I think it’s fair to compare the Grados and HD598, but the M50 is very different and seems not to fit in that comparison. The DT770 is a better comparison to the M50, although the 770 is a better more expensive item. A long time ago I had a Grado 325 and a Sennheiser HD565 – very similar, very enjoyable. Today for that type of sound I might choose the Soundmagic HP100.
EQ controls: Equalization, more commonly referred to as EQ, controls the different aspects of sound that come through your headphones, and some headphones come with custom apps that let you adjust the EQ in granular detail. With the right EQ controls, you can add more treble, bump up the bass, or just create a sound profile that’s suited to your tastes. If you’re into customizing how your music sounds, look for headphones that work with an EQ app.
Semi-open headphones, have a design that can be considered as a compromise between open-back headphones and closed-back headphones. Some[who?] believe the term "semi-open" is purely there for marketing purposes. There is no exact definition for the term semi-open headphone. Where the open-back approach has hardly any measure to block sound at the outer side of the diaphragm and the closed-back approach really has a closed chamber at the outer side of the diaphragm, a semi-open headphone can have a chamber to partially block sound while letting some sound through via openings or vents.
Open back usually results in more natural sound, but they leak sound in and out. This means you probably can’t use them in a library or a plane flight since the sound of your music will leak out and disturb the people around you. You also can’t use them on loud public places since noise from the outside will disturb your music. Therefore, even though open back would give you more natural reproduction, for these reasons their use is limited to mostly at home or in the office (if you have your own space that is).
The Soundsport Free, released in the fall of 2017, are Bose’s first truly wireless earbuds. They utilize the same StayHear+ Sport tips as the company’s other in-ear headphones, making them naturally more sweat-resistant and more secure than AirPods. They work with the Bose Connect app, which is pretty basic but does have a “Find My Buds” feature that, when enabled, can help you find your earbuds should you misplace them.
The Sony noise-cancelling headphones are a tiny miracle. They’re great at blocking the outside world, so you’ll hear your music and nothing else – at a price point that’s less than $50. Wired headphones can be a tough sell for those who’ve grown accustomed to wire-free listening, but if you’re all right with a wired connection, this pair is an easy choice.