Understanding pioneer direct energy power and others..what's inside ?

An amps power supply will put out a certain (fixed) voltage to the output devices. But as power needs increase the power supply is not designed to drive all channels to rated power. The rating should state (somewhere) that the tested the receiver with only one channel being driven. And it's tested into an 8ohm dummy load, and 8 ohm speakers are not fixed 8ohm loads; their reactance varies over frequency.

If your receiver does not put out enough power, you can -
* Consider adding an external amp(s) if your receiver has pre amp outputs
* Get more efficient speakers
* Move close to your speakers
* Get a higher powered receiver (just remember you need double the power for a 3Db gain, and as you have pointed out, power ratings can be misleading)

If you love that HK so much, consider getting one, I guess. But the Elite 91 should be a pretty strong receiver.

If by Db level, do you mean what's shown on the volume display ? It's likely uncalibrated, which makes it meaningless.

The best you can do is to play the same song over both systems, and crank them up to just below the point where you can hear distortion. Measure one of the speakers with an SPL meter from the same distance.

Even that won't tell you everything unless you and your friend have the same speakers.

You can't reliably compare amp power using the methods you are using. There's a lot of variables - you and your friend have different rooms, different speakers (I think,) etc.

I would not place too much stock in what number is showing on the display unless you know they are calibrated.

An SPL meter is a more reliable way to measure output.

sigh....the "dB" level displayed means NOTHING, as has already been pointed out twice. Your methods are NOT a valid comparison.

The number and type of power transistors determine it's maximum power. They could drop a power supply in the receiver capable of driving them to their limit. But they generally don't do that.

The most likely limiting factor is the power supply. As I mentioned above, it clearly can't drive every channel to the rated power. When they say an amp is 100x7 or whatever, they often mean that any given channel can output 100 watts into 8ohms (at whatever the stated bandwidth is.) Confusingly the receiver cannot output 700 watts. Not even close in many cases. Blame the FCC for their weak rules.

The Harmon Kardon may come closer to being able to drive all channels at the rated power. I have not looked at the specs, but they may even test with all channels driven. Another factor is the ability to drive lower impendence loads. Some amps can double their power as the impedence drops in half. Most can't. Harmon Kardon claims high current capability, which is just a fancy way of saying their amp section performs better than "average" into lower impedence loads. Which may be why people claim an HK rated at 30 watts can equal another receiver rated at 70 watts (although I have never seen these claims proved.)

p.s. Audioholics.com has some excellent articles on power ratings

New or old should have nothing to do with it. They make crappy new grear and great old gear, don't they ?

As for lowering the sound quality, I can't say. But when Yamaha went from the 659 to the 661 (if memory serves me right,) they dropped some power while adding more HDMI functionality, apparently to keep it at the same price point. The 661 was lighter which means they probably dropped power by putting in a smaller power supply transformer.

It seems reasonable to expect a receiver to cost more if they add more parts to it such as HDMI chips and video processors. To keep it at the same price point, something's got to go, such as output power.

I don't know what you mean by 'when will the new gear surpass the old'. There's no reason to assume a 2008 receiver is going to be better than a 2007 receiver just because it came out in 2008 or vice versa. Not to mention the fact sound quality is subjective.

If you have a lot of jack, look to a manufactuer's flagship model. They should use some of the best designs and components in those. I was reading the review over at Audioholics on the Z9 and they measured the distortion coming off the pre out jacks. It was ruler flat and had almost no distortion. If the advance of technology can improve sound quality, I would expect a flagship model to use techniques or parts that were not available last year.

I would like to see more receivers using class D amplifiers. The reason being that I think they can put more power into the receivers for the same price point once they perfect a mass market design. Class D based receivers should be more efficient, so they can cut down on the size of the transformer (an expensive part.)

I believe they should be able to create great sounding receivers with high power at an affordable price once they embrace the technology.

piquit....sounds like you're partial to one brand over another. Nothing wrong with that. I have no evidence that suggests one brand's quality will go down, or another's will go up.

As far as differences in amp design, there are a few criteria I go by. The last of those is the manufacturer's ratings. How the different amp types make their power is of little interest to me. Personally, I look at power supplies (I prefer Toroidal) and type to see if it will suit my needs. Efficiency of your speakers should have a "bearing". As others point out, there's no relevance between where the volume knob is and what kind of power they produce. Also, as others point out, use an SPL meter to find out what sound at what volume...even that won't tell you anything definitive.

Just remember, wattage means very little. Old vs new? I don't know that there's anything definitive that can be said there, either.

Damage to speakers comes in the way of when an AVR or amp clips. That's quite different than having "too much wattage".

But, if you're HK loyal, stick with them. If you're Yamaha loyal, same deal.

Don't discount Pioneer, Denon, Marantz or any of the others, though. As, they all make good gear.