Louroe Line Powered MicrophoneBy Brian Rhodes, Published on Apr 01, 2012
Many IP video cameras contain microphones that do not provide enough fidelity to record more than muffled audio. When high-quality audio recording is required, external microphones must be installed. Unfortunately, these external microphones often must be powered from additional power supplies. Louroe Electronics has announced a new line of microphones designed to eliminate the need for external power. In this note, we examine the first product in this new line.
Louroe Electronics, based in California, manufacturers a variety of products for use in audio monitoring and intercom applications. As we have previously noted, the company is widely recognized among security integrators as a specialy vendor of audio recording hardware for video surveillance.
Here's a snapshot of Louroe's new microphone, model number 'LE-778':
Notice the microphone is designed into a standard coverplate for a single gang junction box. This type of design results a vandal-resistant install that can be mounted inconspicuously within walls.
The LE-778 is an 'electret' type of microphone that requires no external pre-amp like the 'standard condenser' type. All pre-amp voltage required for use is supplied by the host device. The device cable is preterminated in the standard 3.5mm 'mini jack' connector compatabile with audio inputs on many IP cameras.
Any IP camera furnished with this type of jack is able to make use of this microphone. However, the location of this jack will depend on the type of camera, and determining if enough clearance exists for the connector plug inside of a housing or on the backside of a camera is subject to field verification. See picture below detailing the standard type of 'AUDIO IN' jack supporting this microphone:
Line Powered vs. Phantom Power
The LE-778 is 'line powered', meaning the camera supplies power to the microphone through the transmission cable. Many 'line powered' devices operate on low voltages, typically 3 to 5 VDC. This transmission method is sometimes confused with 'Phantom Power' that also uses one cable, however uses a much higher voltage (48 VDC). An IP camera with an 'audio input' jack is not designed to produce that much voltage.
Line powered microphones are not expensive or difficult to source. However, Louroe has packaged their microphone in a mount that lends itself to better listen positioning and protection than simple commodity type microphones.
The LE-778 has an MSRP of $139 USD, which is less than half the cost of Louroe's closest externally powered ASK-4KIT #101 [link no longer available] with an MSRP of $330 USD.