Takstar pro82 in red, isk mdh9000 in purple. As you can see pro82 has better extended bass but ISK is a lot bassier compared to midrange. (Edit: I think isk's have more bass than the measurements show) Both have quite a dip at 2khz-5khz area, so both lack some upper midrange resolution. That is the reason why I don't like pro82 much. Like
@ftoss said pro82 is a lot brigher. I concur what he said. Mdh9000 is fun, bassy headphone with big (big for any closed headphone regardless of price) and pro82 is more neutral. Even though MDH9000 does not have the best subbass extension it is a basshead can done right. Miles better than Bosshifi B7 for example. Two very different headphones, so pick your poison
If one is not sensitive to sibilance (4-5khz peak on the graph) I definately recommend Msur N550 over both. Allthough bright N550 is very clean so the highs sound pronounced but not particularly harsh or grainy. Superlux hd681, takstar pro80 and hi2050 all suffer from too much brightness, buf it's the lack of grain that sets msur apart from the competition. It can't match the bass extension of pro82 nor does it have jamming bass and big soundstage like mdh9000. However N550 sounds so transparent, clear and detailed that it is the only budget headphone I've heard that I would call an actual giant killer. Yes, theyre bright and mids could use more body but the sheer lack of "veil" puts them in a league way above its price range.
all three in the same graph