peak power vs RMS

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Jan 31, 2011 | 04:31 PM

octaneforce

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Laughing Gas

Joined: Mar 2009

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From: long island

peak power vs RMS

whats the difference between peak power and RMS? im on the best buy website looking at head units, and alot of them say 50w, but some have 17w rms, and others 22rms.

also, i am looking for a basic head unit without any fancy satiellite radio or touch screens or anything like that. i want to spend somewhere in the range of 150 dollars. if anybody wants to make a suggestion, please do. my truck is in my sig. thanks

Jan 31, 2011 | 09:06 PM

V10man

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From: Mesa

Check out crutchfield.com. Lots of good info there. In a nutshell: Peak is just that, the highest wattage it can produce. RMS is the wattage where there is no distortion. Anything beyond that distortion occurs.

I like Pioneer units. Get one with a USB port so you can play all your downloaded songs.

Jan 31, 2011 | 09:50 PM

octaneforce

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Laughing Gas

Joined: Mar 2009

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From: long island

distortion is the reason i want to replace my current unit. whenever i try to crank a song moderately loud, i get a fair amount of distortion. i also agree with going for pioneer. i was looking at pioneers and alpines with the usb/accesory port.

Jan 31, 2011 | 09:57 PM

octaneforce

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Laughing Gas

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From: long island

Kenwood KDC-HD545U CD receiver at Crutchfield.com

i just found this on that website. it seems to be exactly what im looking for, although i didnt give any thought to a kenwood unit. it even comes with all the harness kits and trim.

Feb 1, 2011 | 03:04 AM

fz1dave

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Joined: Oct 2010

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From: NW IN.

Quote:

Originally Posted by octaneforce

whenever i try to crank a song moderately loud, i get a fair amount of distortion.

That's sounds more like a speaker issue. What kind of speakers do you have in there? Are you running an amp?

Feb 1, 2011 | 10:49 AM

AudioNutz

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Quote:

Originally Posted by V10man

...RMS is the wattage where there is no distortion. Anything beyond that distortion occurs...

Proof that you can't believe everything that you read in the internet.

The RMS value is the square root of the arithmetic mean (average) of the squares of the original values (or the square of the function that defines the continuous waveform).

NOTHING to do with distortion.

For purchasing sake... Never look at peak values, always look at RMS, and try to look for a rating that includes full range frequency response with all channels driven.

For example, car audio manufacturers could typically get away with a peak rating measured where only a single channel of a 4-ch device is driven, only measuring 1khz frequency band, and at 50% distortion. If you are diverting all of your power to a single channel, to get that peak, you're certainly not going to reach that if all 4 channels are driven. Same with the frequency of the measurement.

Also, you will NOT hear a difference between 17 and 22 watts RMS. The human ear is simply not sensitive enough to tell less than a 3db change, and you would have to double the wattage (34w) to get a 3db change.

Feb 1, 2011 | 11:12 AM

octaneforce

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Laughing Gas

Joined: Mar 2009

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From: long island

thanks for all the info. my speakers are new and were fairly good sets, however i do not remember the brand of them. max wattage really seems like false advertisement with these head units when compared to rms. (especially since nobody is going to drive just a single channel with their stereo) il just have to make sure the head units im looking at have good rms.