Subwoofer Reviews

Velodyne introduced their series II subwoofer line in the fall of 1988, and it seems timely to review their largest, most powerful unit, the ULD-18. As the line's flagship, this Velodyne subwoofer represents the most sophisticated and expensive system offered by the company. It is sold as a system, complete with driver, enclosure, amplifier, control unit, electronic crossover, and servo cable and circuitry. Velodyne's unique servo circuitry, manufacturing techniques, and aggressive sales technique emanate from the company's designer, David Hall.

I was so impressed by the Nelson-Reed 8-04/B loudspeaker's low-end range that I seriously doubted the add-on subwoofers could add enough of significance to be cost-effective.

I was wrong.

Two of the subwoofers were provided, along with the necessary electronic crossover unit. Each 1204 unit contains four 12" woofers in a very solid sealed enclosure, with two facing to the front and two facing the rear. The electronic crossover has three controls, besides the AC power switch: a hardwire (footnote 1) bypass switch, a stereo/mono switch, and a subwoofer level control. In the stereo mode, the low frequencies are kept separate, left from right; in mono mode, they are blended together for feeding to a single subwoofer. I will not resurrect the question of whether or not it is important to maintain stereo separation into the LF range, except to echo N-R's observation that there is no LF separation on analog discs to begin with; the lows are mixed together, to limit vertical excursions of the cutting stylus that could cause it to rise above the disc surface or, worse, dig into the aluminum base of the master disc.

Welcome back, Ladies and Gentlemen, to the continuing saga of the Englishman's Search for True Bass. In the previous episode (footnote 1), you witnessed Our Hero tussling with the problems of ported vs sealed-box woofer loading for full-range speaker systems. His conclusion? That ported designs may offer low-frequency quantity but it always seems to be at the expense of quality. If it's bass quality you want, you are better off with well-tuned sealed boxes, which explains why he is an unashamed fan of relatively small speakers with fast, tight upper bass. In this month's thrilling installment, JA—stiff upper lip thrust forward—wrestles with the problems of extending the bass response of his preferred speakers with a subwoofer from the Californian company of Sumo! Now read on . . .