Piezo Element 有關壓電陶瓷蜂鳴片

Piezo Element
The good points to choose piezo element is that the cost is lower than others and you can design the sound chamber to reach a special sound. However, during assemblage, the experienced skill of soldering wires is strictly demanded, otherwise large defective products such as small sound, soundless, deviated frequency or electric leakage might happen. Defects are resulted from:

Piezo element and chamber both have their resonance points. How to match the two resonance points to get loud SPL and wide frequency range, the mechanical design has become a test. Material, thickness, size and depth of the sound hole and the capacity of chamber are the factors which will affect the chamber’s resonance.

The bad fix method
There are two methods for fixing the piezo elements:

Nodal mounting method
This method is to fix the nodal diameter of buzzer element to the supporting ring of the plate; better SPL can be obtained. Finding the pivot and resonance frequency of element, then the piezo element will have max vibration and SPL.

Circumference Fixing Method
This method is to fix the outside circumference of the buzzer element to the supporting right of the plate. Wide frequency range can be obtained, and easier to design. For these two methods, flexible adhesive such as silicon should be used between the buzzer element and the support ring.

Defective soldering
During the soldering, the size and position of the solder point should be the same. The temperature and pressure should be well controlled to avoid badly soldering, which will cause short circuit or insufficient isolated impedance. Besides, the iron need to be separated for the two solder points, because the ceramic wafer contain a large amount of lead, using the same iron will cause the fail of RoHS test.

有關壓電陶瓷蜂鳴片
選用壓電陶瓷蜂鳴片的好處是, 低成本,可自行設計音腔來達成特殊的聲音要求,但在組裝,焊線時的技術要求較嚴,若無相關經驗或技術,可能會有大量的不良品產生,小聲,無聲,頻率偏差,漏電都有可能會發生.這些不良大都起因於:

蜂鳴片固定方式不良
蜂鳴片常見的固定方式有二種,
節點固定(左圖):可以獲得較高的音壓,但需知道蜂鳴片的諧振頻率,找到片子振動的支點,使蜂鳴片可產生最大的振動,就可達到最大的音壓,

圓週固定(右圖):可以獲得較寬的頻寬,設計上也比較簡單,這二種方式都最好以矽膠(Silicon)等有彈性的膠來粘合機殼跟蜂嗚片,使蜂嗚片容易振動.

音腔設計不良
蜂鳴片及音腔都有各自的諧振點,如何將二個諧振點配在一起,取得最大的音壓,或是較寬的頻寬,這就考驗機構設計的能力,會影響音腔諧振的因素有: 材質, 肉厚, 音孔大小,音孔深度,音腔容積..等.

焊接不良
焊線時的焊點大小,位置都要一致,烙鐵的溫度,時間,壓力也要控制,以免把陶瓷片焊壞,造成短路或絕緣阻抗不足,另外二個焊點的烙鐵需分開使用,因為陶瓷片含大量的鉛,若再來焊銅片,會造成RoHS檢測不過的問題.

The influence of operation voltage on SPL of a buzzer

The SPL of a buzzer does not have a geometric ratio relation with the voltage directly, especially close to the rated frequency.
According to the graph below, at 2000Hz, we have 3V with 74dB, 6V with 80dB, and 12V with 90dB results; however, at 2048Hz, we have 3V with 84dB, 6V with 87dB, and 12V with 90dB.
Because the bandwidth of the buzzer will widen when the voltage raises, therefore we should pay more attention to the output frequency, even 100Hz difference might cause a big difference in 10dB!

Buzzer and Speaker 蜂鳴器與喇叭的比較

喇叭與蜂鳴器都是發出聲響的零件,若只是想發出一些警告音,提醒音,這二者其實都是可以使用的:Buzzer and speaker are the acoustic components that can generate sound, if you just need sound to warn or remind, both of them are fine.

