Looping, Polarity, and Attenuating Audio Input Module
This module has a balanced, female XLR audio input connector, a male XLR loop connector, an input polarity switch, and a level attenuator knob. With the input polarity switch in the up (+) position, pin 2 is hot relative to pin 3, resulting in a positive pressure wave when a positive signal is applied to pin 2. With the switch down (–), pin 3 is hot relative to pin 2, resulting in a negative pressure wave when a positive signal is applied to pin 2. The level attenuator knob operates between 0 dB (no level attenuation) in a fully clock- wise position to –12 dB in a fully counter-clockwise position.
Remote Monitoring System
The UM-P can be equipped to operate with the Remote Monitoring System (RMS) network and software ap- plication. RMS displays signal and power levels, driver and cooling fan status, limiter activity, the state of the polarity switch, attenuator level, and amplifier tem- perature for all speakers in the network on a Windows- based PC. RMS is an excellent field-diagnostic tool that removes the guesswork from troubleshooting during a performance. All Meyer RMS-compatible speakers use the same RMS module so they can be easily exchanged between speakers (depicted on back page). Installing an RMS module requires only a Phillips screwdriver. Contact Meyer Sound for more information about RMS.
Amplification, Limiting, and Cooling System
Amplification and Limiting
Each driver in the UM-P is powered by one channel of a proprietary Meyer Sound amplifier utilizing comple- mentary power MOSFET output stages (classAB, bridged, 350 Wrms/ch). Each channel has a limiter that prevents driver over-excursion and regulates the temperature of the voice coil. The limiters protect the drivers without the glaring compression effects imposed by typical limiters, allowing high SPLs across each driver’s entire frequency range. Limiter activity for the high and low channels is indicated by two yellow Limit LEDs on the rear panel (the high limit is above the low limit LED).
The UM-P performs within its acoustical specifications and operates at a normal temperature if the limit LEDs
are on for no longer than two seconds, and off for at least one second. If either LED remains on for longer than three seconds, that channel incurs these negative consequences:
•Increasing the input level will not increase the volume.
•The system distorts due to clipping and nonlinear driver operation.
While the UM-P limiters fully protect the system under overload conditions and exhibits smooth sonic charac- teristics, we recommend that you do not intentionally drive the UM-P into continuous limiting to attain com- pression effects.
For applications where large amounts of compression are required, we recommend using an outboard com- pressor/limiter for greater control of limit and com- pressor effects.
Amplifier Natural Convection Cooling System
The UM-P employs a natural convection cooling sys- tem that depends on air flow from below the cabinet over the heatsink. Allow for proper ventillation of fresh air when using the speaker.
If the temperature of the heatsink reaches 85°C (185°F), the On/Temp. LED on the rear panel turns from green (On) to red (Temp.) and the limiter threshold is lowered to a safe level to prevent the amplifiers from overheat- ing. Under high temperature conditions the limiter thresholdisreducedto6dB. Whentheheatsinktmeperature decreases to 75°C (167°F), the On/Temp. LED changes from red to green and the limiter threshold returns to normal.
!The heatsink gets too hot to touch during normal operation. Use extreme caution when approaching the rear of the cabinet.
Fan Assembly Kit
While convection cooling is adequate for most appli- cations, driving the UM-P into frequent limiting under severe temperature conditions, or where ventilation is restricted, an optional fan kit is available to maintain a safe operating temperature:
The easy-to-install fan, powered by the 24V Fan rear panel connector, blows air directly onto the heatsink. The fan speed increases as the heatsink temperature rises, which maintains a safe operating temperature with minimal fan noise. Contact Meyer Sound to order the fan kit.
