Indoor/Outdoor PA Horn Speaker 20W Loud Sound Aluminum Grey

We are hooking this up to a three wire system. Which wire should we not use? We have black, white and ground.

If you're referring to standard household wiring, you should not leave any of the three wires unused. The PHSP101T requires proper connection of hot (black), neutral (white), and ground (green/bare copper) for safe operation.

Before connecting anything, verify the wiring diagram for your specific installation. If you're asking which wire from the PHSP101T connects to your black, white, and ground wires, please provide a photo or tell us the wire colors coming from the PHSP101T so we can give the correct wiring guidance.

Can the transformer be bypassed for use as an 8 Ohm speaker?

Look for the ohms wire tap

Can I use this speaker in a 25 volt system?

This speaker only runs on 70 volts

How to hook up the wires

70 Volts System is intended for multiple speaker set ups

Horn Speaker requires a 70 volts Amplifier Receiver
PHSP101T has 3 70 Volt Transformer Tapping 20Watts, 10Watts, and 5Watts
The selection of tapping will vary depending on the wattage of the amplifier and the number in quantity of the horn speaker
EX. Amplifier 200Watts @ 70volt
     1. Horn tapping @ 5 watts x 40 Horn speaker = 200Watts
     2. Horn tapping @ 10 watts x 20 Horn speaker = 200Watts
     3. Horn tapping @ 20 watts x 10 Horn speaker = 200Watts