Let's compare the specs of Pioneer's AX3 and harman/kardon's 330:
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Pioneer AX3
Power Output DIN 7x100W (1kHz, THD 1% and 6Ω
Power Output RMS (2 channel mode) 2x100W (20Hz - 20kHz, 0.09% and 6Ω
harman/kardon 330
Power output Seven-Channel 7x55 Watts per channel @ <0.07% THD, 20Hz 20kHz into 8Ω
Continuous Average Power2 channel mode): 2x65 Watts per channel, 20Hz 20kHz, @ <0.07% THD, both channels driven into 8Ω
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Firstly, look at the distortion figure. For the Pioneer it is 1%, whereas h/k's is 0.07%. In other words, h/k rate their receivers while reproducing a higher quality signal.
Secondly, Pioneer show their ultimate power rating at only 1kHz, rather than the whole audio spectrum as h/k do.
Thirdly, Pioneer use DIN specification to augment low watt ratings while running all seven channels. Note that in stereo the much more stringent (and standard) RMS rating is used, yet there is no change in power. This is a clue that the amp, whilst running all channels, may not be as powerful as initially indicated. h/k always use RMS.
Fourthly, Pioneer use 6Ω loads, rather than a more standard 8Ω as h/k do. The lower the speaker resistance, the higher the theoretical amplifier power.
Lastly, an amplifier supplies current to your speakers. It is this value that represents the true power of an amp. h/k traditionally make very powerful, high current, designs that drive speakers much better than their wattage ratings would suggest.
This kind of power manipulation is reprehensible. More so from Pioneer as the AX3 is ironically quite a powerful amp.
Hope this helps.
Russell