How to tell how loud a sound system will be

[RJP]

We are thinking of buying a sound system for the Church band. We have a standard band (drums, elec guitar, elec bass, congas/timbales and lead singer with 2 backups) - my question is this: is there any way to tell how loud a sound system will be based on the specifications???? Does the number of watts give an indication of volume? Or is there some other specification we should be looking at?

Any help is appreciated. We need to be loud enoug for a Chapel that has seating for about 200, but we want extra volume so we can do some things outside in the future. We're looking at one with 500 watts, but it's not something that is easy to test in the store.

Any help is appreciated.

Thanks,

Russ

[Captain Bb]

You might get by with 500 watts for a 200 seater indoor gig but you're going to need at least double that for outdoors. Better to have plenty in reserve, rather than not enough, so I'd be looking for something in the 1200 to 1500 watt range.

Wattage is an indication of loudness but there are other factors that affect it too - speaker efficiency, number and type of speaker arrangement, etc.

[SAguitar]

500 watts won't do what you're looking for. Shucks, we have 800 watts just in the bass amp we use onstage, and that's just for monitor purposes, and not s'posed to be projected into the house too much. But then, our room holds about 800 when full. I'd still say that 500 is way too little, especially if you're going to mic the drums and bass, plus everything else. Headroom is very important, you'll want to have a lot of that. Overdrive may sound good in a nice little tube amp, but it is quite ugly when you hear distortion in the house sound. I'd suggest you find someone in your area who is a professional sound reinforcement tech, and ask them to come assess your situation before you jump into anything.

[ElijahBaley]

500 watts won't do what you're looking for. Shucks, we have 800 watts just in the bass amp we use onstage, and that's just for monitor purposes, and not s'posed to be projected into the house too much. But then, our room holds about 800 when full. I'd still say that 500 is way too little, especially if you're going to mic the drums and bass, plus everything else. Headroom is very important, you'll want to have a lot of that. Overdrive may sound good in a nice little tube amp, but it is quite ugly when you hear distortion in the house sound. I'd suggest you find someone in your area who is a professional sound reinforcement tech, and ask them to come assess your situation before you jump into anything.

I am inclined to agree with that assessment. There is a very good chance that you will be called upon to do at least some outdoor work and 500W is just not going to do it. For any gig you do, if your volume level is above 50%, then you need a bigger amp but in general, 1200W to 1500W is a starting point, about 1000W per channel would give you the headroom for almost anything you are likely to do. If you need concert sound, you can hire the gear with the required grunt.

[RJP]

thanks for your help!!! Does it make any differnce that we are probably going to use the system only for the vocals and play everything else through separate amps?

[ElijahBaley]

thanks for your help!!! Does it make any differnce that we are probably going to use the system only for the vocals and play everything else through separate amps?

That's how you would use it at first. Eventually, you put all the amps through a mixer using microphones in front of the speakers and then you can independently control the levels of each amp by a qualified sound engineer on the mixing desk. Of course most bands (or so it seems) start with someone who knows as much about mixing desks as we do about brain surgery but occasionally an experienced engineer turns up and actually does a great job of adjusting the levels. Sorry about the cynicism there. Jokes aside, it is very hard to get the levels right by getting someone to go around the stage and adjust all the amps directly. Guitarists in particular are notorious for being disproportionately louder than everyone else. Takes an awful lot of experience to get separate amp levels right. It comes together with a mixer and really big PA system

[ElijahBaley]

Just going back to your original question - 500 watts would be nice for pre-recorded between-set music but your vocal PA needs to be at least twice that, especially for outdoor use. If you have 100W guitar amps, you will need 800W bass amps to match them. Your vocal amp needs to be powerful enough to be able to override the music amps without distorting, and that means about 1000W or more.

That is just a guide. You could do it with less indoors but I can tell you it would fail miserably outside. Sound power drops off quickly in open air so you need some big guns that will handle it.

Acoustic drums are pretty loud indoors but when you start using the power required to get the music sound out in open air, the drums start to fall away pretty quick too. They need to be miked up as well and we come back to a big PA with a mixer that has lots of channels.

Yes people do get by on guitar and bass amps and a moderate PA for vocals. And sometimes they do it outdoors with some success depending on the acoustic properties of the stage. But if you are planning outdoor gigs, you have to plan BIG

[Herb]

In what part of the country are you located? I have a rather large system I built for outdoors that I no longer use, and I would love to find a good home for it.

[RJP]

Northern New Jersey

[SAguitar]

Just down the road apiece!