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RMS power question


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My new JBL MRX 12's say 400W rms at 8 ohms. In the manual it reads the recommended power amplifier was 800-1600 watts at 8ohms. Another website I saw from Crown stated between 1.6 and 2.5 x the RMS power rating is the correct power for a given speaker. My question is this: We have a Carvin DCM2500, which is 500W per channel @ 8homs or bridged 2500w at 4 ohms. Should we be running these speakers in a chain and pushing all 2500w @ 4ohms into them for roughly 1250 w per speaker? The manual says up to 1600!!! We run them currently with 500w per side @ 8ohms and the amps don't clip, but we can turn them almost all the way up. Any help?

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If the search function was working, you would be able to find plenty of relevent info...

 

Andyway, first forwarning you that I am a bit on the conservative side as we operate a reconing shop as part of our service business and that I have seen plento of failures in my 30 years of doing this

 

My suggestion is somewhere between 1.0 and 2.0X the RMS rating of the speaker. The more experienced and careful you are then higher you may go. With the rapid and inexpensive increase in amplifier power over the last 10 years, I have seen a huge increase in speakers that were grossly overpowered, or powered too high to be able to survive an "accidental event" such as a dropped mic, uncontrolled feeedback (yes, even for a few seconds can damage things if the amp is big enough) etc.

 

My personal recommendation for the 12" MRX is somewhere between 400 & 600 watts RMS provided the box is high pass filtered at about 50-60Hz. I believe that's a 3" "differential drive" woofer.

 

No high pass filter and I would stick with 400 watts per box.

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Thanks. We are running them at 500w per speaker right now, so that seems like a happey medium between 4-600. They sound crystal clear. It's really the first set of high end speakers we've bought and you can really tell the difference. It scared me when the manual said 800-1600 watts. If I interpreted you correctly, for the application we use it, which is small bars running sound ourselves while playing, we are better off to not have that much power running through them to take our amatuer-ness into account for accidents and what not. If we purchased say a feedback supression rack unit and/or a limiter would it make it safer to put more power into them? Thanks for the input.

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I roll the dice more often and use twice the power, but I set other things conservative and a little limiting comes in handy too...I haven't blown a

 

 

care to discuss the "other things" cause I'm pretty new at this, and I'm trying to sponge in all the info I can. What do you set conservatively? Also, another line of thinking I let myself travel down was that if we did have 1250w going to each speaker, we could turn the amp down to about halfway or so and have 6-800w with the amp not turned up as far. Would that be working the amp less hard than running it at 500w and turning it up almost all the way? Is that what headroom is? I would literally never need all 1250 running full blast into these speakers. Before I did that I'd buy more speakers and another power amp. As of now, safe and reliable is the way i'm going to go. I'm just looking at all possible options. Thanks for the input.

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Turningthe attenuators down by 50% does NOT reduce the amp's output power at all. It decreases the sensitivity, which ,means that the console will need to deliver +6dB of additional drive signal before reaching full power.

 

Keep to the 500 watts, until you get a lot more experience avoid the temptation of more power. It';s like driving a car, an inexperienced driver will generally get into more trouble with a muscle car until his experience increases. Some folks never learn either. Those are who I make my real re-cone money from as they tend to bring in truck loads of expensive drivers after an "accident". My last big recone job was for more that $1,500!!!

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