User manual POLK AUDIO MM1540 README

[. . . ] Similarly, we recommend using amplifiers and receivers with rated power above the Power Handling limits of our speakers because having extra power available for short term peaks is conducive to better sound quality, maximum dynamic range and effortless high volume output. But we strongly urge you not to use the full power of your amplifier or receiver for daily listening. Loudspeakers can be damaged when an amplifier, regardless of its wattage, is made to play at higher listening levels than its power can clearly produce. [. . . ] With the coils wired in series and the speakers wired in parallel, 3 dual 4 Ohms speakers will present a 2. ENGLISH PRECONDITIONING PERIOD Mobile Monitor Subwoofers will achieve even greater performance once they are thoroughly broken in. To break in your new MM Subwoofers, play 20 to 30 hours of music at moderate levels. Php OPTIMAL CROSSOVER SETTING We recommend using an active crossover with a 12 to 24dB per octave low pass filter slope, and setting it to an initial setting of 80 to 90Hz as a good starting point. INVERTING PHASE Depending on the placement of your subwoofer enclosure and associated components, it may be necessary to invert the phase of one or another of your system's connections in order to gain better subwoofer/mid-bass blending. Inverting the phase simply means switching the positive connections with the negative connections at the amplifier. If you choose to do this, invert the phase of only one set of speakers (either your mains, or your subs, never both). LOW FREQUENCY CUT-OFF FOR MID-RANGE SPEAKERS IN SYSTEMS WITH SUBWOOFERS Now that you have a subwoofer in your system, you may want to decrease the amount of bass going to your midrange speakers. This will get you better mid-range sound and increase the power handling. There are two ways to roll off the bass before it gets to your mid-range speakers. One way is to use a "bass blocker, " a capacitor placed in series with the speaker input. Bass blockers are installed in series, one end connected with the positive lead from your amplifier and the other end connected to the positive lead of each of your speakers. Bass blocker capacitors (200 microfarad @ 100V, non-polarized) are available at any Radio Shack or electronic parts supply house. The other route is to use an electronic crossover device that allows filtering below 100Hz or so. To the speaker, contact the authorized Polk Audio dealer where you bought your speakers. Authorized Polk Audio dealers are the best source for advice and assistance. Polk Audio's Customer Service Department is available from 9am­6pm, EST, Monday through Friday, at 800-377-7655 (US & Can only, outside the US call 410-358-3600). Please do not hesitate to call us if you have questions about your speaker system. [. . . ] This Warranty does not include service or parts to repair damage caused by accident, disaster, misuse, abuse, negligence, inadequate packing or shipping procedures, commercial use, voltage inputs in excess of the rated maximum of the unit, cosmetic appearance of the cabinetry not directly attributable to defects in materials or workmanship, or service, repair, or modifications of the Product which has not been authorized or approved by Polk Audio. If this Product is defective in materials and workmanship as warranted above, your sole remedy shall be repair or replacement as provided above. Be liable to you for any incidental or consequential damages arising out of the use or inability to use the Product, even if Polk Audio, Inc. [. . . ]