蜂鳴器分為電磁式及壓電式二大類,在耗電流,尺寸,頻率,驅動方式上有些不同,但基本上都是將某一個頻點的音壓拉到最高,以期用最小的尺寸,就可以發出很高的音壓,若不在諧振點的音壓就會很小,甚至會相差20dB以上,且蜂鳴器的聲音,由於是用方波發出來的,人耳聽起來就比較刺耳一些,We divide buzzer into piezo and magnetic buzzer. There are some differences in power consumption, dimension, frequency and drive method between piezo and magnetic buzzer, however, both of them basically pull the SPL to the highest at a certain frequent point in order to generate as high SPL as possible in the small size. The SPL will be very low if it is not at the resonance point, even 20dB difference. By the way, the sound of buzzer is drove by square waves; therefore it is harsh to the human ears.

小喇叭是以弦波推動,相較於蜂鳴器人耳聽起來會舒服許多,但因為頻寬較寬,可用的頻率也較低,故在同尺寸時,音壓一定會小於蜂鳴器,且需要音箱的輔助來增進低頻的響應,不然整體的聲音會很小.Micro speaker is drove by the sine waves, to compare with buzzer, the sound is much more comfortable for us. However, the bandwidth is wider, and the frequency is lower, therefore, the micro speaker’s SPL must be lower than the buzzer with the same size, and also need enclosure to help the low frequency, otherwise the sound will be very small.

The difference between the speaker and the receiver 喇叭與受話器的不同

The basic structure of the speaker and the receiver is almost the same; the diaphragm generates the sound by the reaction upon the sound coil and magnet.
The main diversities are as below:

The different usage Depend on the size of the speaker; the distance between the speaker and the user’s ears is normally from several dozens of centimeters to several meters. However we always nestle up a receiver against our ears.

The different material of the diaphragm and the sound coil In order to bear the higher power, the diaphragm of the speaker is usually thicker than the receiver, the thinnest one is 18u. The larger of the dimension and the power is the heavier the diaphragm will be. The receiver takes the lower power, but requests for better low frequency curve; therefore we usually use the diaphragm with the thickness from 6u-12u. Besides the diaphragm, the receiver often works with a piece of paper or cloth to adjust the frequency response, which can help to meet all kinds of standards or to match up the resonant box of the mechanism.

The different electronic characteristic  We often see the speaker with impedance of 4-8ohm, the too high impedance leads to the higher power to drive the speaker, normally is from 0.2W to several dozens of watt. Depend on the circuit design, the impedance of the receiver is from 16, 32 to 150ohm. The general power is only from 0.01W to 0.1W.

喇叭(Speaker)與受話器(Receiver)的基本構造是大同小異的,都是透過音圈與磁鐵的作用力,帶動振動膜來發聲,
有幾點較大差異如下:
使用上的不同:
喇叭通常是離使用者的耳機有幾十公分甚至幾十公尺的距離,視喇叭的大小不同而定,
而受話器是緊貼著耳朵來使用的,

膜片,音圈等材質不同:
喇叭需承受較大的功率,故膜片厚度都較厚,從最薄的18u開始,尺寸愈大,功率愈大,膜片就會愈厚重,
受話器的功率小,但要求低頻曲線要好,故一般採用6u-12u的膜片,
除了膜片之外,受話器通常會加貼調音紙或調音布,來調整頻率響應,以符合各種的規範或是來配合機構的共嗚腔.

電氣特性上的不同:
喇叭最常見的為4-8ohm,太高的阻抗會使喇叭需要更高的電壓才能驅動,0.2W到幾十W都有
受話器從16,32,64ohm到150ohm都有,端看客戶的線路設計匹配,一般的功率只有0.01W到0.1W.

