User manual ELECTRO-VOICE S-40 EDS

[. . . ] These high quality components will provide years of listening pleasure when driven at reasonable levels. However, sometimes loudspeakers are accidently over-driven, causing the drive units to fail. To prevent against this, EV engineers have incorporated independent woofer and tweeter protection circuits in the S-40. [. . . ] This shaped signal is sent to the power amplifier with the continuous power set at 160 watts into the 3. 2 ohms EIA equivalent impedance, (22. 6 volts true RMS). Amplifier clipping sets instantaneous peaks at 6 dB above the continuous power, or 640 watts peak (45. 2 volts peak). This procedure provides a rigorous test of both thermal and mechanical failure modes. Protection Circuitry Both the woofer and the tweeter employ independent protection circuits to prevent against accidental overdrive and improve system reliability. In the woofer circuit, a solid state self-resetting switch is activated once the safe level to the woofer is exceeded (approximately 60 watts). This switch then inserts a high positive current coefficient resistor (HPCCR) in series with the woofer. The resistance of the HPCCR increases as 2 S-40 Compact Monitor the drive level to the woofer increases and limits the power being delivered to the woofer. The HPCCR is similar to a lamp and will produce light that is visible thru the port when activated. This is an indication to reduce the gain of the power amp if output compression is to be avoided. The maximum acoustic output is achieved just before the protection circuit is activated. The tweeter protection circuit behaves in a similar manner, except a fixed resistor is used in place of the HPCCR which attenuates the power to the tweeter by approximately 6 dB. Installation Notes On the back of the S-40 are two ·-20" threaded inserts. These are intended to be used with mounting systems which have 23/8" mounting centers, such as the Omnimount Systems Series 25. Care should be taken to ensure that the chosen fixing point is strong enough to support the S-40. Care should also be taken to ensure that the S-40 is not exposed to direct precipitation. If the speaker system is not used with one of the mounting brackets, such as on a bookshelf, then the rubber feet that are included with the S-40 should be attached to the speaker. [. . . ] The Limited Warranty does not apply to burned voice coils or malfunctions such as cone and/or coil damage resulting from improperly designed enclosures. Electro-Voice active electronics associated with the speaker systems are guaranteed for three (3) years from the date of original purchase. Additional details are included in the Uniform Limited Warranty statement. [. . . ]