Sennheiser HD 650 vs Shure SE215

The sound signature is near neutral but with a little emphasis on the lower frequencies. The bass is slightly forward with good punch and tightness. Explosions will have good rumble, without overpowering the other frequencies.
The mids are warm and clear, adding extra body to the sound. Game dialogue will be easy to hear.
Highs have good clarity, but are not forward in any way, so harshness is minimized.

The H650 is popular for its near neutral sound, which makes it quite versatile. The headphones can give a great casual listening, gaming, and movie watching experience yet are accurate enough for pro audio mixing. They are also lightweight and comfortable so you won't have any issues wearing them for hours.

Clamping force is not too tight. The ear pads and headband feature memory foam which are covered by velour material. The pads feel really soft on the head and allow airflow for minimized heat build-up/sweat.
The headband also features similar cushioning materials and minimizes pressure spots on the head.

The open ear cup design allows the sound to blend with your surroundings, giving it a natural width. It will also be easier to identify the direction of sounds, which can really help immersion.

The HD-650s do not feel heavy at all. They are usable for long music listening, movie or gaming sessions without feeling pain or strain on their head and neck.

While the cable connectors are proprietary, they can easily be removed from the ear cups with a firm pull. The popularity of these headphones means that there are a lot of aftermarket cables that can be bought.

Bass is emphasized so there is a good bit of thump while staying controlled. Mids are rich, highs avoid sibilance, though they're a bit rolled off.
Soundstage is okay--instruments are separated out enough for them to not sound like they're all coming from the same place, but it's not particularly wide.

The memory foam eartips mold to your ear to provide amazing sound isolation, though there's a bit of a learning curve to using them. You have to press them together before putting them in and then allow them to expand in your ear. Once expanded they will take the shape of your ear and that way provide excellent noise isolation.

The earphones also come with silicon tips which are easier to use than the foam ones and also last longer.

The SE215 earphones have a negative profile, optimized nozzle angle, over-ear fit and memory eartips that ensure the earphones stay in place comfortably regardless of situation. You can even lie on your side with them.

6 types of plugs (silicon/ foam: S/M/L).

SE215 earbuds use tough plastic earpiece shells, have a robust kevlar-reinforced cable, a sturdy Y-splitter that's difficult to bend and an L-shaped plug that adds additional strain relief. They won't break if you snag them, drop them or sit on them. They're also completely sweat proof so you can use them while working out without having to worry about damaging them. They're durable enough for professional stage use for which they were specifically designed for.

The SE215's 6.4-ft. cable is very thick, and further reinforced at the left/right split point. Reviews confirm the durability benefits of its heavy-duty design. If it ever does break, the cable is built to detach safely from the earpieces, allowing replacement.

The optimized angle of the earbuds, over-ear fit, and memory ear tips ensure that the earphones stay in place comfortably regardless of situation. These are also sweat-proof, so they're a great option for active use.

Shure provides a warranty against defects in materials or manufacturing for two years.