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<blockquote data-quote="thch" data-source="post: 3528444" data-attributes="member: 562032">DMM -- measure voltage, V^2 / R, assumes fixed R and clean signalClamp -- measures current, I^2 * R, assumes fixed R and clean signalDMM+Clamp -- measures voltage and current.&nbsp; V * I.&nbsp; can be low as the speaker&#039;s actual impedance may be higher then the nominal&nbsp; R = V / I.&nbsp; Also assumes a clean signalOScope -- measures voltage, V^2 / R, assumes fixed R, signal should be cleanOscope + Clamp -- Measures voltage and current.&nbsp; can be low.&nbsp; Signal should be cleanOscope + Current Transducer -- Measures waveforms of both voltage and current, can calculate actual power (defined by used energy), can give low results as per above, but gives the most accurate &quot;actual&quot; results.There are many things you can determine -- maximum output power, actual output power (with speaker), speaker impedance.Simple testing may not give the same number as on the box -- the test conditions may be different.&nbsp; in the end, there is too much emphasis placed on such measurements.(side note, anyone ever try one of theose &quot;kill-a-watt&quot; meters, they should be able to give power, apparent power, and power factor, as well as volts and ampres for 60hz)</blockquote>

[QUOTE="thch, post: 3528444, member: 562032"] DMM -- measure voltage, V^2 / R, assumes fixed R and clean signal Clamp -- measures current, I^2 * R, assumes fixed R and clean signal DMM+Clamp -- measures voltage and current. V * I. can be low as the speaker's actual impedance may be higher then the nominal R = V / I. Also assumes a clean signal OScope -- measures voltage, V^2 / R, assumes fixed R, signal should be clean Oscope + Clamp -- Measures voltage and current. can be low. Signal should be clean Oscope + Current Transducer -- Measures waveforms of both voltage and current, can calculate actual power (defined by used energy), can give low results as per above, but gives the most accurate "actual" results. There are many things you can determine -- maximum output power, actual output power (with speaker), speaker impedance. Simple testing may not give the same number as on the box -- the test conditions may be different. in the end, there is too much emphasis placed on such measurements. (side note, anyone ever try one of theose "kill-a-watt" meters, they should be able to give power, apparent power, and power factor, as well as volts and ampres for 60hz) [/QUOTE]

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