Monoprice Commercial Audio 4x120W 4ch/4Zone Mixer Matrix 100/70V w/Digital Media Player (No Logo)

Commercial Audio 4x120W 4ch/4Zone Mixer Matrix 100/70V w/Digital Media Player (No Logo)

Simplify the task of running distributed audio for restaurants, hotels, or anywhere large areas need background music and/or paging address systems. Connect hundreds of speakers covering acres of area without the need for large equipment racks.

A constant voltage speaker system differs from a traditional 8-ohm speaker system in that it uses a step-up transformer at the audio source to raise the voltage and lower the current on the transmission line. At the speaker end, a step-down transformer converts the signal back to a normal speaker level voltage. This reduces power loss during transmission, which allows for the use of longer speaker wire runs using smaller gauge wire.

Additionally, a constant voltage speaker system allows for the use of multiple speakers on each channel, without the need for complicated impedance calculations and configurations. In a constant voltage system, all speakers on a given channel are connected in parallel and the complicated impedance calculations are replaced by simple wattage calculations.

For example, if you want to connect two speakers per channel in a traditional 8-ohm speaker system, you must either connect them in series, which results in an overall 16-ohm impedance, or in parallel, which results in an overall 4-ohm impedance. In the first case, the 16-ohms impedance effectively halves the output power of your amplifier, resulting in lower overall volume levels. In the latter case, the 4-ohms impedance means that your amplifier will have to work harder and must be rated as stable at 4 ohms. Adding a third speaker to the mix would complicate it further, producing either a 24-ohm or 2-ohm overall impedance. Note that very few amplifiers are stable under 2-ohm loads, so that is usually not an option.

On the other hand, with a constant voltage system, you consider first the RMS output wattage of the amplifier. This should be reduced by 20% to compensate for insertion loss. For example, if using a 100-watt amplifier, the total load from speakers should not exceed 80 watts.

This amp features three combination XLR/TRS balanced/unbalanced inputs, which can be set to accept a standard microphone input, a microphone input with +48V phantom power, or a line level input. It also has two unbalanced stereo RCA line level inputs. It has four independent 120 watt amplifiers, which can drive 4-ohm loads or a 70V or 100V constant voltage speaker array. A Media Player is included, which features a built-in FM tuner and an mp3 player, which can playback files from a drive connected to the USB port or an SD™ card inserted in the SD/MEDIA slot. It includes thermal, short-circuit, clipping, and overload protection circuits, as well as a ground lift switch. It can interface with external phone systems for telephone paging.

Features:
• Four independent 120-watt amplifiers capable of driving 4Ω loads, as well as 70V and 100V constant voltage speaker arrays
• Three combination XLR/TRS balanced/unbalanced inputs capable of connecting microphone level, microphone level with Phantom power, or line level sources
• Two unbalanced stereo RCA inputs
• Independent gain controls on all inputs
• Any input can be directed to any or all outputs
• Balanced line outputs for each zone
• Built-in media player with FM tuner and mp3 player for playback of files on a connected USB drive or an SD™ card
• Can record FM audio and save as mp3 files on a connected USB drive or SD card
• RS232 serial control
• Can interface with external phone systems for telephone paging
• Thermal, short-circuit, clipping, and overload protection circuits
• 1-watt, 8-ohm amplifier for driving a monitor speaker
• Ground lift option