The problem that I see with this experiment is that not everybody used speakers/earphones capable of make the difference distinguishable. With some speakers or earphones you can hear the difference, but with others you can't. I tried using my cheap speakers and I couldn't hear any difference. Then I tried with my high-quality earphones and the difference was pretty clear. As an experiment I think is great, but the speaker/earphone quality is an important factor that shouldn't be ignored. Of course, in an online experiment it's not really possible to control this.