The blue line and the eq recommendations in the charts are just that, recommendations.
You can use the raw, dark line to actually equalize your speakers. I used Audacity fliter-curve EQ set the window to 70% opacity and traced out the line.
It was not a perfect overlay, and I had to move the image a small amount each time to line up that area so every 200 Hz or so, I moved the image to the left to lineup the logarhythmic chart lines.
I now realize why headphones and earbuds roll off 10-20 kHz so much, it is a bit shrill especially an odd effect on vocals that isn’t there on normal speakers with flat eq. So there is some merit to the treble roll off for certain.
I however do not agree with the large increase for 2 - 8 kHz. I think the treble increase can be excessive, and you may like a more equalized sound in this area
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I believe I found that a a year or so ago when my MDR-G42’s broke and I was looking for a replacement…it does not have MDR-G42’s and from what I’ve read the Sony models meant to replace them are garbo. Worse now is the fact wired is a DoDo bird…
Sony MDR-7506
Released sometime in very late 90s
Great bass, flat midrange and smooth rise and fall for treble
Yeah but how do they compare to my trusty MDR-G42’s? The chart looks like something I’d not like. This is one of those hidden gem situations. I bought those things in the 90’s for like $20 CDN. However they were the flattest I’d heard. Over the years I’ve tried all kinds of brands and models from cheap $5 drug store crap to hundreds of dollars and they all kinda sucked. I sit in front of engineering monitors all day…and it’s been that way for like 30 years. I want FLAT. 
Having said that they are a newer model and all the reading and research I did was littered with accounts saying none of the newer MDR’s were any good compared to the generation I owned.
While I’d like to find a replacement for my MDR-G42’s it’s also kinda moot as you can’t buy mp3 players anymore and even if you could soon everything will be BT only.
Ultimate ears reference monitor IEMs might be close
Pioneer, Rhode, Shure Plantronics and Yamaha have good looking charts if you look through the list