Subwoofers — Velodyne SPL-X 18

The SPL-X 18 is one of four sealed active subwoofers in the SPL-X series from Velodyne Acoustics, the Hamburg company that uses this range to bring back its SPL name. The other sizes carry 10, 12 and 15 inch woofers, and Velodyne aims SPL-X at cinema rooms, studios and living spaces. Carbon drivers, DSP and Class D power are common to all four, while the 18 has the highest amplifier rating of the four. UK list pricing is GBP 6,999.

Key specs that matter

Velodyne rates the internal Class D stage at 1800 W RMS with 2500 W peak. Velodyne specifies 20 Hz to 180 Hz within 3 dB, and 13 Hz to 220 Hz within 10 dB. The low-pass control spans 30 Hz and 200 Hz, with slopes of 12, 24, 36 or 48 dB per octave, and a delay control covers 0 to 500 ms. The cabinet measures 550 mm across, 560 mm in height and 620 mm in depth. Net weight is 55 kg, and the boxed unit comes to 62 kg. Supply voltage can be 115 V or 230 V.

Engineering and use context

An 18 inch carbon fibre cone is suspended on a dual spider in a basket with three ventilation channels, which cool the drive and hold the structure steady when the amplifier runs near its limit. Behind it sits a triple ferrite magnet system and a four-layer voice coil of 102 mm. The enclosure is closed rather than ported and is made of reinforced HDF. Velodyne built the series around DSP control, and through the free app the listener can change level, crossover point, phase and a fully parametric 6-band EQ, switch in subsonic and high-pass filters and recall presets without leaving the seat. Auto power-on is included, and its trigger sensitivity is adjustable, so the sub switches on only when a real signal arrives.

Pairing

The rear panel accepts RCA stereo or LFE, XLR stereo or LFE and a stereo high-level feed from speaker terminals. That covers the LFE output of a multichannel AV processor, a balanced run from a pro-audio preamp over a long cable and a two-channel amplifier that lacks a dedicated sub output. RCA and XLR outputs let a further subwoofer be connected in a chain, which suits a large home theatre where two units share the low end. The selectable slopes and the app's high-pass filter help the SPL-X 18 hand over cleanly to towers or to compact speakers.

Alternatives

The Velodyne SPL-X 15 uses a smaller carbon fibre woofer and a 1500 W RMS amplifier in a smaller 470 x 470 x 580 mm cabinet that weighs 45 kg.