Test condition makes the impact on the sensitivity of microphone 測試條件對麥克風靈敏度的影響

Generally speaking, the sensitivity of the microphone will increase when we raise the impedance at 2.2K of RL, the results as the graph 1 & 2.
The sensitivity also rises if we give higher voltage to the microphone, graph 3 & 4.
一般而言,在RL的2.2K阻抗加大,麥克風的靈敏度會變高,結果如圖一二,
V+給麥克風的電壓愈高,麥克風的靈敏度也會變高,如圖三四,


RL 2K =>3K ohm

RL 2.2K => 1.0Kohm










Voltage 2V=>4.5V










Voltage 2V=> 1.2V











Equipment : B&K 2012 + B&K 4227
Microphone : 6.0mm x 2.7mm -42+/-3 dB

How to choose a buzzer 如何選用蜂鳴器

How to choose a buzzer

There are many different kinds of buzzer to choose, first we need to know a few parameters, such as voltage, current, drive method, dimension, mounting type, and the most important thing is how much SPL and frequency we want.Operating voltage: Normally, the operating voltage for a magnetic buzzer is from 1.5V to 24V, for a piezo buzzer is from 3V to 220V. However, in order to get enough SPL, we suggest giving at least 9V to drive a piezo buzzer.Consumption current: According to the different voltage, the consumption current of a magnetic buzzer is from dozens to hundreds of mill amperes; oppositely, the piezo type saves much more electricity, only needs a few mill amperes, and consumes three times current when the buzzer start to work.Driving method: Both magnetic and piezo buzzer have self drive type to choose. Because of the internal set drive circuit, the self drive buzzer can emit sound as long as connecting with the direct current. Due to the different work principle, the magnetic buzzer need to be driven by 1/2 square waves, and the piezo buzzer need square waves to get better sound output.Dimension: The dimension of the buzzer affects its SPL and the frequency, the dimension of the magnetic buzzer is from 7 mm to 25 mm; the piezo buzzer is from 12 mm to 50 mm, or even bigger.Connecting way: Dip type, Wire type, SMD type, and screwed type for big piezo buzzer are usually seen.SPL: Buzzer is usually tested the SPL at the distance of 10 cm, if distance double, the SPL will decay about 6 dB; oppositely, the SPL will increase 6 dB when the distance is shortened by one time. The SPL of the magnetic buzzer can reach to around 85 dB/ 10 cm; the piezo buzzer can be designed to emit very loud sound, for example, the common siren, are mostly made of piezo buzzer.
Introduction of magnetic buzzer - Introduction of piezo buzzer
如何選用蜂鳴器
蜂鳴器的種類規格繁多,需先知道幾個參數 ( 電壓,電流,驅動方式,尺寸,連接/固定方式),當然更重要的是,想要獲的聲音 (音壓大小,頻率高低),
工作電壓: 電磁式的蜂鳴器, 從1.5到24V, 壓電式的從3V到220V都是可行的,但一般壓電的還是建議有9V以上的電壓,以獲得較大的聲音.
消耗電流: 電磁式的依電壓的不同,從幾十到上百毫安培都有,壓電式的就省電的多,幾毫安培就可以正常的動作, 且在蜂鳴器啟動時,瞬間需消耗約三倍的電流,
驅動方式: 二種蜂鳴器都有自激式的,只要接上直流電(DC)即可發聲,因為已內建了驅動線路在蜂鳴器中了,因為動作原理的不同,電磁式蜂鳴器要用1/2方波來驅動,壓電的用方波,才能有較好的聲音輸出.
尺寸: 蜂鳴器的尺寸會影響到音量的大小,頻率的高低,電磁式的最小從7mm到最大的25mm,壓電式的從12mm到50mm或更大都有.
連接方式: 一般常見的有插針(DIP), 焊線(Wire), 貼片(SMD), 壓電式大顆的還有鎖螺絲的方式.
音壓: 蜂鳴器常以10cm的距離做為測試的標準,距離增加一倍,大概會衰減6dB, 反之距離縮短一倍則會增加6dB,電磁式蜂鳴器大約能達到85dB / 10cm的水準,壓電式的就可以做的很大聲,常見的警報器,大都是以壓電蜂鳴器製成.
以苙翔的料號, 用量最大的電磁式蜂鳴器AC-1205G為例
A = AATC
C = 一體式,底部有封環氧樹脂的蜂鳴器, 另有AS = 分體式,底部沒封膠,一般頻率為2000左右,不可過錫爐. AX表內含驅動線路(自激式).AD表SMD的.
12 = 直徑,單位是mm, 還有6.7, 9.0, 9.6, 14, 16, 25mm的,並有多種高度選擇
05 = 額定工作電壓, 還有1.5, 3.0, 3.5, 5, 6, 9, 12, 24V.
G = 直流阻抗
壓電式的以AZ-1440S-P為例
A = AATC 苙翔科技
Z = Piezo 壓電式蜂鳴器
14 = 直徑, 10, 12, 14, 16, 17,.....50規格非常多.
40 = 額定的頻率, 40表4KHz,
S = Self drive 自激式,內含線路的, E 表他激, 外部驅動.
P = Pin type, 還有W- Wire, APD-SMD的

