I recently massively upgraded my stereo system from the Aiwa Home-Theater-in-a-Box NSX-MT720 to Harman Kardon's AVR-330 receiver. To put in perspective the differences in the systems (and hence why the old center channel is so deficient) here is a look at their attributes. You might notice that the Aiwa system can output 80 watts for the main speakers, whereas the Harman Kardon is rated at 55 watts. Let me dispell some common misconceptions about wattage and audio systems.

All Watts are not created Equal

The advertised wattage of a given system is subject to MASSIVE exaggeration by manufacturers. Well, actually, they don't exaggerate. They give the performance of their product in an ultra-narrow set of conditions that are never observed in the real world (unless you get a kick out of 1 kHz sine waves). Honest, high-quality manufacturers post the wattage their amplifier produces across the full bandwidth of 20 to 20,000 Hz. They also give the ratings for when all channels are being driven simultaneously. An honest company gives you the wattages of their machine when it is playing actual sound across all the outputs. Companies inflate their ratings by cutting down to just 1 frequency, 1kHz and just 1 channel driven. Obviously then the amplifier only has to produce one frequency for one speaker it is going to be much louder.

Another common trick is not post distortion ratings. Sure, Logitech’s 5.1 system might pump out 500 watts, but what kind of distortion is it producing? Guess what? They never tell you! Often times the wattage of a high quality amplifier will be underrated so that the performance is reported at a volume where the sound is crystal clear. Those same high performance amps could run circles around the poor quality ones in the category of sheer volume if distortion, bandwidth and channels driven didn't matter.

In case you wanted to know more:

• Secrets of Amplifier and Speaker Power Requirements Revealed
• Product Managing Receiver Platforms & Power Ratings
• Watts Up with Amplifier Power?

Aiwa NSX-MT720 vs Harman Kardon AVR-330

click to enlarge	NSX-MT720	AVR-330
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Some Quick Spec Comparisons

I suppose these are a bit overkill; you get the point – the AVR-330 is much better. Considering what I paid for the Aiwa and that I was in 10th grade at the time, it served me well. It met an untimely demise when my bike fell on top of it (in a trailer) driving home for summer break. When i was powering the center channel with the Aiwa, all the speakers sounded equivalent, since they were limited by the quality of the amplifier. Now they are all being driven by the Harman, and as you can see in the picture, the main speakers are far more capable than the old center. The main speakers sound like new life was breathed into them with a better amplifier, but the center channel hardly improved at all. As it stands, the center channel is annoying to listen to, hence ready to be replaced. For some professional benchmarking results of the performance figures for the AVR-330, check out this: <review> | <lab>