Because i didnt have anything better to do for the afternoon i decided to compare them right away.
I took a few songs from several different genres that i would think to reveal differences in the whole frequency range. And these are for stock Pro 82 and SHP9500.
First overall sound signature: Pro 82 sounds more colored to me, there seem to be more spikes, humps and bumps. SHP9500 sounds very even and flat and more "true to life" to me. Clarity is about on the same level, SHP9500 might have a slight edge here, Pro 82 sounded sometimes a bit muddy, not in its truest meaning but in comparison. Both are very detailed sounding headphones. Pro 82 has livelier and "funnier" signature on it while SHP9500 is more refined and analytical.
Then the bass, i have to say that i dont really care much about bass and im not a huge basslover in general. Bass on Pro 82 is more mellower and fuller, SHP9500 is much lighter on bass and sounds more neutral and tighter to me. Both remain good control and sound great to me in this region.
Lower mids on Pro 82 can sound like they are a bit "sucked out" from the mix and get covered by upper mids and lower treble. This makes the entire midrange sound a bit thin, its quite noticeable in some tracks with lots of guitars and male vocals for example. In top of that upper mids can sound a bit metallicly (is this even a real word? lol) sharp or harsh. SHP9500 sounds very natural and even through the midrange and has smoothness on it that is sometimes missing from Pro 82. I prefer SHP9500 slightly over Pro 82 here.
Both have kind of dark vibe on treble. Slight harshness continues here with Pro 82 and treble sounds more "in your face" compared to more relaxed highs on SHP9500, i can live with it but it can be distracting in some songs. Both can sound borderline sibilant, to my ears its more noticeable on Pro 82 (not sure about this but thats how it sounded to me). Some people have criticized SHP9500 for having very sharp/piercing/harsh/whatever treble but i cant simply hear that. But both have lively and sparkly characteristics on treble, Pro 82 has more overall energy on it that SHP9500 is kind of missing. Hard to say which one i prefer here, maybe SHP9500 because its treble sounds less fatiguing to me which makes them a better choice for longer listening sessions.
Comparing their soundstage is not very fair because SHP9500 is an open back. Pro 82 sounds more condensed and compressed (aka. more closed) but i have to say that soundstage is not phenomenal in SHP9500 either, of course its better but its not going to blow you away or anything. Both have good sound separation.
This is where i came to after promptly comparing them to each other. SHP9500 sounds better to me overall but Pro 82 is not bad by any means and i can enjoy both. Pro 82 = better for enjoyment and "fun"-listening, SHP9500 = more refined audiophile-headphones. If you have any questions feel free to ask.