The relationship between Watt and SPL 瓦數愈大喇叭會愈大聲嗎?

Base on the premise that all the conditions are the same, if the drive circuit provides enough voltage, the speaker can generate higher sound pressure level. However, with the same voltage, but we use another speaker which applies higher rated power, it will be difficult to drive and output lower sound pressure level.
For example, a circuit can only provide the power of 8 ohm 1 W, in order to generate higher sound pressure level we collocate a 2W speaker, the SPL will be lower instead of higher. It is because with the increasing of the power, the diaphragm should be thickened. The coil also needs to be replaced by thicker wires. However, the thicker wires results in lower impedance so we have to wind a bit longer more, and that makes the coil heavier than before. Oppositely, if we use another speaker which loads lower power or with lower impedance, it is likely to make a little bit higher SPL, however the noise or burning down will possibly happen in this condition.
在所有條件一樣的前提,如果驅動線路提供足供電壓,喇叭的聲音是會比較大,
但如果驅動線路所能提供的電壓還是一樣,那換上額定功率愈大的喇叭,
就會發生所謂推不動的狀況,聲音反而會更小,
例如,線路只能發出8ohm 1W的功率,想要更大聲而換用2W的喇叭,反而會小聲,
因為隨著設計功率的加大,喇叭的振膜需要加厚,音圈也可能要換更粗的線,
更粗的線阻抗會降低,只好多繞長一點,音圈的質量就更重,
這些改變會使喇叭效率變差,也就是我們說的變小聲了,
反之如果我們換用承受功率小一點或是阻抗低一點的喇叭,
有可能會大聲一點,但要小心喇叭不會有破音,甚至燒毀的情形發生.