S1520S

With YST, a feedback loop around the amplifier is used to create a negative impedance, and the necessary speaker damping is restored electronically. The result is a powerful, very tight, well-behaved pass response from a modest-sized enclosure and transducer.

The S1520 is a trapezoidal enclosure const. of poplar plywood (very strong and non-resonant). Fabricated in Yamaha's Thomaston, Georgia factory. The speaker cabinets have an unobtrusive, black splatter finish chosen because it is durable and easily retouched in the event it is chipped or scuffed during a tour. A metal mesh grill protects components from damage. We dip-coat the grill with black plastic to reduce unwanted resonances. It is also equipped with a Neutrik NL-4 Speak On connector.

By raising the crossover point from between 800 Hz and 1,000 Hz to 1,200Hz, we could reduce the range over which the horn and driver are required to function. We choose a compression driver with a 2.8 inch aluminum diaphragm. We designed the horn with a 1.4 inch throat.

We developed two versions of the horn; one with 105 degree coverage of short-throw use, and one with 60 degree coverage for long-throw and array building. The horns may be interchanged among cabinets so you can custom-configure the system.

To ensure that the coil remains perfectly aligned, even at very high peak excursions, the coil is suspended by a unique double multi-spider. The spider is the suspension component that aligns the cone and voice coil within the magnetic structure.

The S1520S cabinet includes three Aeroquip rigging fittings on top, and another three on the bottom. Each is anchored internally to a steel 90 deg. angle bracket that is also bolted into the adjacent side of the enclosure. The 7-ply poplar plywood provides carry-through strength for an ultimate load of more than 3 tons. A 5:1 loading safety factor is advisable, and Yamaha therefore recommends hanging no more than 3 tiers of speakers vertically regardless of the width of the array.