[. . . ] Two M6 and two 3/8" threaded inserts add to the speaker's flexibility. Connections are made to recessed color-coded, spring-loaded terminals. Wattage taps, voltage adjustments and 4-ohm operation are selectable by means of two detented rotary switches. [. . . ] The low-frequency transducer shall be a cone type loudspeaker having a carbon fiber cone with a diameter of at least 4. 75 inches (120mm). It shall present a nominal load impedance of 8 ohms to the crossover network. The high-frequency driver shall be a titanium metalized dome tweeter having a diameter of at least 0. 5 inches (13mm). Its voice coil shall be treated with Ferrofluid® to aid in cooling. It shall present a nominal load impedance of 8 ohms to the crossover network. The system shall be crossed over by an internal, highlevel, passive network having a response of 12 dB/octave. The low-pass section of the network shall have minimum inductance in series with the low-frequency driver. A dynamic high-frequency protection circuit based on a low-value, low-mass filament resistor shall limit the current available to the high-frequency driver. The crossover network shall present a nominal 4-ohm load impedance to the power amplifier or built-in constant voltage transformer. The constant voltage transformer shall have multiple power taps at 1, 2. 5, 5, 10 and 20 Watts. Two detented rotary switches shall be provided on the input panel to adjust the power and voltage taps of the transformer. The voltage tap switch shall have a position to bypass the transformer and allow the loudspeaker to present a 4-ohm load to a directly coupled power amplifier. It shall be constructed using high density polystyrene and finished with black (or white), scratch resistant paint. A full size, detachable, perforated steel grille, finished in black (or white) scratch resistant paint shall be provided. [. . . ] The two-way loudspeaker system shall be a model MR3STK (MR3SWTK - white) manufactured by Mackie Industrial. (continued Architects' & Engineers' Specs) MR3STK Electronic files for this product available at: www. mackieindustrial. com This Specification Sheet Quick-Start Manual MR3STK. PDF MR3STKQS. PDF www. mackieindustrial. com 16220 Wood-Red Rd. NE, Woodinville, WA 98072 USA 888. 337. 7404, fax 425. 487. 4337, industrial@mackie. com UK +44. 1268. 571. 212, fax +44. 1268. 570. 809, uk@mackie. com ITALY +39. 0522. 354. 111, fax +39. 0522. 926. 208, italy@mackie. com FRANCE +33. 3. 8546. 9160, fax +33. 3. 8546. 9161, france@mackie. com GERMANY +49. 2572. 96042. 0, fax +49. 2572. 96042. 10, germany@mackie. com Mackie Designs continually engages in research related to product improvement. New material, production methods, and design refinements are introduced into existing products without notice as a routine expression of that philosophy. [. . . ]