Velodyne SPL-X 15

The 15-inch model is the flagship for private cinema rooms and demanding stereo systems. Between the 1500 W RMS Class D amplification, the carbon cone driver, and the DSP controllable via mobile app, this sealed subwoofer brings together technologies developed since the legendary DD (Digital Drive) and SPL Ultra series.

A carbon driver designed for long excursion

The 38 cm driver uses a carbon fiber cone, a material chosen for its rigidity and light weight. This combination limits cone deformation at high levels, reducing harmonic distortion even during the most dynamic passages.

The suspension employs a dual spider that keeps the voice coil perfectly aligned with the magnetic field axis, even at large excursions. The voice coil itself measures 102 mm in diameter and uses four layers of wire. This configuration offers a large magnetic interaction surface with the triple ferrite magnet system, resulting in better conversion of electrical energy into mechanical movement.

The driver basket incorporates three ventilation channels. Air flows freely behind the cone and around the coil, dissipating the heat generated during prolonged high-volume use. Without this system, electrical resistance would increase with temperature and gradually compress dynamics.

A sealed enclosure for precise response

Velodyne has always favored sealed subwoofers over bass-reflex designs. The SPL-X 15 is no exception to this tradition. The HDF (high-density fiberboard) enclosure features reinforced construction to minimize cabinet wall vibrations as much as possible.

A sealed subwoofer has one main advantage: the impulse response remains clean. The cone is naturally damped by the trapped air cushion, without the characteristic port delay. In return, extending into the infrasonic range requires more power and a driver capable of large excursions, hence the interest of the motor system described above.

The dimensions (470 × 470 × 580 mm for 45 kg) remain compact given the cone diameter and onboard power. The black lacquered cube features slightly rounded edges and a removable fabric grille on an MDF frame.

1500 watts RMS and integrated digital processing

The Class D amplifier delivers 1500 W continuous and can reach 2000 W peak. This power reserve ensures comfortable headroom during level peaks, whether for action movie impacts or kick drum attacks in an orchestral recording.

The built-in DSP allows fine-tuning of the subwoofer’s behavior. The low-pass filter covers a range from 30 to 200 Hz, with four selectable slopes (12, 24, 36, or 48 dB per octave). This flexibility simplifies integration with satellite speakers of various sizes and crossover points. A delay setting from 0 to 500 ms compensates for timing offsets related to subwoofer placement relative to the listening position or main speakers.

Automatic calibration and app control

A supplied measurement microphone with tripod allows you to launch the AutoEQ procedure from the Velodyne Acoustics AutoEQ SUB app (iOS and Android). The subwoofer emits a series of test signals, the microphone captures the room response, and the DSP calculates an appropriate correction.

The app then displays the measured and corrected response curve, helping you determine whether the subwoofer placement suits the room acoustics. A six-band parametric equalizer remains available for additional manual adjustments. Presets (Movie, Jazz/Classic, Rock/R&B, Game) provide quick starting points depending on the content being played. A night mode reduces overall level while preserving the perception of low frequencies at moderate volume.

The Bluetooth connection between phone and subwoofer saves you from getting up to change settings: volume, crossover frequency, phase, and EQ are all controlled from the listening seat.

Comprehensive connectivity for all systems

The rear panel provides stereo and LFE RCA inputs, stereo and LFE XLR inputs, and a high-level input via binding posts. This last option is of interest for stereo setups without a dedicated subwoofer output: the signal is taken from the amplifier’s speaker terminals and filtered by the subwoofer’s DSP.

RCA and XLR outputs allow you to daisy-chain a second subwoofer or pass the signal to another device. The power mode selector (Auto, 12 V Trigger, Always On) adapts to each system’s habits. In Auto mode, the subwoofer detects the presence of a signal and powers on automatically. Detection sensitivity is adjustable to avoid unwanted standby with low-output-level sources.

The power supply accepts either 115 or 230 V, a real advantage for international installations or second-hand purchases from other markets.

Technical specifications

Speaker and enclosure

• Driver: 15″ high-performance
  • Three-channel ventilated basket
  • Carbon fiber cone
• Suspension: double spider for optimal control
• Voice coil: 4″ / 102 mm, four layers
• Magnets: triple ferrite system
• Enclosure: sealed HDF, reinforced construction to minimize resonances

Amplification

• Type: Class D
• RMS power: 1500 W
• Peak power: 2000 W

Signal processing

• Frequency response
  • ± 10 dB: 15–250 Hz
  • ± 3 dB: 22–180 Hz
• Low-pass filter: adjustable 30–200 Hz, slope 12 / 24 / 36 / 48 dB per octave
• Delay: 0–500 ms
• AutoEQ DSP: automatic calibration via microphone to adapt bass response to the room acoustics

Connectivity

• Inputs: stereo / LFE RCA, stereo / LFE XLR, stereo high-level input
• Outputs: stereo / LFE RCA, stereo / LFE XLR

Features

• Control via mobile app
  • Volume adjustment
  • 6-band equalizer
  • Subsonic and high-pass filters
  • Presets
• Automatic power-on with adjustable sensitivity
• Power selector: Auto / Trigger / On

Power supply and finish

• Voltage: 115–230 V
• Grille: black fabric with MDF frame

Dimensions and weight

• Dimensions (H / W / D): 470 x 470 x 580 mm
• Weight: 45 kg
• Shipping weight: 50 kg