How much power do i need for a PA?

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ryan7585

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I need a PA and i've been shopping around, but i really dont know how much power i need to have the vocals carry over the instruments well.. i only need it for practice, cause most venues have PA's, but we play generally very loud.. what do you suggest?
 
Depends on how loud, and what speakers you have.

I have a 150W powered mixer we used for practice and it worked fine for volume with some large EV mains.

One option is to buy a power amp and mixer separately. That way if you need more power, you just change the amp. You can usually get good used 2000W amps for less than $400.

Ed
 
Not much!

I have some powerd jbl eons that I have used for years for my blues /rock band and they never let me down. i play small clubs and bars and wedding partys. I never really cranked them up , ever! not only that they are very light weight i can carry both of them at the same time if I have too. all you would need then is a small mixer with some effects. these speakers are dummy proof. mackie also has some killer sounding powered speakers that also work as killer monitors as well. JBLs are cheaper though!
 
i've always used a mixer/amp which definitely limits u in the long terrm but is easy to carry around - i think it was 700 watts per channel - plenty loud enough and that was playing loud as well.
 
Len75 said:
I have some powerd jbl eons that I have used for years for my blues /rock band and they never let me down. i play small clubs and bars and wedding partys. I never really cranked them up , ever! not only that they are very light weight i can carry both of them at the same time if I have too. all you would need then is a small mixer with some effects. these speakers are dummy proof. mackie also has some killer sounding powered speakers that also work as killer monitors as well. JBLs are cheaper though!
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They would never cut it for my band. Once you have 2 100 tube guitar heads, a 300W ampeg with 8 10's for bass and a huge cannon of a Ludwig drumset playing metal, your little eons would suffer dearly. That is if you wanted to hear the vocals at all.

A pair of SP2's and a 1200W amp minimum
 
I have a mackie 1400i. it puts out 300 amps on stereo per channel. If you play really loud i don think this amp would be enough to "clearly" hear the vocals over a drum set and guitar. I don't play loud...been there done that. We usually put a drum set in another room and the amps in the other.
I never beleived in the combo amp/mixers...personal choice.








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Nateneal1966 said:
I have a mackie 1400i. it puts out 300 amps
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Holy crap, you could weld with that much amperage.






















I think you meant watts. :D
 
If you had a 600 watt amp pushing 2-15's, you're only using 8 ohms (stereo). add 2 more 15's and you'd be using 4 ohms - 4 more and that's 2 ohms which will give you much more volume than 2-15's on a 1200 watt amp. Speakers have breaking points. Use more of them and the "stress" is on the amp. Most amps can push a 2 ohm load these days. I'd say keep the powered mixer and buy more speakers.
 
chris-from-ky said:
If you had a 600 watt amp pushing 2-15's, you're only using 8 ohms (stereo). add 2 more 15's and you'd be using 4 ohms - 4 more and that's 2 ohms which will give you much more volume than 2-15's on a 1200 watt amp. Speakers have breaking points. Use more of them and the "stress" is on the amp. Most amps can push a 2 ohm load these days. I'd say keep the powered mixer and buy more speakers.
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No, most amps claim to be able to power a 2 ohm load, most don't live up in real life. I have a brand new CS800, it can't reliably run a 4 ohm load when it's really being pushed. It'll run at 8 all day long though.
 
ryan7585 said:
I need a PA and i've been shopping around, but i really dont know how much power i need to have the vocals carry over the instruments well.. i only need it for practice, cause most venues have PA's, but we play generally very loud.. what do you suggest?
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We use just our monitoring system at rehearsal (200-watts per monitor, plus sidefills and etc).
 
HangDawg said:
No, most amps claim to be able to power a 2 ohm load, most don't live up in real life. I have a brand new CS800, it can't reliably run a 4 ohm load when it's really being pushed. It'll run at 8 all day long though.
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It's important to understand that impedance is affected by frequency, and that impedance ratings are usually given for a specific frequency. During playback of a fullrange audio signal into a 2ohm load, there will be instances where speaker impedance will drop well below 2 ohms. When driving multiple fullrange cabinets with a single amp at high power levels this could be a problem.

