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| 1.
Advantages of diamond as a high-frequency diaphragm material: |
It has been a long time since loudspeaker engineers are searching for one lightweight but rigid materials to develop high-frequency diaphragm. Based on above characteristics, diamond meets their requirements.
When we mention one acoustic frequency response curve, the so-called resonance frequency usually stands for the position where the resonance becomes strongest, rather than “the beginning of resonance”. Taking one 50μm-thick conventional aluminum diaphragm for example, the first resonance frequency appears at about 28.5kHz. It seems that this value is already beyond the audible range of human ears (20Hz~20kHz). However, in fact, in the vicinity of the upper limit of such range (ex. 20.5kHz), it is quite possible that the diaphragm has already resonated slightly. What we heard might be only unreal sounds.
In view of this drawback, the resonance behavior around 20kHz serves an important criterion for selecting a substituted diaphragm material. Roughly speaking, “the smoother the frequency response curve” and “the later the first resonance frequency appears”, the better the high-frequency tweeter.
The resonance frequency of a diaphragm is closely linked to “Young’s modulus” and “density” of the selected material. Calculated from the coefficient of resonance frequency provided by Table 1, if the diamond diaphragm has a thickness of 40μm, one particularly high first resonance frequency (~80.8kHz) is expected. Even under practical test, the curve of the high-frequency diamond tweeter did still remains at the same level before 40kHz, that is incomparable with other common diaphragm materials like Al, Be or Ti.
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Al |
Be |
Ti |
Diamond |
| Young’s Modulus (GPa) |
71 |
318 |
120 |
1000 |
| Density (kg/m3) |
2700 |
1850 |
4500 |
3500 |
| Coefficient of Resonance Frequency |
5128 |
13111 |
5164 |
16903 |
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Table 1: Properties of four high-frequency diaphragm materials |
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| 2.
Product appearance: |
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Kinik diamond diaphragm comprises not only one convex, dome-shaped film (Fig. 1, left) but also one “skirt” along its periphery, which could be mounted onto voice coils (Fig. 1, right). Under irradiation with a light beam, the diaphragm has a good shine. |
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| Fig. 1: Kinik diamond diaphragm comprises (left) one convex film and (right) one skirt |
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| 3. Characteristics: |
| Fig. 2 shows Raman spectra of Kinik diamond diaphragm. One narrow characteristic peak (at 1332cm-1) was recognized, as a result, it could be concluded that there exist high-content sp3 diamond structures in Kinik diaphragm. |
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Fig. 2: Raman spectra of Kinik diamond diaphragm. The red curve represents the convex, while the green the inner surface. |
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| Fig. 3 shows the frequency response curve of Kinik diamond diaphragm ranging from 400Hz to 20kHz. At 20kHz, the curve broadly remains smooth and no serious resonance is observed. |
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Fig. 3: Frequency response curve of Kinik diamond diaphragm |
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| 4. Product specification: |
| Based on abundant experiences in diamond technology, Kinik dedicates to the development of diamond diaphragm (Fig. 4) over a long period of time. We have obtained numerous patents in Great Britain (GB2429367, GB2427878) and the United States (US7,435,363). Our current specification for mass production is as follows: |
| Weight (g) |
0.05 |
| Height (mm) |
4 |
| Thickness (μm) |
30-40 |
| Diameter (mm) |
25.6 |
| Radium (mm) |
23 |
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Fig. 4: Kinik diamond diaphragms of different sizes |
This specification is only for reference. We also accept other customized specifications. If you want to get more details or have any question, we stand always enthusiastically to serve you. |
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| Customer Service：kinik_rd@kinik.com.tw |
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