Design guide of Microphone Array 麥克風陣列的機構設計

Microphone Array

The position of the microphones should be set far away from the source of noise which comes from the product itself, such as fans, keyboards, speakers, or CD-ROM drives, etc. Besides, the microphones are requested to aim at the user, and should be as close to them as possible.
麥克風的位置應遠離產品本身的的噪音源,如風扇,鍵盤,喇叭,光碟機...
並盡可能的對準,接近使用者.

Considering the space of the mechanism design, there are two methods to install the microphones:
1. The stacking typeWhen the microphone array is consisted of an omnidirectional microphone and a unidirectional one, the position of the main sound hole should be set in the middle of the two microphones. Then another secondary sound hole is requested to set for the rear vent of the unidirectional microphone to receive sound.
考慮機構上設計的空間問題,有以下二種裝置方式,
1. 堆疊式
當使用的是一個全指向麥克風配一個單指向麥克風時,主音孔的位置要在二個麥克風的中間,
另需一個副音孔,供單指向麥克風的後氣孔收音用.

2. The side by side type
The two microphones should be set as close to each other as possible, or use one sound hole. Besides, the rear vent of the unidirectional microphone also needs to keep unobstructed in order to receive the sound.
2. 並列式
二個麥克風應盡可能的靠近,或合用一個音孔,單指向麥克風的後氣孔也需保持通暢,能收到音,

Is the more sensitive microphone the better? 麥克風的靈敏度愈高愈好嗎?

The sensitivity of the microphone is one of the most important factors, which affects the receiving result. The higher the sensitivity is, the higher the SPL can be received.Different from the production process of other products, the microphone is selected and sorted by its sensitivity after producing. We cannot get 1000pcs of what we need in sensitivity from just inputting 1000pcs of microphones’ material on the production line. Therefore, in order to avoid discontinuing the production, we had better choose the spec. usually with the sensitivity of -40 to -44, which is popular and easily produced.About the volume, we can still improve it by modifying the circuit, such as the impedance, the voltage, and the amplification factor.We suggest that do not choose a special spec. with very high or low sensitivity at first, or the problem of lead time and lacking of material might happen.
麥克風的靈敏度是影響到收音效果的重要因素之一,靈敏度愈高,所能收到的音量也說愈大,
但因為麥克風的在生產完之後,再根據實際的靈敏度值加以挑選分類,
並不是投料1000pcs就能做出1000pcs所想要的靈敏度,而會呈現常態的分布,
故最好挑選一般常用,好生產的靈敏度,如-40到-44,在大量使用時,比較不會有斷貨的可能,
而最後的音量問題,仍可藉由線路上的修改,如電阻的大小,電壓大小,放大倍率...來解決,
千萬不要一開始就挑選特別高或特別低的麥克風規格,以免陷入交期交,或缺料的問題中.

