Amplifier Specs

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#1 cotrunder

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Posted 28 May 2006 - 09:06 AM

I was wondering... Are the power measurements taken according to EIA or FTC standards available for Crown Amplifiers (precisely i am interested in Xs, Xls and Xti)?
If not, why? If yes, where?

Thank you.

#2 DGlass



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Posted 30 May 2006 - 02:24 PM

There are two standards that make it easier to compare amplifier output ratings the FTC and EIA ratings standards.
The FTC standard was established by the Federal Trade Commission and requires that a manufacturer’s stated power ratings must meet the advertised frequency range (usually 20 Hz to 20 kHz) at the rated THD (Total Harmonic Distortion) with both channels driven.
The EIA rating, established by The Electronic Industries Association, is the power output of a single channel driven at typically 1 kHz with 1% THD clipping. The EIA standard will typically be 10 to 20% higher than the FTC ratings.
We go one step further than the EIA ratings and drive both channels as we feel the fairest, most honest, and most revealing rating method is the obvious one: to specify power with all channels fully driven, as this is a more real world scenario. When fewer channels are being tested, the more power the ones that aren’t being used can deliver. This can artificially increase the apparent power output. By testing with both channels driven we are decreasing the standard 10-20% difference of one channel driven.
What does a 10-20% power difference mean in reality? For the average person to hear a difference in loudness/level, you would need to double the power to the speakers. You can hear the difference between 200 watts and 400 watts, a 3 dB increase or doubling of power, but you won’t hear a difference between 200 watts and 240 watts as small difference in output power are not discernable to the human ear.
To put it in a nut shell we basically provide a more conservative power spec of the EIA standard because we test with both channels driven during our tests not just one.
Since the differences between the two standards are really minimal, when you look at it, the more important questions should be things like amplifier features and reliability. smile.gif