Originally Posted by SpeakerPower
Unfortunately, the slideshow was put together by my co-presenter Scott Leslie so I don't have it.
Regarding the bottom line on the iNuke 12000, buckaman measured the maximum voltage at 103V, just a few more than I measured before the last return to the factory. So even though the knob now lets you set it for a higher limit, the voltage delivered does not match it and is insufficient to meet spec.
I would also like to reinforce what others said above; power is NOT calculated from peak voltage, but from RMS voltage. The only time peak equals RMS is for a square wave and hopefully that is not what we are listening to. There is no such thing as "peak" or "instantaneous" power, regardless of what marketing people say. Meaningful terms are Burst power for a defined but limited time and Continuous power.
My guess is you are saying the right things, but I feel there might be some things missing here for the average reader.
I would like to reinforce that what is being stated is only correct in the context of measuring loud speaker amplifiers. Power is volts * amps. Therefore, by definition is "instantaneous" since there is no inference of time. Secondarily there such a thing the call "peak power"; it is the maximum instantaneous power delivered within a measured duration. It doesn't mater if it is 1 femto second or 1 year. It is a very important specification when design power stages for ANY electronics.
So when the markers use the term "peak" or "instantaneous power", they may not be telling a fib because they may be "technically correct". Put it this way, if somebody asked me "did you brush your teeth", I could say yes since I could have done it last year and be "technically correct". The problem with "technically correctness" is that is is often misapplied for the sake of gain. Again if somebody asked me "did you brush your teeth today", I could say yes. But what if I only spent 3 seconds doing it? Again, what I said is "technically correct".
Secondarily, I really get what industry is trying to do, but I feel that the audio industry is still trying to invent "terms". This goes to constantly reading/hearing the term RMS watts. I mean a professor or person with reasonable experience might understand what you are implying...but I know I would be thinking "does this person know what they are really talking about". As a clarification, (Vrms)^2/R or Vrms*Irms (for resistive loads) is AVERAGE power; this is the correct definition. So to simplify, "burst power" and "continuous power" are both not correct enough either since it is not complete. It should be "continuous maximum average power" and "time limited maximum average power" if we want to clear on what is being measured. Even with that, the definitions stated will still allow a degree a specmanship by marketers that will result in disingenuous data which will negatively impact the consumer. I think to further clarify this the measurement cycle should account for several frequencies (e.g. 1 Hz to 20kHz) including sine AND square (we don't listen to this..but we don't listen to pure tones either). But again, this is looking for an absolute "truth" which isn't correct either.
I think it comes down to this, does the amplifier reproduce the desired input within a defined level of distortion? I personally think this is ALL that matters. How to get to this is the trick though. I mean the THX spec gives 85 dB + 20 dB headroom. So why not define the reference to be 0.01% distortion and 0.1% for the +20 dB. Play back "several" sound tracks which could be considered "punishing" for various reasons (e.g. high average or high peaks or both) into resistive loads (8, 4, 2, 1..etc). Once we know this we know the correct gain level for that amplifier and thus correct power. This means if we desire the THX spec, by very simple math we can know if the amplifier we chose will meet our needs. The only bad part of this method is it would require the amplifier industry to "agree" on the test files which would NEVER happen because that makes it HARDER to turn a profit and also pushes industry more towards being a true commodity which will reduce competition. Furthermore I'm not sure it is fair either because movies like edge of tomorrow are outlying cases.
Don't get me wrong. I'm glad people are starting to get a bit more serious on this. I wish some of the same effort was done for the magnetics industry (these guys make politicians and lawyers look honest). Thanks again for doing what you are doing.