Musician Gear & Tech Discussion

I have been looking into adding more power to our present system to better accommodate the larger outdoor venues we've been getting.

As I read and research I keep coming across references to amplifier output needing to be roughly double that of the speakers capacity.

I know this is an over simplification but I'm a simple kind of guy ya know.

So the speakers I have and would like to obtain more of are a three way 4 ohm that handle 800w cont. 1600 program and peak 3200.

The manufacturer recommends 450 - 900 watts of amplification for each of these speakers.

The amplifier I am looking at runs 750 watts at 4 ohms.
Sounds sufficient by the manufactures recommendation.

Any thoughts on this process??

The speakers are only one aspect of SPL. Which speakers? Are you using subs? Only vocals through the mains, or the entire band?


750 watts into 4 ohms is really not that much power. Doubling the wattage of a system only results in a 3 dB increase in SPL.

My current speakers being utilized as main are Carvin 2153's
The bass amp feed and the drum mics ( except for the overheads ) feed into a separate PA and run the bass cabs. No subs.
The rest of the band plus a feed from the bass / drum PA are run by the main PA that has four 400 watt amps (monitors x 2) and L / R mains.
The pre EQ main out is what I would feed into the additional amplifier of 750 watts per side to two additional 2153's

Confusing ? LOL

My current speakers being utilized as main are Carvin 2153's
The bass amp feed and the drum mics ( except for the overheads ) feed into a separate PA and run the bass cabs. No subs.
The rest of the band plus a feed from the bass / drum PA are run by the main PA that has four 400 watt amps (monitors x 2) and L / R mains.
The pre EQ main out is what I would feed into the additional amplifier of 750 watts per side to two additional 2153's

Confusing ? LOL

When you say "bass cabs", are you talking about the 2153 bass drivers? You said you don't have subs. Are you bi-amping the 2153's?

When you say "separate PA", do you mean a separate mixer, or a completely separate PA system?

Seems like kind of a complicated system. You're planning to run (4) 2153's? The 2153's are nominally rated at 4 ohms, and bi-amp at 8 ohms. A 750 watt/4 ohm amp will do OK with two of those speakers, but I think you'll get more punch if you get a pair of subs and a Driverack. Put your bass and kick through the subs, and everything else through the 2153's.


You aren't going to gain much SPL by doubling up on the 2153's. Chances are that coupling will actually cancel out some of the SPL and result in less SPL. You might try renting a couple of subs and running them off an aux feed. Just route the kick and bass through the aux feed to the subs. The HF drivers in the 2153's aren't very robust - I wouldn't be hitting them with too much juice.



The Driverack I would suggest is this one:


http://www.dbxpro.com/PA+/index.php

Thanks for the input.
It's difficult and wordy for me to describe our set up.

Our bass / drum PA is an older Sunn 450 watt powered mixer.
The bass cabs are one double 15" cab on stage left, and a single 15" cab on the right, with the bass players amp.
The Sunn runs just the two bass cabs.
The bass guitar has a cab voiced feed into the Sunn.
The drum mics feed into the Sunn.
The monitor signal off the Sunn ( bass guitar, kick, toms, and snare) feeds channel #1 of the Carvin RX1200 PA. (drives the mains)
My amp cab voiced out signal ( channel #3 ) as well as Rays ( channel #2 ) go into the Carvin
The three vocal mics (channels #10-11-12 ) and the two overhead condensers (channels #5 & 6) go into the Carvin PA
The RX1200 PA operates the two 2153s one right, one left, as mains.
The intent is to run the auxiliary main signal off the RX1200 into a separate EQ and amp in order to push two more mains.
( the auxiliary main out puts L/R XLR are pre EQ )
The current mains out put is 400 watts per side L / R
The additional amp / speakers would bump that to an additional 750 per side L / R.

To summarize main speaker out put:
I currently have two 2153's L / R being run by my powered mixer at 400 watts each.
I want to add two more 2153's run by an added amp that will supply 750 watts to each of the new speakers. ( a two channel amp )

LOL
This would be a lot easier if we could walk out to the shop together.

Actually, that Carvin only puts out 300 watts at 4 ohms.

http://www.carvin.co.uk/products/mixer. ... ber=RX1200



If that system works for you, fine. It just seems like a lot of un-needed gear when you have a 12 input mixer. You could simplify things greatly (and get more power to the drivers) if you just ran everything into the Carvin, ran the mains signal to a larger amp for the mains and the sub outputs to another amp for the bass and kick.


To each his own, though. Your original idea of getting another amp to run a second set of 2153's would work - I just think there are better (and simpler) ways to achieve your goal. If you got a pair of powered subs and just put the bass and kick through them, people would feel the boom in the base of their spines.

Ah yes. You are correct 300 w @ 4 ohm. I had been reading the specs on one of their newer boards and confused my info.

And your suggestion is actually my objective.
But being only able to afford the equipment piecemeal, I am attempting to utilize what I have on hand while gradually acquiring the other equipment.

I would also like to eventually get a larger mixer (perhaps 32 channels) and use separate rack gear. That is one reason I have not already purchased powered subs. That and being a logistics fanatic I like to have back up systems redundified.

I appreciate your input 90dB .
Talking with knowledgeable people helps me map this stuff out in my widdle bwain.
Will also save me money and hassle in he long run.