rms numbers

[Sam524 10+ year member]

tried searching for an answer but couldn't find it. but yea what do the different rms numbers/ohms mean? i always see so many numbers and notso sure what some of em mean. like if when i look for how much power i want two subs to put out, i dunno which numbers i should really pay most attention to

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[JimJ 5,000+ posts]

http://www.bcae1.com

RMS - Root Mean Square voltage, to grossly oversimplify, the "average" voltage that the amp outputs. Technically "RMS power" is an inaccurate term, but nobody cares //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Ohms - measurement of electrical resistance, or impedance in an AC circuit. Basically the opposition to current flow, to again use a gross oversimplification...

 

[stones 10+ year member]

RMS is the actual power output of an amp and the actual power handling of a speaker, peak is just for show basically.

as for OHMs read this

http://www.caraudio.com/vb/showthread.php?p=1044638#post1044638

 

[JimJ 5,000+ posts]

Once again...

I > Chuck Norris //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[VereChronicus 10+ year member]

To make things even harder to understand, there is no actual standard. There are standards that companies can choose to adhere to if they choose, but there is no law to force them to do so. This simply means that the box can say that the subs are 4000w rms per coil and in reality they may only handle 475w rms. Max power handling for speakers is just an indicator of what they can handle via their weakest link. Again this number can be fudged by the manufacturer. Reputable brands most often stick to a more realistic standard: CEA. The CEA 2006 standard is great for subwoofers, but it has not stayed for amplifiers. It has changed 3 times since its inception as far as amplifier output power rms rating with different distortion levels. Still not sure there myself, so compliance has got to be obviously hard for manufacturers. If you want a quick, easy way to think about OHMS: blocks of resistance. Each speaker has blocks of resistance.....how many is its OHMS. Each amplifier is made to make full rated rms power output into a given block of OHMS. If you want an amp that is rated to produce 400w rms into 4ohms, then you need to get a sub or subs that equal 4ohms by wiring it or them one way or another.