Velodyne SPL-X 18

With a 46 cm driver and a 1800 W amplifier, this sealed subwoofer is the most powerful model in the SPL-X series. This range, unveiled at ISE 2025 in Barcelona, succeeds the SPL Ultra series and inherits the DSP technology that Velodyne has been developing since its DD series, the first on the market to feature automatic calibration back in 2003.

A 15 kg motor designed for long excursion

The SPL-X 18 driver is built around a triple-ferrite magnet assembly weighing 15 kg. The 102 mm, four-layer voice coil works together with a dual spider suspension to keep the cone perfectly aligned, even at very high excursions. This carbon fiber cone combines low mass and rigidity: it moves quickly while resisting the deformations that cause distortion.

The supporting basket features three ventilation channels. This system dissipates the heat generated in the voice coil and prevents air compression behind the cone—two phenomena that usually limit the dynamics of long-throw drivers.

A sealed enclosure for superior timing accuracy

The HDF (high-density fiberboard) cabinet uses a sealed configuration rather than bass-reflex. This choice requires a more powerful amplifier to reach the same sound pressure level, but provides two measurable advantages: a faster impulse response and predictable behavior down to the very lowest frequencies. The reinforced construction and panel thickness (25 to 35 mm depending on the area) reduce unwanted cabinet vibrations.

At ±10 dB, the frequency response extends down to 13 Hz. The usable range at ±3 dB goes from 20 to 180 Hz. These figures place the SPL-X 18 in the category of subwoofers capable of reproducing the infrabass of modern movie soundtracks and the deepest notes of an organ or synthesizer.

DSP as an integration tool

The 1800 W RMS Class D amplifier (2500 W peak) includes a digital signal processor whose settings go far beyond simple volume and phase. The low-pass filter is adjustable from 30 to 200 Hz with four selectable slopes (12, 24, 36, or 48 dB per octave). A delay setting from 0 to 500 ms allows precise time alignment of the subwoofer with the main speakers in large rooms.

The AutoEQ function uses the supplied measurement microphone to analyze the room response and apply corrections. The mobile app (available on iOS and Android) gives access to the 6-band parametric equalizer, subsonic and high-pass filters, as well as preset modes (Movie, Jazz/Classic, Rock/R&B, Game). These settings can be adjusted from the listening position via Bluetooth.

Connectivity ready for any system

The rear panel provides RCA and XLR inputs for stereo and LFE, plus a high-level input for amplifiers without a pre-out. The same connectors are available as outputs for daisy-chaining multiple subwoofers or sending the signal to another device. A three-position switch (Auto/Trigger/On) manages power, with adjustable sensitivity in Auto mode.

Technical specifications

Driver and cabinet

• Driver: high-performance 18″
  • Three-channel vented frame
  • Carbon fiber cone
  • Dual spider for maximum control
• Voice coil: 4″ / 102 mm, four layers
• Magnets: triple ferrite magnet system
• Enclosure: sealed HDF cabinet, reinforced construction to minimize resonances

Amplification and signal processing

• Amplifier type: Class D
• Continuous power (RMS): 1800 W
• Peak power: 2500 W
• Frequency response
  • ±10 dB: 13 – 220 Hz
  • ±3 dB: 20 – 180 Hz
• Low-pass filter: adjustable 30 – 200 Hz, slope 12 / 24 / 36 / 48 dB per octave
• Delay: 0 – 500 ms
• AutoEQ DSP: automatic room acoustic calibration via microphone

Connectivity and control

• Inputs: stereo / LFE RCA, stereo / LFE XLR, stereo high-level input
• Outputs: stereo / LFE RCA, stereo / LFE XLR
• App control: volume adjustment, 6‑band equalizer, subsonic and high-pass filters, presets

Power supply and finish

• Automatic power-on with adjustable sensitivity
• Power mode selector: Auto / Trigger / On
• Mains voltage: 115 – 230 V
• Grille: black fabric with MDF frame

Dimensions and weight

• Dimensions (H x W x D): 550 x 560 x 620 mm
• Weight: 55 kg
• Weight with packaging: 62 kg

General information

The SPL-X 18″ features an ultra high-performance carbon fiber driver, a powerful Class D amplifier, an AutoEQ DSP for automatic room acoustic calibration, comprehensive connectivity, and app-based control.