Or they're just not as good as you were hoping. The 505 wasn't very good to my ears. The Monitor 10 is the only vintage pioneer I'd say is worth trying. Well, excluding the unobtainable ones of course.
I really hope you're right, but I also really doubt it. The T50RP has some of the most abrupt bass roll off I've ever seen in a modern headphone, and it's only fixable with closed cups and an assload of damping. The TH500RP uses a transducer based off the T50RP, and unlike the T50RP, it's fully open.
Monitor 10-II never distorts on any of these 20Hz is a massage 16Hz is audible 12Hz can be felt this is at normal listening levels, NOT cranking them when I crank them 10 is a massage, and theres still no distortion at all
1: AKG Q701 and Sennheiser HD250 Linear II: Too close to call. Equally technically capable, Qs are a bit more natural but have bass roll off and upper midrange hiss, Linear II has better extension in both directions but can sound way too bright and bassy. Both have huge, intricate soundstaging and are very fast and clean. HD250 isolates like crazy. Q701 is prettier and feels nicer in the hands.
2: Pioneer Monitor 10-II: There are some really nasty cup resonations going...