How much power?

"How much power (wattage) do we need in our church sound system?"

This is a great question, and partly depends on the physical layout of the church, the decor inside and especially the style of worship and requirements from the sound system. However there are some rules of thumb....

Let us start at the top figure... a rock concert ... you need around 10W per person in the venue (generally speaking the number on the fire regulations). So for a 40 person venue such as a village hall you need around a 400W system.

With different styles of music however, you need less power - we typically put in 150W or 250W systems into churches, and augment this with a 150W sub-speaker (for low frequencies) if there is a band. There are obviously more than 30 people in a typical church, but in general churchgoers are not looking to be blown away!

In an outside event you need to probably double the output power because of the lack of reflections from the walls - outside sound just disappears.

"Should the speaker rating match the amplifier rating?"

Great question. The biggest cause of damage to speakers is the use of an amplifier which is not highly rated enough. As you keep turning up and up the amplifier level to get more sound, internal clipping occurs and this can be very bad for the speakers (it also causes headaches in those listening to the sound, even if the speakers are not damaged).

So, again as a rule of thumb, your amplifier should have a higher rating than your speakers. If the speakers have been chosen properly to match the room, the amplifier will never need to be turned up to maximum and therefore everything in the system remains happy.

If you are really worried, it is inexpensive these days to add a device called a "limiter" which ensures that the speakers cannot be overdriven. This is done in such a way as to also ensure that the loud signal remains musical.

Hope this helps!

Tim.

***** Visit us online at www.ChurchPA.co.uk *****
***** Phone 0845 430 9486 *****
Make sense?