Headphone is a conversion unit,  it receives media player or a receiver, close to the ear speaker into can hear sonic. Headphone is generally separated with the media player  , it uses  a plug connection. The advantage is that it will not affect other people in the situation, listen to sound alone; can be separated from the surrounding environment, in the studio, DJ, travel, sports in the noisy environment of the people very helpful. The headphone is used for telephone the radio, but with the popularity of portable electronic device , headphones are more used for mobile phones, radio, walkman. portable digital audio and video player. From the development of the audio industry, wireless headphone is still a new thing, the development time is not long, is still in the rising period, the user demands, user expectations of the value of the wireless headset is also improved, which is the industry of the new test.
You can choose different headphone according to the use. If it is a general learning and listen to the news, you can select the headset, ordinary electromagnetic earphone. If you enjoy music, you should use the headphones, if you want to enjoy high quality music, you should choose high fidelity headphones, such as the quality of moving coil type or capacitor earphone. It is convenient to use, optional wireless headphones, In addition, headphones, can listen to radio programs.
Impedance: impedance is short for the AC impedance, it is the sum of coil DC resistance and the inductance of the coil and the Z= (R2+ 2L2 1/2).
Range: instruments or voices can reach the treble and the bass.
Timbre: also called yinpin, one of the basic attributes of sound, such as the erhu, Pipa are different kinds of tone
Coloring sound:like the sound that a man speak to a jar.
The sound field: the sum of speakers produce different kind of sound .
Location: The fixed position of sound equipment of the 3D distribution.
Distortion: output cannot completely reproduce the input device, the waveform distortion or signal component changes.
Dynamic: record the maximum and minimum ratio of information’s allowance 
Knot  force: the ability to focus on audio and video audio playback.
Transparency: audio form is clear and easy to read degree.
Voice: refers to a high proportion, in full, bass heavy burst of appropriate, appropriate, adequate, high tenor sounds have a certain elasticity. A sound level: level refers to reproduction can reflect the overall sense of a band.
Clearness: refers to the speech intelligibility, structured music.
Balance: refers to the consistency of music of each voice, proportion, left and right channel .
Strength: refers to the sound is solid and strong, can have a sense of being out , and can reflect the dynamic range of the sound source.
Round: refers to the beautiful sound, shiny and not sharp noise.
Soft: refers to the voice of relaxation is not tight, treble is not harsh, pleasant and comfortable sense of hearing.
Fusion: refers to the sound the whole blend together, the overall sense, good sense.