# Use Gain to Turn Down RMS Wattage?



## bhammer (Dec 9, 2011)

Is it safe or effective to use the amps gain to keep from over driving a speaker? I'd like to use the two extra channels on an NX4 to drive one single 3.5" center channel speaker. The issue is, the NX4 is 100 watts and there are no speakers that I can find, in my budget ($100), that are rated for this.


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## 02bluesuperroo (Oct 31, 2006)

Yes, this is the proper way to do it and will be effective.


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## bhammer (Dec 9, 2011)

Thank you. Is there a formula I am looking for, for the proper AC voltage output of the amp?


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## t3sn4f2 (Jan 3, 2007)

There's no way, music is extremely dynamic and much easier on a speaker than the sine wave you will set max gain to. And in order to do what you want, you will have to set the head unit volume to a max point and never pass that. So when you get a very dynamic track or a low recording level, it then won't get as loud as your modern tracks. And when you turn it up past that determine point to compensate, you will loss that mark where you "set gain to x wattage to protect the driver". And you won't know where that new point is since you don't know where the song peaks. 

And as the voice coil starts to heat up it becomes more resistive which causes the amp to put out less power, by as much as half the power. which throws off your calculation there too.

Pointless. Look how home receivers leave almost 50% of the volume scale without ever hardly being used, it's there for the reasons above and is needed. 

Best thing you can do is listen for when the speaker doesn't get any louder and starts to distort, then turn it down a bit.


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## sqshoestring (Jun 19, 2007)

Maybe like this?

Amp Tuning Voltage Chart - SMD Forum


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## ZAKOH (Nov 26, 2010)

To begin with, it's been pretty much confirmed that the NX4 does not do the rated power. With 12-13v, you'll probably see 60watts RMS at best. Next, why worry about RMS wattage? Do you play synthetic tones on your speakers the whole time and at full volume? Probably not. 

My tweeter amplifier is probably good for 80-100watts RMS. No problems so far. The actual musical power at the high frequencies is pretty low.


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## [email protected] (Jan 3, 2012)

Well its not like the power output from any amp is flat across the whole frequency range. Just turn the amp to the point just before clipping, and control it with the HU. Just because 4 ohm speakers are seeing 5vAC-RMS doesnt mean anything, because the impedance could be all over the place. Dont think so deeply into it.


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## sqshoestring (Jun 19, 2007)

If you are playing some bass into it, you can measure xmax to get an idea of its limits.


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