Commercial Audio

What Is 100V Line?

Commercial audio installations often require large numbers of speakers to be powered from a single amplifier. These systems often called “100V line” are found in most large buildings including shopping centres, schools, offices etc. These audio systems are typically used for general announcing, public address, background music and vitally important fire/evacuation messaging.

A 100V line system is wired up with each speaker being fitted with a transformer on the back of it, this isolates the speakers impedance load from the amplifier. The transformer can be set to a wattage rating, allowing for independent volume level for each speaker. The net result is a 100V line system allows for long ‘strings’ of speakers to hang off a single amplifier output, each speaker is connected to the next one in the circuit by daisy chaining the wiring.

WARNING: Do not EVER mix 100V line speakers with traditional low impedance speakers within the same circuit. 100V amplifiers such as Redback amplifiers are also not designed for powering low impedance speakers and 100V line speakers at the same time.