The factors which affect the SPL: the square measure of diaphragm, the amplitude of vibration, magnetic field intensity, power, impedance, resonant chamber, the pattern and the thickness of diaphragm, and the holes.
Power vs. SPL: Suppose all the conditions are the same, increasing the power dose not mean the SPL will increase as well. We need to revise the diaphragm and the sound coil to load the higher power, but it leads to lower SPL instead.
Dimension vs. SPL: A larger speaker can vibrate more air, therefore it provides higher SPL. In addition, the thicker speaker can give wider amplitude of vibration which also leads to higher SPL.
Acoustics: What we request most is how much SPL a micro speaker can output.
Matching: It will be better to provide the power slight higher than the rated power for the enlarged circuit.

音量 會影響聲音大小的因素: 膜片面積,振幅,磁場強度,功率,阻抗,音腔大小,膜片花紋/厚度,開孔.
功率VS.音量 在相同條件下,功率加大不表示音量會同步增加.因膜片及音圈改變,在同樣的輸入信號下,有時音量反而會更小.
尺寸VS.音量 愈大的尺寸,在同一時間能振動的空氣愈多,故音量一定會愈大,喇叭的厚度愈厚,通常意味著有比較大的振幅,聲音也會大些.
音質 小喇叭基本上是不討論音質,而是要盡量把音量做高.
匹配 放大線路的功率最好稍大於喇叭的額定功率會較好.

The volume of the resonant chamber: The general problem of the consuming products is that the resonant chambers are not big enough. We can only try to find space to enlarge the volume of the resonant chamber.
Sound Hole: Must be more than 1/8 of the diaphragm’s area at least.
Airtight: The front and back sound fields of the speaker should be separated to avoid neutralization.
Shock absorber: When a speaker works the vibration will also happen at the same time. In order to reduce interference, it will do good to have some material between speaker and case to absorb the shock.
Mounting: The speakers are usually fixed on the case. Firmly fixed is important especially for the iron housing or the large size to avoid separating in the drop test.
音腔大小 在消費性產品上,普遍都有音腔不夠大的問題,只能盡量找出有空的地方,增加音腔的容積.
開孔率 至少要有膜片面積的1/8以上
氣密 喇叭的前後音場要完全隔開,以免相互抵消,
避震 因喇叭發聲的同時也會產生振動,與機殼間最好有緩衝材料,以免產生雜音.
固定 喇叭常固定於機殼上,需注意牢靠度,尤其是鐵殼或較大尺寸的,以免落下試驗時脫落.