The reason why the speaker emit noise喇叭產生異音的原因

To analyze the usage, there are a few reasons explain why the speakers emit buzz sound or noise:1. Speaker is a passive component, and the drive circuit decides the sound. Therefore, giving the correct power and waveform to the speaker is the basic request.The too large power will lead to the too big amplitude of the diaphragm. The slight problem is distortion, but the serious problem is that the diaphragm might hit the mechanism or the magnet and cause the buzz sound. The basic waveform to drive the speaker is sine wave, if we give square wave or other waves, the efficiency of the speaker will reduce and easily get heated, the buzz sound may happen as a matter of course.
2. The enclosure design of the product will also affect the quality of the sound. The well designed enclosure can improve the frequency response curve of the speaker.The area of sound apertures of the enclosure at least request over 1/8 area of the surface. We need to keep enough vibration space between the case and the diaphragm to avoid the diaphragm hitting the case when it works and emits the noise.
喇叭發生破音/異音的原因,從使用者的使用上的原因來分析,有以下常見的問題,
喇叭是屬於被動元件,會發出什麼聲音是由喇叭的驅動線路決定的,給予喇叭正確的功率,波形是最基本的要求,
過大的功率會造成膜片振幅過大,輕微的會有失真的問題,嚴重的話會振膜會打到機構或是磁鐵,就造成了破音,
驅動喇叭基本波形是弦波,若給予方波等其他波形,喇叭的效率會變低且容易發熱,同時也可能產生破音,
產品機構的音箱設計也會到喇叭的音質,適當的音箱可以改善喇叭的響應曲線,
喇叭出音孔最好有1/8以上的開孔率,且機殼與振膜之間要留膜片振動的空間,以免在發聲時撞到機殼而產生異音,

The advantages of the Microphone Array 麥克風陣列的優點.

With the constant enlargement of the internet bandwidth, the internet video conference has become possible. However, the wide bandwidth does not mean high quality of sound. The consumers usually need to wear the earphones to get the clear sound effects, and it is really inconvenient for them. Therefore, VISTA has already started to support the function of microphone array, which help to record sound more clearly, and can eliminate the noise and wind shear sound in the background. Naturally, besides the support of the operating system, the computer hardware also needs to be matched. Consequently, with the collocation of the microphone array and the DSP, the consumers can easily enjoy using the web phone such as SKYPE without wearing the headsets.
隨著網路頻寬的不斷擴大,使網路上的視訊會議變的可行,
但頻寬夠並不代表聲音的品質就好,消費者常需要佩戴上耳機,才能有清晰的音效,
而這是消費者覺的很麻煩的事,故VISTA已開始支援麥克風陣列的功能,
可使收音的效果更清晰,可消除大部份的背景雜音或風切聲,
當然除了作業系統的支援,硬體上也需配合,故就需要麥克風陣列再加上DSP的搭配,
就可讓消費者再也不用戴耳機,也可以輕鬆的使用SKYPE之類的網路電話功能.

The theory of the microphone array is to set more than two pieces of microphones to record the sound separately, and than the DSP will pick the tonic we want. The simplest design is to pair a unidirectional microphone and an Omni directional one, which can limit the sound receiving range at the width of 120-140 degrees in front of the microphone, and then the SPL will be reduced over 20dB beyond this conical area. This is the reason why the ambient noises can be reduced widely and hardly to be heard.
其原理就是用二顆以上的麥克風,分別收錄聲音,再用DSP加以處理,取出想要的主音源,
最簡單的設計就是以一個單指向的麥克風,,配上另一個全指向的麥克風,
就可以將收音的角度限制在使用的正面約120-140的角度內的圓錐體內,
在此圓錐體之外的音壓會衰減達20dB以上,這就使環境噪音被衰減到幾乎聽不到的程度,
關於設計上的問題,請參考: 麥克風陣列機構設計

