The lowest frequency at which the device produces audio. The lower the low-frequency response, the stronger and juicier the bass.
The highest frequency at which device produces audio. The higher the high-frequency response, the clearer and crispier the treble.
3.has passive noise reduction
The device sits tightly in place, creating an acoustic seal which reduces background noise and prevents your music from leaking out.
4.has active noise cancellation (noise control)
This type of device allows you to listen at lower volume levels, causing less ear fatigue as you don't have to crank up the volume to overcome background noise. Ideal for plane rides and morning commutes.
Devices with a higher sound pressure level are generally louder when supplied with any given audio source.
Devices with neodymium magnets are lighter and more powerful than those which use ferrite magnets. They also have more bass and clear high notes.