The only sure way of knowing if you like a pair of headphones is by putting them on and listen! Headphones that cost quite a chunk of change tend to be good overall, although the price tag does not always correlate. In fact, anyone who has tried a lot of headphones will tell you that cost often has nothing to do with how good a pair of headphones sound.
Take for instance, the Hifiman HE400i headphones. They look very smart, they're extremely comfortable, and they come in at a price that belies their appearance and sound quality.
The HE400i are the twin version of the HE400S planar headphones. Both look alike and are constructed very similarly with plastic earcup housing, bevel earpads and a metal band on top of the headband pad, which is thinly padded with perforated material for breathability.
The HE400i headband yoke is also made of plastic and allows full 180-degree rotation of the earcups so, you can flip them back to front. Visually, the HE400i can be differentiated from the HE400S by the finish on the outer earcup housing, which in the case of the HE400i has a shiny chrome mirror finish.
In terms of comfort, both the HE400S and HE400i come with stock velour beveled earpads and open back, making them extremely comfortable to wear for long periods of time. Both have the same 55mm diameter inner cup, although the HE400i earpad depth is just 15mm; hence they aren't as deep as the 20mm earpads on the HE400S.
The fabric material covering the 2.5cm thick padding of the HE400i earpads is slightly different as it's not entirely made of velour fabric like the HE400S earpads. The HE400i earpads are covered with velour and pleather, which is integrated on the outside perimeter of the earpads.
The HE400i earpads do generate less heat/sweat than the HE400S, thanks to tiny perforated holes inside the perimeter of the earpad, which allows more efficient ventilation inside the earcup. The fabric material separating the speaker drivers is thin.
The HE400i planar headphones are 20 grams heavier than the HE400S, which weigh just 350 grams. That said, for a pair of electromagnetic planar headphones, both the HE400i and HE400S versions are very lightweight.
Along with perforated holes, the shallower depth of the HE400i earpads does decrease the HE400i bass response but, it allows the HE400i to have a more open and fuller soundstage with a clean treble (not too bright).
The HE400i are warm sounding with a tighter and more detailed low end bass that you could ever get with dynamic headphones, making them the best type for rap, hip-hop and EDM listening.
The HE400i 2.5mm audio ports are also recessed; hence you can only fit audio cables with straight plug connectors.
You won't have to buy an audio cable though, since a 1.5 meter long audio cable is included with the Hifiman HE400i planar headphones.
The audio cable has a braided nylon sleeve and two straight 2.5mm mini plug connectors that termite into a 3.5mm right angle connector. The plugs are made of plastic and have rubberized strain reliefs.
The HE400i planar drivers have lower sensitivity (93dB) and higher impedance (35 ohms) than the HE400S drivers; hence the HE400i sound quieter when connected to a mobile phone. To get all of their magic, the HE400i really have to be connected to an external headphone amplifier. You can buy the Hifiman HE400i planar headphones on Amazon.