Re: the Mysphere 3.2 - it's more of a philosophical point if you talk to Heinz Renner about this. With listening volumes that cause no mid to long term hearing damage, the bass energy level is sufficient on the Mysphere 3.2 although the fundamental frequency is only the same as the bass heavy K1000 (50hz). And this is indeed a restriction of the driver design itself and from a design to optimize for efficiency and finer control. The driver itself is actually larger than the K1000, utilizing a unique square design to get more surface area at a fixed enclosure size.
@biscottino Modern genres do indeed have more dynamic range than older recordings but unless your pair has quality issues, bass distortion should not show up before the drivers are pushed significantly beyond 100db at ear point. I haven't run into bass distortion issues on the Mysphere 3.2 at my listening levels (even the louder "reference" level of around 95 db that I use to critically evaluate headphones), but each person's listening habit will differ on that point.
I don't have a stance on whether this is a good idea - Heinz wanted something that will work well with headphone amps (the AIC10 is an excellent example), and overall the trade-off seems like a reasonable one given that performance is only sacrificed at listening volumes where arguably, people should not be listening at for periods of longer than 10-15 minutes. That said, it does limit the overall dynamic range of the cans
if you chose to listen at those volumes.
With the SR1a's the design should work until 120dbs at ear point - far louder than anyone should ever be listening headphones to, at least for more than 1-2 minutes. The fundamental frequency is lower than the Mysphere 3.2 at 30hz, but if you run music with a lot of sub-bass you'll still notice that energy is lacking at the <30hz range. Overall, the bass on the SR1a is much better than the Mysphere 3.2, and I would indeed say that they are technically superior headphones - although the Mysphere 3.2 will happily work on strong portable sources, and is much more forgiving of bad vocal recordings because of its particular midrange imaging.
Headphone amps don't usually have sub-100hz issues, unless we're talking about old or rather low-budget designs. Bass response on speaker amps is probably better for each price point, but if you look at a GSXmk2 against something like a J25, I don't think that you can say that one's bass is better than the other.
Driving the Mysphere 3.2 on speaker amps is mostly a matter of tolerance to the noise floor. I've generally had pretty good experiences, and something like the Nagra Classic INT (or CH monoblocks or an AHB2) is entirely noise-free on the Mysphere 3.2. I bought the Nagra for triple duty on the Mysphere, 1266 phi and SR1a and it works pretty well for all three cans.
Hifiman in trouble now~ 
