We cannot generalize ONE experience as a rule for all system...
I myself own a powerful Sansui Alpha 607i to drive my picky headphone from the headphone out ...It is my reference system over my small speakers so good they are now ...
I never experienced a mid range blooming so beautiful and realist in my life with anything i heard with speakers and headphones save with the K340 well done and optimized because it is the most hard to figure out headphones there is , being the more complex with his dual chambers, and his hybridration crossover point for his 2 different cells, electrostatic and dynamic , and 5 tuned passive resonators ... and with a complex demand and hard to drive sensitivity of 87 dB/mW and 2 cells of 400 OHMS impedance each ...
I tried to upgrade the S.S. Sansui with one of the best regarded tubes technology in the world ... I returned it the same day ...This blooming of the mid range was lacking and the out of the head headphone soundfield so characteristic of my optimized K340 was no more there ...
Could i say the reverse opinion of ghdprentice and pretend that my experience is a universal fact and a future rule for all ears, all systems ? No ...I must be as cautious as ghdprentice here ...
Even if i believe completely the testimony of ghdprentice , i had the reverse experience ... No design rule alone , it must be implemented acoustically, electrically and mechanically , and be synergetical with the other components ...