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a question

Old 05-10-2006, 04:59 PM
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a question

hello....

i'm new to the car audio wprld, i wanna ask what does (nominal power) on a speaker mean.
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Old 05-10-2006, 07:04 PM
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Originally Posted by sigfrid
hello....

i'm new to the car audio wprld, i wanna ask what does (nominal power) on a speaker mean.
RMS, Nominal, Or constant. I think the last one explains it the most.
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Old 05-10-2006, 07:17 PM
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and if the above is not laymans enough. it is the power that the speaker is able to handle constantly or musically.
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Old 05-19-2006, 11:15 AM
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Originally Posted by Justin LaRouche
and if the above is not laymans enough. it is the power that the speaker is able to handle constantly or musically.
This is actually contradictory.
There are no industry standard measurements for this. But there are 2 ways to measure power handling by speakers, or power output by amps:

RMS or nominal, average etc.
this refers to how much power a speaker can handle continuously.Generally there are 2 ways to measure this:
1: for individual speakers like subwoofer, midrange, and tweeters this defines the power of a single frequency sine wave applied to the speaker without burning it or destroying it physically. Tweeters are usually measured without a crossover so they will measure very low power handling. Keep in mind that there is very little power in music at the tweeter frequency ranges.
2: for full range speakers or 2-3 ways with crossover, this can be measured with noise that is filtered to have a frequency distribution similar to music. There is no standard definition of what this distribution is. Todays house and techno has very different disctributions than classic or jazz.

What this means is that if a set of component or coax speakers is rated at 100 watts RMS, then mostlikely the woofer can handle a 100watt, 1kHz sine wave, but the tweeter will fry instantly if given 100wats at 10kHz.

Peak, music, max etc.
This is an indication of the maximum peak power the speakers can handle when playing average music. These peaks are intermittant and do not last long. Again there is no standard way to measure it and obviously no definition of average music.

Again please no one take me to task on this as there are NO industry standards for speaker power handling!

In addition, power handling is not a measure of sound quality! Many company's low end 3-4 way coax speakers have a higher power handling rating than their high end quality sound speakers. On the other hand, companies that make high quality speakers such as Focal, MBQuart, DSL etc. usually rate their power handling accurately and you can compare low end to high end within a brand.

Last edited by zoomer; 05-19-2006 at 11:19 AM.
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Old 05-19-2006, 12:45 PM
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AVI rates their speakers power with pink noise!
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Old 05-19-2006, 01:50 PM
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There are several standards used to rate speakers but few people know what they are and few companies use them or actually state that they used them....... most good power ratings state the continuous RMS power the amplifier is capable of delivering and the duration is 2 hours or more...

using pink noise (and not sine wave) is a pretty standard way to rate a speaker as it is somewhat representative of music in its power distrobution through the frequency range.

In fact a tweeter rated for 500 watts may only see 50 watts with pink noise and a 500 watt amp which is about what it would see if it was playing actual music..
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Old 05-19-2006, 01:59 PM
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Pink noise has power density described by a 1/f funcion. and therefore has equal power in each octave and is very usefull when using a real time analyser. It does not represent the power distribution of typical music.It may or may not be the best signal to measure speakers. Like I said, there is no uniformally accepted and used standard. So beware when comparing specs!
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Old 05-19-2006, 02:02 PM
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Originally Posted by Haunz

In fact a tweeter rated for 500 watts may only see 50 watts with pink noise and a 500 watt amp which is about what it would see if it was playing actual music..
Please show me a speaker that can really take 500 Watts, with a tweeter that can handle 50 watts! Pehaps pro PA systems, but certainly nothing that will fit in a car!
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Old 05-19-2006, 02:20 PM
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^ Ive seen car audio tweeters with 500 watts stamped on the package from a few different mainstream companies... the rating may have been bogus but that is a moot point, as it was just and example

(on a side note the bullet tweeters in my car can handle a 500watt amp )

perhaps you know of another test signal that is more representative of music other then pink ? why would it be usefull for RTA but not power ratings ?

you also might want to try a google search before you state that there are no standards used to rate speakers... because I know of several...

Last edited by Haunz; 05-19-2006 at 02:25 PM.
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Old 05-19-2006, 03:22 PM
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I grant you that I did not google speaker power handling tests. Speaker test standards exist, for frequency response in anechoic chambers, but you probably will agree with me that they are not used much in the car audio industry for power handling. It is a complex issue. Bottom line absolute power handling is probably not a spec that is important by itself and says nothing about efficency, distortion and maximum output. I am sure we both agree on the subject. What I am trying to get at is do not make a speaker purchase decision simply on power handling, especially if it is some cheap made in China speaker claiming 1000 watt handling that cost only $19.99! I have come accross to many people buyin speakers only because of their power handling! As for that tweeter: What was the crossover frequency? for how long? How much distortion? See what I mean? Think of a 100watt light bulb. How hot does it get? So hot that you cannot touch it and it will melt plastic and cause paper to catch fire. Now think of that small tweeter. Do you really think that it can dissipate 50 or 100 watts without melting? Where is the heatsink? How does the heat get from the voice coil to the air? Etc.

As for pink noise, it is a constant 1/f decrease in power versus frequency. So that the power in a given band, say between 100 and 200 hz (1 octave) is the same as between 1Khz and 2Khz (also 1 octave) This is to match RTAs that measure in 1 octave, or fraction of an octave bands. It can be used to test power ratings, and may be usefull if all speakers are tested the same way, But it does not match the frequency distribution of average music... if you can define average music, so even 2 speakers that measured the same would not necessarily handle real music the same way.
Have a good long weekend!

Last edited by zoomer; 05-19-2006 at 03:29 PM.
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