The key point of soldering and assembling the microphone 麥克風焊接組裝注意事項

Soldering manufactureThe diaphragm of the microphone is a very thin mylar membrane, it is easily being contracted and distorted with the high temperature. Therefore, we can only use hand-welded method to process, and the temperature of soldering iron cannot over 330°C, the welding work should be done within 2 seconds, the faster the better.The best way is arranging the skilled welders to solder one wire/ pin first, and then finish the left one after the microphone cool down, this can avoid the high temperature causing distortion of the diaphragm, the worse sound receiving results or even breaking down.Otherwise, you can entrust the manufacture to us, our factory has special manufacturing tools to help the microphone cool down. Besides, we will test the sensitivity again after soldering in order to keep the qualification and the reliable quality.
焊接加工
麥克風的振動膜是很薄的塑膠膜,易受高熱影響而收縮變形,
故只能以手焊的方式加工,且烙鐵的溫度不可過高(330度C內),焊接時間需在2秒內,焊接時間愈短愈好,
最好安排請熟綀工焊完一條線(或pin)後,間隔一段時間,待麥克風冷卻後再焊另一條線,
以免過熱使膜片變形,收音效果變差,甚至壞掉.
或可委由我們加工,工廠有專用的製具,可幫助散熱,並會在焊完後再測一次靈敏度是否合格,以確保品質穩定,
Assembling manufacturingThe microphone itself need to aim at the sound hole of the mechanism case, and being as close to the surface of the case as possible in order to gain the best receiving results.Trying to use rubber holder to separate the outside noise, especially the wires type assembling method can do good to fix the microphone on the case of the mechanism.
組裝加工
麥克風本體要對準機殼的音孔,並盡可能的貼近機殼表面,以獲得最好的收音效果,
盡量使用Rubber holder來阻隔外部雜音,尤其是焊線式的組裝方式,也更容易牢靠的裝在機殼上,
When we fabricate the microphone, no matter adding rubber holder or not,
microphone should be pushed to the bottom of the mechanism,
to avoid a chamber forming in front of the sound hole and affecting the sound which microphone receives.
組裝麥克風時,不論有無橡膠套,麥克風都應該要裝到機構的最底部,
以避免形成音腔,而影響麥克風的收音效果.

The interpretation of specification: Watt, Decibel, Hertz, and Resonance

W ( Watt ): A watt = a voltage x an ampere. For example, 330 Watt= 110V x 3 A.
V ( Volt ): V is the unit of voltage, when it needs one joule of work to sent one coulomb of electric from one point to another point, then the potential difference between these two points is one voltage. 
Ohm: Ohm is the unit of impedance in electronics, the higher the impedance is, the less electric current can pass through. 
Hz( Hertz): The frequency of the sound waves vibrate every second. For instance, 100Hz means 100 times vibration in one second. 
dB ( Decibel): dB is the unit of the sound pressure level, which is calculated with logarithm, because the susceptibility to the sound of human ears is not linear. 
Fo ( Resonance Frequency): Fo stands for the resonance point of the speaker. The lower the Fo is, the efficiency of the low frequency is better. 
S.P.L. ( Sound Pressure Level): The volume of the sound. 
Vo-p: The measurement from Vo to the peak, to drive the magnetic buzzer, the waveform is 1/2 square wave. 
Vp-p: The measurement from peak to peak, to drive the piezo buzzer. The waveform is square wave.
W (Watt) :瓦特, 一瓦特= 一伏特的電壓X一安培的電流, 330 Watt= 110V X 3 A.
V (Voltage): 伏特,表示電壓的單位,將一庫侖電荷由一點送到另一點，若須作一焦耳的功，則稱二點間之電位差為一伏特.
ohm : 歐姆,表示電子學上電阻阻抗的單位,阻抗愈高,能通過的電流愈少.
Hz (Hertz): 赫茲,波在每秒振動的次數, 100Hz = 一秒振動100次.
dB (deciBel) : 分貝, 表示音量大小的單位,是以對數算出來的,因為人耳對聲音的敏感度不是線性的.
Fo (Resonance Frequency) : 共振,用來表示喇叭的諧振點,頻率愈低,喇叭低頻的效果會愈好.
S.P.L. (Soudn Presure Level): 音壓位準,即音壓的大小值.
V0-p : 電壓從0V到峰值,用來驅動電磁式蜂鳴器, 波形為1/2方波.
Vp-p: 電壓的峰對峰值,,常用以驅動壓電式蜂鳴器,表示為方波的波形,

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.

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.

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.

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!!

