That is really very interesting. I did talk this over with an associate of mine, who has been around audio for many years and who worked for my late boss, and his response was rather the same as mine. We both were perplexed at how a speaker that says its minimum wattage is 10W can be powered very well at all at a quarter of a watt. With that amount of wattage, you would only be listening to the tweeter, as the bass driver would not have enough wattage to hardly move, if move at all. The crossover's capacitors also require a certain amount of wattage to power up as well, and may also not be functioning very optimally. I would have to say, that at this low, barely functional wattage level, it would be near impossible to tell the difference between that denon receiver and the Sony, as the woofers would not be functioning hardly at all at a quarter of a watt. Not that I am a fan of Denon equipment, mind you. You would not be able to hear the difference in either harshness or richness or depth when comparing the units at that low wattage level when only the tweeters are functional. A more fair comparison, if you wanted to prove your point that expensive gear is not always the best in fidelity, would have been to compare a cheaper brand receiver (not a very low wattage boombox that can't drive your woofers) with that denon at equal output levels that drove your woofers of your speakers and the subwoofer coming from the receivers. You would then be able to judge at decent wattage how well the units were doing in terms of harshness, midrange, and bass frequency and then be able to make a very fair and interesting comparison between how the individual units sounded throughout the frequency range, not just at the upperend of the frequency range, which tells you nothing about the bass / midrange levels and their quality. I would suggest using a sub in this comparison, you could judge how clean and deep the units you were comparing went and how solid those frequencies were. I am not saying the Denon, would win out either. In fact, I have a suspicion you may find a receiver that was substantially cheaper that could very well beat it. I am not a fan of how Denon equipment sounds, especially the more recent Denon equipment. But I do not think that conducting a test where you are running less than a quarter watt into each speaker from a Sony boombox and a denon is a very fair test, when a person would only be hearing the tweeters. This of course brings us to a discussion about wattage amounts and more wattage vs less, damping factor etc. I personally have noticed a large amount of difference when comparing modified units that had less or a greater amount of wattage. The cone control and precision of movement is just far better. I do not think, though, that the technology was there for high wattage clean sounding units until recently.
