Speaker Wiring - 70 Volt Transformer systems
From here, any time that you want to add a speaker, you need to have another transformer that allows you to connect to the 70 Volt Signal line, and then, connect the other side of the transformer to the speaker.
You'll note that the above schematic shows colored taps on t transformer that is associated with each speaker.
These taps are used to define the amount of power going to each speaker.
This allows you to set some speakers louder than others, if there is a need to do that, however, typically all
the speakers are set on the same taps (with the same loudness settings).
You will find that most of these systems limit the amount of signal to any individual speaker to no more than 15 watts. Odds are very good that when set, you will use a 2 to 5 watt tap for each speaker.
As you would with any audio system, you will need to figure out how many speakers that you want to use and then divide that into the wattage of your power amplifier - you should not exceed that load, otherwise, you will encounter distortion.
Because of the low wattage limitations of the individual speakers, this set up is normally used in office sound systems and areas where you only want to hear background music, or occasional messages to everyone within a facility. They are rarely used for Pro-Audio systems. Higher powered transformers are available, but they tend to be very expensive. With this in mind, its easy to see that this is not a usable system if you need Sub-Woofers (they need far too much power).
You can't miss the transformer - its stuck right onto the speaker.
For horns that are used outdoors, the transformer will not be as obvious, as it is usually built into to the horn housing to protect it from weather. These often require that a cover be removed to have access to the taps on the transformer. Many outdoor horns do not have a transformer (they are simply a horn that is wired as any other speaker) - you can add one if needed to any 4, 8 or 16 ohm audio speaker/horn. Many electronics suppliers sell the transformers seperately - all will require some form of weatherproof/waterproof protective housing if mounted outside of the horn in a place exposed to the outdoors.
Note: You may find 100 Volt systems as well. These use the same concepts, however, they use 100V transformers instead of 70V transformers. Use all the same type in your system.
Some advantages of 70 Volt systems:
Some disadvantages of 70 Volt systems:
Questions? Comments? .
© 2000 Shavano Music Online