The difference between the self drive and external drive buzzers

The difference between the self drive and external drive buzzersDepend on the driving signal, the buzzer divide into self drive and external drive. However inner circuit/ no circuit, DC/ AC, and active/ passive are all mean the same.
The design of the self drive buzzer is to set the circuit inside the buzzer and just offer the direct current to work. The inner circuit has the designed frequency and voltage for the buzzer to generate sound, therefore the frequency of the self drive buzzer is fixed. However the frequency is still different from each buzzer, normally is 2300Hz, the acceptable range is +/-300Hz.
However, the external drive buzzer needs to be drove by the signal of 1/2 square wave V 0-p (magnetic type), or square wave V p-p (piezo buzzer)
It is convenient to use a self drive buzzer, but the disadvantages are the higher cost, the higher defective rate and the unchangeable frequency.

依照驅動信號的不同,蜂鳴器分為自激式及他激式二類,有很多不同說法,但指的都是這二種分類,
如:內含(不含)線路,直流DC/交流AC Type, 有源(無源),
自激式的蜂鳴器是將驅動線路直接設計到蜂鳴器中,故只需給予直流電壓,
內含的驅動線路,就會產生設計好的頻率及電壓給蜂鳴器發聲,所以自激式的頻率是固定的.
但每顆蜂鳴器間的頻率仍會有些差異,一般常見的是2300Hz, 頻率上下300Hz都算可接受的範圍,
而他激的蜂鳴器,需由外部線路給予1/2方波V 0-p(電磁式),或方波Vp-p(壓電式)的信號,才會發聲,
在使用上用自激式的蜂鳴器有其方便的地方,但因為成本及不良率較高,且頻率不可調整,

Introducing the enclosure of speaker 喇叭音箱介紹

Reflex Enclosure 反射式音箱：
It is the most popular design. When the diaphragm of the speaker generates sound, the sound waves which are reflexed from the rear board will be sent out by the reflex pipes. The size and length of the reflex holes and pipes all affect the extension of low frequency, therefore according to the character of the speaker, we should design proper holes and pipes in order to get the best speed and the extension of low frequency.
為最多的設計方式。當單體振膜發聲時，其聲音打到後板所反彈的聲波，藉由反射導管將反相的聲波傳遞出來。其反射孔的大小與導管的長度皆會影響低頻的延伸，因此必須根據單體的特性，設計出適合的孔徑與導管的長度，以取得最佳的速度感與良好的低頻延伸。
Closed Enclosure 密閉式音箱：
The enclosure is entirely sealed. This design will decrease the operating efficiency even though the low frequent voice is good. Therefore in order to get better control, we must give high power to operate it or the speed of the low frequency will be delayed.
其音箱完全採密閉式，雖然能獲得不錯的低頻音色 設計方式會大大降低喇叭的效率，若要獲得良好的控制力，就必須採用超大功率來推用，否則其低頻的速度感會有遲頓的現象。
Passive Radiator Enclosure 背輻式音箱：
A kind of closed enclosure, mainly adds another low frequent speaker. When it vibrates to generate sound, the passive radiator diaphragm is pushed by air. The disadvantage is low efficiency and speed.
屬於密閉式音箱，主要多增加一支只有振膜的單體(低音單體，當低音振動發聲時，其藉由空氣來推動背輻式振膜的延伸。但有效率低及速度慢的缺點。
Isobaric Type Enclosure 等壓式音箱：
It is able to increase the low frequent energy, but the closed design causes the low efficiency. When the two speakers work at the same time, if the sound is out of phase, it affects the results as well.
能增加低頻的能量，但密閉式的設計會造成效率較低,兩支單體同時發聲時，若聲音有不同步的問題產生，也會影響喇叭的暫態反應。
Transmission Line Enclosure 傳輸式音箱：
The transmission line enclosure extends the low frequency by a long wave guide; however the over-length of the wave guide may lower the speed of the low frequency.
藉由較長的傳輸管道來增加低頻的延伸，但過長的管道會導致低頻速度慢。