It's not as much of a problem for bi-amped or tri-amped systems since each amp is not driving a fullrange signal into a low impedance. I have a 3-way system with 2400watts/2ohm into the bottoms 1200watts/4ohm into the mids and 500watts/8ohm into the horns. It will run all day long at high SPL's without any trouble.

Dwain
 
my band uses a carvin powered board. very clean sound, built in effects if you want them, 4 seperate monitor mixes(300watts per monitor at 4ohms), 2 built in eq's, 16 channels.

very unique board, and plenty of power for rehersal or running stage mix live in a small club, heck maybe even a big club.
they are down to like a $1000 bucks right now.

i dont sell these so dont think i am advertising here, but i really love this board. i cant think of one that can compare to all the features/power, and you can crank it with no plroblems as long as you watch your meters,and clip lights of course. The nice thing is you dont have to crank it all the way, it has enough volume and clarity at medium settings.

peace
 
Ryan, if there is a place that rents PAs in your area, try renting a small system or two to see what they can do. This will give you an idea of how much juice you need. Then start shopping.

Also for practice in a small space, placing your speakers will make a big difference in how well you can hear it.

Here is a link to a thread by someone practicing in a garage, some problems they had, and some suggestions.https://homerecording.com/bbs/showthread.php?t=142117&highlight=speaker



Soundbyte said:
It's important to understand that impedance is affected by frequency, and that impedance ratings are usually given for a specific frequency. During playback of a fullrange audio signal into a 2ohm load, there will be instances where speaker impedance will drop well below 2 ohms. When driving multiple fullrange cabinets with a single amp at high power levels this could be a problem.
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Yes, but it's not a linear function. There will be peaks and dips across the range of the cabinet. Each driver in the cabinet has it's own curve where it goes above and below it's nominal impedance. The overall curve therefore has peaks and dips. The box design even makes a difference.

Soundbyte said:
It's not as much of a problem for bi-amped or tri-amped systems since each amp is not driving a fullrange signal into a low impedance. I have a 3-way system with 2400watts/2ohm into the bottoms 1200watts/4ohm into the mids and 500watts/8ohm into the horns. It will run all day long at high SPL's without any trouble.
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Each bandpass, lows, mids, and highs, will have points where the impedance drops below nominal. The actual power being put into that 2 ohm load is the issue. An amp might handle a 2 ohm load at half power all day, but start to choke at full power after awhile.
Biamping or triamping with an active crossover lets you use each amp and driver more efficiently, and generally with better sound quality vs. the passive xover, that's all. Sub amps work harder because they need to put out much more average power to balance with the mids and highs.

Your sub amp can handle two ohms all day long at full power because it can, not because it is only driving one bandpass. :)
 
<<Damn, you need 1200W for rehearsal? Do you have much hearing left?>>

that's what i was thinking! we use 400W for GIGS! and we play electric rock!

maybe instead of getting a huge-ass PA for vocals at rehearsal, and since you've already got a mixing board and (i'm assuming) mics.......maybe you should look at getting a headphone amp, some of harvey's "more me" headphones, and using headphones for rehearsal instead of monitors. or maybe invest in some IEMs instead.

it'll save your hearing AND allow you to hear everything (especially the vocals) much better. when you've got better monitoring, you play better. the $200 we spent on cans and a canamp was one of the best investments we made as a band.


cheers,
wade
 
mrface2112 said:
<<Damn, you need 1200W for rehearsal? Do you have much hearing left?>>

that's what i was thinking! we use 400W for GIGS! and we play electric rock!
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We currently use about 8k for the larger rooms. You can't tell me that you are micing a drum set with 400 watts. No way in hell.
 
HangDawg said:
We currently use about 8k for the larger rooms. You can't tell me that you are micing a drum set with 400 watts. No way in hell.
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LOL. I did a couple of shows last summer where it took 8k just to get the kick and vocals over the band.

I'm trying not to do shows that loud anymore. I was amazed.
 
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