ULD-12

About the ULD-12

The Velodyne ULD-12 is a powered subwoofer from Velodyne Acoustics that exemplifies the brand's 'Ultra-Low Distortion' (ULD) philosophy. The subwoofer uses motional-feedback technology, where an accelerometer attached to the voice coil supplies negative-feedback to the amplifier input, extending and flattening frequency response while reducing distortion. The 12-inch driver features an 80-ounce magnet structure and a 2.5-inch voice coil capable of 0.75-inch peak-to-peak linear excursion. The downward-firing driver is mounted on the bottom of a sealed cabinet, allowing the subwoofer to function as a small end table or plant stand. The integrated 250-watt Class D switching amplifier operates efficiently with minimal heat generation and requires no power transformer. The system includes a separate controller unit that connects between the preamplifier and power amplifier, or directly to speaker outputs. Originally priced at $950 USD when new, the ULD-12 represents a classic design from Velodyne's dominant era in the 1980s-1990s subwoofer market. The product is no longer manufactured, though used units remain available in the secondary market.