2007年7月29日 星期日

The advantages of the Rubber Holder - 使用Rubber Holder的好處

Microphone is a component to receive the sound, therefore it is possible to receive any other sound
which happens near the microphone at the same time, for instant, when we touch the casing;
or the sound made from the fan, the keystroke, and the speaker. However, the rubber holder can
be very helpful to reduce this vibration of sound when the microphone receive the sound, and gives better results.
There are many specifications of holders can meet our microphones without new molding. However,
if you have any special requests for the mechanism, we can also mold for you or offer the useful suggestion on acoustic.
麥克風是用以接受聲音的元件,但它同時也會收到機構內外任何頻率的振動,
如手接觸機殼的磨擦聲,風扇聲,按鍵聲,喇叭聲...等等.
而Rubber Holder可以隔離這些振動,聲音,至少可大幅的衰減之,
使麥克風在收音的時候,可以有更好效果,
我們有許多規格的holder可配合我們的麥克風使用,不需開模,
但若機構上有特殊的要求,我們也可以開模來配合,或是提供聲學上的建議.

2007年7月20日 星期五

Small size speaker but generate higher sound pressure level?

In order to increase sound pressure level, we need to vibrate more air molecule by more power under unit time.
For the two sizes speakers, the area of diaphragms of the 15mm speakers are around 176mm square (7.5*7.5*3.14),
and the 20mm size speakers are around 314mm square(10*10*3.14). The 20mm speakers are only bigger by
5 mm/ 25%, however, the diaphragm are bigger by 78%. Therefore when we input the same power, the 20mm
speakers can vibrate more air at the same time, and it result in higher sound pressure level.
Generally, the speaker in bigger size can provide lower frequency response which is better for human’s
audition. On the other side, we can also provide the smaller speakers more power to make higher sound
pressure level, but it is limited by,
1. Acceptability of the diaphragms2. Thermolysis of the speakers3. After increasing the power, frequency response will change too(because thicker diaphragm, heavier coil..etc)
Therefore, what we can do is reform the material and the structure of the speakers to increase sound pressure level,
but if it is possible to choose the bigger size, the problem of the lower sound pressure level will be improved immediately.
想要有大的音壓,就必需在單位時間之內,以更多的能量來推動更多的空氣分子,
以二種尺寸來說,15mm的喇叭,振膜的面積大約是(7.5*7.5*3.14=176mm平方),
而20mm為(10*10*3.14=314mm平方), 直徑20mm的喇叭雖然在尺寸上只大了5mm / 25%,
但在振膜的表面積卻大了78%,在我們給予這二個喇叭一樣的功率時,
所聽到的聲音大小,就會有很大的不同,就是因為20mm的喇叭可以在同一時間內,
推動更多的空氣分子.
而且更大的尺寸,通常低頻響應也會比較好,人耳所感受的的聲音也會比較好聽些,

當然我們也可以給小喇叭更大的功率,使之發出更高的音壓,但受限於
1. 振膜的承受能力,
2. 喇叭散熱能力,
3. 功率加大後頻率響應特性的改變( 膜片需加厚,音圈變重....)
所以我們只好從材料,喇叭的結構來做改善,盡量將小尺寸的喇叭,聲音做大,
但如果尺寸容許的話,換大一號的喇叭,就可以馬上改善聲音不足的問題囉.

2007年7月13日 星期五

The buzzer has noise 蜂鳴器有雜音

When the sound which the buzzer generates is not a clear beep sound, we call it noise or broken sound. There are two possible ways to cause the noise.
Improperly used If the voltage we input is too high, the diaphragm will easily touch other components, which causes the noise. When we set the wrong frequency instead of the rated frequency is easy to have noise. For example, if the rated frequency is 2730Hz, but the user input 2400Hz, the noise appears easily, especially within the range 10% ahead of the rated frequency.
Disqualified A diaphragm of the buzzer is just set on the braces not firmly attached. Therefore the external force will move the diaphragm and result in the noise. When we assemble the buzzer, or in the process of user’s production line, if there are some iron chippings invade into the buzzer, the noise will also be caused.

當蜂鳴器發出的聲音,不是清脆且單純的嗶聲時,我們會稱為是雜音,或是破音,
蜂鳴器雜音的成因,可分為二種可能,
使用不當:
給予蜂鳴器的電壓過高: 使膜片敲打到內部的其他零件,產生零件撞擊的聲音,
使用的頻率不對: 未將頻率設訂在額定頻率上 , 例如規格是 2730Hz , 使用者卻給 2400Hz 就很容易有異音 , 尤其在額定頻率前10% 範圍最會產生異音.品質不良:
膜片異位: 電磁式蜂鳴器的膜片是"放"而非黏在支架上,故有可能因為激烈的外力使膜片跑出該在的定點,而造成雜音.
有異物侵入: 在組裝蜂鳴器,或是使用者的產線加工時,若有小鐵粉,鐵屑進入蜂鳴器內部,也會造成雜音的發生.

2007年7月3日 星期二

About waterproof speaker 防水喇叭

Generally speaking, a paper diaphragm speaker is easily to have the problem of molding or distortion in a humid environment, and is certainly damaged in the water. On the other hand, the mylar diaphragm speaker is normally waterproof that it can work with drip, fog, or even slightly in the water if we use the rubber ring to fix the diaphragm instead of paper ring.
Another important thing is that all the diaphragms of the speakers are very thin, and the pressure of water might distort even break the diaphragm if it is too deep.
In conclusion, the mechanism design is also very important, especially the joint should be completely sealed in order to reach waterproof function.
一般而言,,紙盆的喇叭在潮濕的使用環境下,比較容易有發霉或是變形的問題,泡水更是會立即的損壞,
而採用塑膠振膜的喇叭大致上都有撥水的能力,亦即水滴,水霧並不會損壞喇叭,
若配上橡膠的墊圈取代紙墊圈,則輕微的泡水也不會有問題,
要注意的是,喇叭的振動膜片都很薄,若水深過深,強大的水壓有可能使膜片變形,甚至破裂!!
當然機構設計上也要注意,喇叭與機構的間隙都必須要密封好,才能泡水的喔!!