capable of developing full power from speaker loads ranging from 2-ohm stereo operation to 1-ohm bridged-mono operation. It has a fully variable 12 or 24 dB-per-octave low-pass crossover from 32 Hz to 320 Hz. The BPx500.1 also comes with a remote bass control so that you have complete control over your subwoofer system.

A Closer Look
Everything about the JBL BPx500.1 says quality. On one end of the amplifier are nicely appointed connectors for the power and speaker wires. On the other side are the RCA connections and all the amplifier adjustments. It has a see-through Plexiglas top that showcases the interior of the amplifier. Want to show it off more? No problem. The BPx500.1 is designed to accommodate two neon tubes from StreetGlow.

On the technical side, the BPx500.1 includes a filter called DBO (Dynamic Bass Optimization). This fully-variable, high-pass crossover is designed to control your subwoofer’s output with a continuously (20 Hz to 100 Hz) variable "Q" high-pass filter. This uncommon feature for car audio amplifiers is designed to extract the maximum performance of your subwoofer system.

The BPx500.1’s most impressive feature is the way it’s able to deliver power. The amplifier has the ability to run stereo, series bridged mono, and parallel bridge mono. To most of us, series and parallel usually defines how the woofers are wired to the amplifier. In the case of the BPx500.1, the series mode (what we would consider as the conventional configuration for bridging an amplifier) delivers maximum power into impedance loads of 2 ohms and higher. In the parallel bridge mode, the BPx500.1 actually parallels the left and right output for a single low-impedance output channel optimized for 1-ohm performance. This feature is so unique it’s protected by a patent.

Installation
The installation of the JBL BPx500.1 was not difficult. The only difference from installing a regular subwoofer amplifier is configuring the bridge mode as described previously. Luckily, this set-up was well described in the installation manual. There are LED indicators located on the top of the amplifier to let you know that everything is working properly. The four mounting holes for the amplifier are sturdy and well placed. This is a real solid amplifier. The markings on the amplifier are easy to read.

Care must be taken when tuning this amplifier. With an amplifier that has the power and sonic adjustment like the BPx500.1, any wrong settings could potentially damage the amplifier or damage your subwoofers. Due to the capability of the controls of the BPx500.1, I would highly recommend that this amplifier be installed and tuned by an authorized JBL dealer.

Manuals/Web Support
The manual was easy to read with pictures to make the set-up of the different speaker wiring methods quite easy. While, there was a section about the capabilities of the DBO (Dynamic Bass Optimization) circuit, I would have liked to see more information. The company’s Web site, www.jbl.com, was easy to navigate and provided a wealth of knowledge about the BPx500.1. The manual was available for download and the performance specification were clearly presented.

Sound Q & Performance
Weighing in at 11 pounds, the BPx500.1 performed well. True to its claim, the amplifier produced 670 watts, 633 watts, and 635 watts into 4 ohms bridged, 2 ohms bridged, and 1 ohm bridged, respectively. Not only did the BPx500.1 exceed its rated power level, but it did so in three different impedance loads. Way cool. What is not evident in the numbers is how effortless the amplifier appeared to be during these tests. When the amplifier clipped, it did so gracefully — when pushed beyond its limits, it did not get hot or blow the fuses. This amp is solid.

From a sound quality perspective, the BPx500.1 was tight, clean, and effortless sounding. It felt like the amp was saying, "You can’t hurt me, I’m bullet proof." I have never tested an amplifier where it didn’t matter what impedance load it was driving — it never lost composure.

Summary
If you’re looking for just power, there are other amplifiers you can choose from that might be less expensive. If you want an amplifier designed to deliver the most power to any application, has controls designed to get the last ounce of performance out of your subwoofers and act like it is not working hard, then the BPx500.1 is your amplifier.