Mackie DLM12S Owner's Manual - Page 13

Owner's Manual Smart Protect There are advanced DSP protection mechanisms designed into the DLM12S to safeguard the subwoofers and amplifiers from inadvertent damage. The protection circuits are designed to protect the subwoofers under reasonable and sensible conditions. Should you choose to ignore the warning signs [e.g. excessive distortion], you can still damage the speaker in the DLM12S by overdriving it past the point of amplifier clipping. Such damage is beyond the scope of the warranty. Limiting The driver has its own compression circuit which helps protect it from damaging transient peaks. The compressor is designed to be transparent and is not noticeable under normal operating conditions. The front LED will pulse when in limit. Turn the volume down! Overexcursion Protection A 36 dB/octave high-pass filter at 32 Hz just prior to the low-frequency amplifier prevents very low frequencies from being amplified. Excessive low-frequency energy below 29 Hz can damage the woofer by causing it to "bottom out," also know as overexcursion, which is equivalent to a mechanical form of clipping. Thermal Protection All amplifiers produce heat. The DLM12S is designed to be efficient both electrically and thermally. The amplifier module has internal heatsinks and a digitally controlled variable speed fan. As the DSP recognizes varying internal heat levels, it will turn on at an appropriate speed to draw cool air in over the amplifier and exit via the side vents. In the unlikely event of the amplifier overheating, a built-in thermal switch will activate, muting the signal and ramping the fan up to top speed. An error message will also appear on the OLED Display. If the thermal switch activates, try turning down the level control a notch or two on the mixing console (or the back of the subwoofer) to avoid overheating the amplifier. Be aware that direct sunlight and/or hot stage lights may be the culprit of an amplifier overheating. FYI The FYI screen displays the latest UI version, DSP version, Amp B+ [voltage] and current temperature. Nothing may be changed or updated here, just an FYI, as stated. This screen is displayed when pressing the VOL [10] and MEM buttons [14] simultaneously. AC Power Be sure the DLM12S subwoofer is plugged into an outlet that is able to supply the correct voltage specified for your model. It will continue to operate at lower voltages, but will not reach full power. Be sure the electrical service can supply enough amperage for all the components connected to it. We recommend that a stiff (robust) supply of AC power be used because the amplifiers place high current demands on the AC line. The more power that is available on the line, the louder the speakers will play and the more peak output power will be available for a cleaner, punchier bass. A suspected problem of "poor bass performance" is often caused by a weak AC supply to the amplifiers. Be aware of any error messages that may be displayed on the OLED Display. Overvoltage, for example. When the amplifier has cooled down to a safe operating temperature, the thermal switch resets itself, and the DLM12S subwoofer resumes normal operation. Never remove the ground pin on the power cord or any other component of the DLM12S subwoofer. This is very dangerous. Owner's Manual 13