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Originally Posted by coryj hi people first time i have asked for help .i have two 15 inch rcf j bins 400 watts each 1 600 watt sub running behringer 2500 amp just perchsed no name amp 900 by 900 watt amp in 8 oms dont really know watt i am doing looking for clearer louder sound money is aproblem  http://www.talkbass.com/forum/images/smilies/nono.gif |
Let me see if I follow. You have 2 15" mains - 400W each. I'm assuming 8 ohms apiece. You also have a 600W sub, which I'm assuming is 4 ohms, although I might be wrong there.
You're trying to run it with a 2500W Behr power amp (IMHO has less punch than its 1500W QSC counterpart), and a no name 900W amp (is it Nady by any chance)?
And the problem is that you're not getting a loud, clear sound?
Here's how I imagine you're running things - correct me if I'm wrong. Each main speaker is connected to a channel of the Behr. The sub is connected to the 900W amp (hopefully it's bridged, but we'll see).
OK, first problem. When running 8 ohms per channel, the Behr provides a whopping 450W per channel. Your speakers are rated for 400W, which is fine, but Behringer traditionally doesn't handle its top end very well, so if you were running 200W speakers, you'd probably be fine. How to solve this problem? Bridge the sucker and run the mains in parallel (plug one speaker into the other). You'll have 2400W at your disposal (4 ohms) pushing only 800W between your two speakers. Be careful and consult your amp's manual to make sure you're doing it correctly, but that should give you more than enough power.
That having been said, I'm running 2 500W 15" mains and 2 4x12" mains off of the QSC RMX1450. One channel is running probably 450W at 4ohms (225W each speaker), and the other channel is running 700W at 2ohms. Plenty loud for any situation I've run into short of outdoors. I think the difference is a quality amp.
Now, on your 900W amp, you're likely not getting the thump you want from your 600W sub and thinking, "What the heck? I have more than enough power!" For the sake of argument, I'll assume you're using the Nady XA-900 Pro Stereo Power Amp, but other brands' specs should be relatively similar.
If your subwoofer is 600W @ 8 ohms, then you're really in trouble, because this STEREO amp puts out only 200W per channel at 8 ohms. Even if your sub is 4 ohms, you're still only getting 300W. EVEN IF YOU BRIDGE THE AMP, you're only getting 675W at 4 ohms, which means you're hitting the top of the sub when the (cheap) amp is running full tilt. Why is this particular amp called "900 watts"? Because they lie.
I just did some research to guess your subwoofer... 600W is a curious rating. PLEASE tell me that your sub isn't a Nady 15. If it is, brother, the best advice I can give you is to quit wasting your time there. Sell that sucker, go to
www.musicsupplycenter.com and pick up a Legion Sound sub. About the same price, but better quality.
Send me more specifics with some of your gear, including maybe some links to some of the stuff I'm not familiar with. Your RCF speakers seem to be budget line to me, but I'm not very familiar with them.
I can totally understand the desire for an entire PA on a budget. But don't do it at the expense of quality components, or you're just throwing money away.
Good luck, and let me know if I can be of any more help.
