The HE-300 is terrible. It is thin, tinny, and full of distortion. I will never recommend a headphone with those qualities.
Here are the charts:
The Q701 has a smoother and more flat frequency response. It has more accurate 30 Hz square wave response seen as less of a severe slope as seen on the HE-300. The 300 Hz square wave on the Q701 is also much closer to an actual square wave. The HE-300 is all over the place. The HE-300 has more ring in the impulse response. That is just what the charts tell us. The sound supports the graphs and the HE-300 remains a poor choice for anyone looking for a serious, accurate, and enjoyable headphone.
The audiophiles over at Headroom agree. They give the HE-300 which I bet if you asked them in person would be generous. While the AKG Q701 receives 5 stars and has perfect reviews. My one and only gripe about the AKG Q701 is that the headband is a tad uncomfortable, but a little added foam fixes that in a hurry.
Edited by NA Blur - 12/12/12 at 3:30pm