The structure of specialized enclosure 專業用音箱結構：
Reflex Enclosure 反射式音箱：
The design principle is the same as household reflex enclosure.
其設計原理同家用的反射式音箱。
Horn type Enclosure 號角式音箱：
Because of the good diffusivity characteristic of the horn type enclosure, the low-pitched sound is extruded first then sent by the horn to the far place. At the outdoor concert, it is difficult to send the normal low frequency, therefore, we need to use the horn type enclosure to extrude the low frequency and send it. The disadvantage is the worse low frequency extend.
利用號角擴散性佳的特色，先將低音予以擠壓，再經由號角的擺盪，能將聲音傳送較遠處。在戶外大型的演唱會上，一般的低頻並無法傳送較遠處，因此必須藉由號角的擠壓將低頻傳送出去低音。 缺點為低頻延伸較差。
The enclosures we introduced above can not be completely applied in all the electronic products, it is for consultation; we need to face and solve more problems in reality.但是,以上介紹卻無法完全應用在現在電子產品上,只能參考與活用,原因已經在上述說明,且小speaker參數必須用實際搭配來試,現實問題較多.

The way to drive a buzzer 蜂鳴器的驅動方式

For a self- drive buzzer ( DC/ circuit- built), either pizeo or magnetic just apply the rated current and voltage.
 For the external-drive buzzer, it depends on,
1. We should give magnetic buzzer 1/2 square wave, and provide it at least 3 times the amount of the rated consumptive current.
2. Otherwise, we give square wave to the peizo buzzer instead of 1/2 square wave, because the half wave might cause the buzzer does not work.
Therefore, voltage control is an important factor for a peizo buzzer which is driven by the voltage.

若是自激式Self-drive (DC/內含線路circuit-bulit in )的蜂鳴器,不管是電磁,還是壓電的,給予額定的電流及電壓即可,
而外激式External的蜂鳴器,因為工作原理的不同,)
電磁式蜂鳴器(Magnetic Buzzer)應給予1/2方波(square wave),及在啟動時,確保至少有三倍於額定消耗電流的電流,
壓電式蜂鳴器(Piezo Buzzer)的則給予方波, 若給1/2方波,極可能不會動作,因為只有半週的動作,
由於壓電式蜂鳴器,是靠電壓驅動,電壓的控制是重要的因素.

The sound which microphone received is too low 麥克風收到的聲音太小

There are three reason might cause the problems,
1. Lower sensitivity of microphone
The sensitivity of the condenser microphone is from -36 dB to -48 dB (0dB= 1V/Pa). If we use -44 dB microphones, the sound will be lower.
2. Defective design of amplifier
The impedance for the amplifier will affect the sensitivity and the frequency response.
Normally, the higher the impedance is, the better the sensitivity will be. However if the impedance is too high to get enough voltage/current, the high frequency response may get worse.
The lower the impedance is, the lower the SPL will be. The too much current will cause the insufficient voltage.
Input higher voltage will increase the sensitivity. Depend on the design of the amplifier and the frequency, the sensitivity might increases around 0.3 dB to 0.6 dB by 1 V.
3. Defective design of mechanism
The over-length or curved sound receiving holes leads to lower or unnatural sound.
麥克風所收到的音量太小,主要來自於三種原因,
1. 麥克風的靈敏度偏低
電容式麥克風的靈敏度大概介於-36 ~ -48dB之間(0dB=1V/Pa),若採用-44dB的麥克風,則可能收音的聲音會較小,
2. 放大線路設計不良
放大線路所匹配的阻抗,會影響麥克風的靈敏及高低頻的響應,
一般來說,匹配的阻抗愈高,麥麥克風的音量會愈大,但阻抗高到造成給麥克風的電壓/電流不足時,高頻的響應會變差.
阻抗愈低音量愈低,因為電流量太高使電壓不足.
給麥克風的電壓愈高,靈敏度也會增高,增加1V大約是0.3-0.6dB左右(視放大線路設計,頻率有所不同)
3. 機構設計不良
收音孔太長,或是彎曲,都會使收到的聲音變小或不自然,