 |
Frequency Resonance Range： |
| |
 |
A good earphone should have the frequency resonance range around 16 ~ 22KHz (IEC581-10 about 50~12.5KHz) |
|
Human hearing is limited to frequencies around 20 ~ 12KHz |
|
Musical frequency ranges around 20 ~ 20KHz |
|
| |
|
|
Impedance： |
| |
Generally it is measured by 1Khz and earphones with lower impedance (16Ω、32Ω) are most popular. For different product applications, earphones with 100Ω or above are available as well. |
| |
|
|
Earphone Frequency： |
| |
Sounds are made from the high and low speed of vibrations of physical materials (second/per time). High frequency creates the higher sound; low frequency with the lower sound.
Human ear hearing range in the phonic frequencies: 100 ~ 3.5 KHz and human ear is most sensitive and feeling noising around 3KHz. Most of the time, the earphone is produced based on the observations of the frequencies as the flat curve. |
| |
|
Usually phonic sound frequency curve range from 100Hz ~ 5KHz |
|
Musical sound has the frequency curve range from 20 ~ 20KHz |
|
| |
|
|
Harmonic Wave Distortion： |
| |
One kind of wave distortion with lower the distortion, better the sound quality (as the more dedicated sound to the ear relatively). |
| |
|
|
Factors affecting the sound quality： |
| |
suitable impedance characteristics, vibrating components, the magnetic movement, the physical and interior design |
| |
|
|
Sensitivity Sound Pressure： |
| |
the earphone (It is measured in decibels (dB) with the larger the sound pressure, the louder the sound) |
| |
|
|
Maximum Output and The Sound Pressure： |
| |
5 ~ 12mW is the common power requirement. The maximum sound pressure 105 ~ 112dB by 1Khz measurement has been stated as a new regulation. |
| |
|
|
Receiver Diaphragm Thickness： |
| |
Commonly used are 6μ、9μ、12μ thinner membrane for its more extensions in the frequency range and the sound quality is more soft. However, the distortion is relatively hard to control. |
| |
|
|
Receiver Diameter and the cavity： |
| |
Diameter may range from 8ψ to 15.4ψ. Mostly earphones with diameter above 25ψ are ear-clip type or headphone type. The bigger the dimension, the easier to control the sound frequency while relatively material physical characteristics have better performance in lower frequency and smaller sizes have moved to higher frequency. The cavity and the exterior appearance are the crucial factors for sound quality performance when composing an earphone |
| |
|
|
10. Magnet（loadstone NdFeB）： |
| |
powerful magnetic permanent magnet has the excellent features of high coercive force, high residual induction and maximum energy product |
| |
|
|
Earphone Physical Structure： |
| |
 |
|
Plug Types： |
| |
2.5φ (phi) Plug |
| |
 |
| |
3.5φ (phi) Plug |
| |
 |
|
Wire/Cable Types： |
| |
 |
|
Measuring Equipment： |
| |
 |
| |
 |