It is worth mentioning that my conclusion is based on the fact that I have extensively demoed (or owned,
in bold) the following headphones: AKG K812, K712, K702, K701,
Q701, K550, K271, K240 Studio, K77; Audio Technica ATH-M50X,
ATH-M50, ATH-M40X, ATH-M40fs; Beats by Dr. Dre Executive, Pro, Solo HD, Studio; Beyerdynamic T5 P,
DT 990 Premium 600 ohm, DT 990 Pro, DT 880 Premium 250 ohm,
DT 880 Pro, DT 860, DT 770 Pro-80; Bose Quietcomfort 15, Quietcomfort 3, Quietcomfort 2, AE2;
Creative EPH-630; Denon AH-D7100, AH-D600, AH-D340; Etymotic ER-6; Grado PS500, Grado GS1000, RS1i, RS 1, RS 2i, RS 2, SR325is, SR325i,
SR225i, SR225, SR125i, SR125, SR80i, SR80, SR60i, SR60, iGrado;
Koss Porta Pro, KSC75, The Plug, UR10; The House of Marley Redemption Song; Sennheiser HD 800, HD 650,
HD 600, HD 598, HD 595, HD 558,
HD 555 (also modified to HD595), HD 380, HD 280, HD202,
HD201, PX 100, Momentum On-Ear, Momentum Over-the-Ear; Shure SRH1540,
SRH940, SRH840, SRH440, SE835, SE535; Skullcandy
Aviators, Crusher, Hesh; Sony MDR-X05, MDR-XB500, MDR-7506, MDR-V6, MDR-55,
MDR-CD30 (I almost forgot about these; purchased at a garage sale about 10 years ago);
Superlux HD681, HD688B;
Ultimate Ears TripleFi 10 (family member owns them); Ultrasone HFI-780; Westone UM Pro 30, UM Pro 20, UM Pro 10.
There are some holes in my memory but I hope you get my point that I am not speaking without some experience under my belt. Also note my signature below for my current signal chain. In the absolute sense, I heard a lot of detectable resonance with the sealed Sony's I have tried, with the choice exception of the X05 and XB500 which both seemed to not exhibit this behavior from their sealed chambers. But I'll leave this to you and your ears and other discerning listeners to decide for themselves what's best for their media pleasure. I have to admit, though. The Sennheiser HD600 is a bit constricted, even for me with a technically true neutral source. It is kind of hard to explain to some, but despite the fact that the treble reaches to the very top, higher than the K701/K702/Q701, and the bass goes down to 30 Hz, the lower to middle-upper treble range has a veil that makes the music seem separated and distant. It reminds me of the stereotypical classic audiophile speaker sound: warm, cozy and detailed but not quite neutral and certainly not action-packed or with real verve or vibe. I actually sold them off yesterday because they were just a tad reserved for my tastes even after my best efforts to modify their worn pads. For me, I find the DT860 much more up my alley, as it has neutral bass, neutral midrange and just a tad extra treble to satisfy my inner detail freak. As always, YMMV.