JL Audio RD900/5+ RD Series 5 Channel Stereo Subwoofer Amplifier 900w RMS

RD900/5+

5 Ch. Class D System Amplifier, 900 W

5-Channel Class D System Amplifier, 70 W x 4 @ 4 Ω + 500 W x 1 @ 2 Ω - 14.4V

Crafted as an all-in-one, total system solution, the RD900/5 is engineered to power a complete audio system consisting of a subwoofer + four satellite system with 900 watts of high-performance sound. Equipped with our exclusive NexD™ switching technology, this complete power package efficiently generates a potent 70 watts of crystal-clear audio into 4 ohms, plus a robust 500 watts for a subwoofer system, all from a single compact chassis. Each pair of main channels is also fully bridgeable, stoutly producing 200 watts of full-range audio bliss (into 4 ohms), creating an ultra-powerful 3-channel amplifier.

Conveniently located on top of the RD900/5, you’ll find a complement of studio-grade signal processing features, all hidden beneath a removable protective cover. Each pair of main channels is equipped with a 12 dB / octave high-pass filter, with a dedicated low-pass filter for its subwoofer channel. All three crossovers offer continuously variable frequency selection from 50-500 Hz, for precise filtering. Dual-range, differential-balanced inputs are also onboard, capable of accepting most input voltage levels, plus automatic turn-on capability (via signal sensing or DC-offset sensing) for maximum versatility.

LED clipping indicators are also standard equipment for each channel section. This all-new, innovative feature lets you easily set your amplifier’s input sensitivity settings, quickly and accurately, with no special equipment needed. The RD900/5 features a durable, black powder-coated finish and a top-mounted, dual-color LED light strip that reports the overall status and condition. With the addition of an RBC-1 remote level control (sold separately), you can conveniently control the subwoofer’s output remotely from the driver’s seat.

NexD™ Switching Technology

NexD™ amplifier technologies produce exceptional audio quality, unsurpassed total efficiency and high power from very compact amplifier designs.

Beginning with the original 'Slash' subwoofer amplifiers, JL Audio has been at the forefront of Class D amplifier design. Our NexD™ switching technology stems from our Class D expertise to deliver outstanding fidelity and efficiency, leading to compact amplifiers that deliver high power and exceptional value.

Let's get a little nerdy... A traditional PWM switching amp design uses a fixed switching frequency and varies the pulse width based solely on the audio input signal to the pulse modulator. This basic approach assumes some ideal conditions, like a rock-steady power supply, that do not necessarily occur in a real, in-car installation. Power supply sag with signal causes distortion at all power levels with these designs, even well below clipping. The cure for this is feedback (a corrective signal sent back to the input side), but this becomes impractical as the audio frequency increases, making it a good solution for band-limited (subwoofer) amps, but not for full-range amplifiers.

Taking the above into account when designing the NexD™ subwoofer amplifiers, we have taken the simple fixed PWM approach and enhanced it with a very high switching frequency: 240 kHz, which is about 4x higher than most Class D subwoofer amplifiers. This pushes the amplifier's bandwidth to at least 500 Hz with minimal distortion and improves efficiency, while keeping typically bulky circuity more compact. Your subwoofers will reward you with tight, rock-solid bass performance.

For the full-range NexD™ amplifiers and channels we applied a variable, ultra-high speed version of the NexD™ technology (switching at well over 400 kHz). In these designs, a self-oscillating modulator with "feed-forward" sends information about the instantaneous power supply voltage to the modulator, combining this with the input signal to cancel out any distortion due to supply voltage fluctuation. This reduces distortion prior to applying feedback, simplifying the overall feedback loop design.

The bottom line is simply great audio: clean, powerful and reliable.