請教一下,搞成這樣除了音量比較大外,有其他的好處嗎?
不過看起來就蠻嚇人的
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有點長但是解釋得很好
Increase of sensitivity due to lower resistance
Each time the resistivity halves (i.e. goes from 8 ohm to 4 ohm, etc.), the sensitivity doubles, and quite vice versa. So, when connecting two 8-ohm speakers in parallel, the impedance drops to 4 ohm and the sensitivity increases 3dB because the amplifier develops more power into the lower impedance. If you would connect the two drivers in series, the impedance increases to 16 ohm. Ignoring for a moment the cone-area increase's effect, the sensitivity will drop 3dB because the amplifier produces less power into the higher impedance.
This is based on the following principle: when the impedance halves, the amplifier doubles it's output power, and hence the 3dB rise in output level. In a solid-state amp this works, but what about the valve amp. Their spec.sheet usually indicates the same power into 4, 8 or 16 ohms. So they do not add the 3dB increase.
Increase of sensitivity due to enlarged cone area
For each doubling of the cone area, the sensitivity rises 3dB, i.e. if you have one cone, adding a second one will add 3dB to the sensitivity (ignoring for the moment changes of impedance). Now with two cones, Sd must be doubled (total four cones) to add another 3dB to the sensitivity. To increase the sensitivity another 3dB, you need to add four cones, etc. ad infinitum.
<img src='http://yu-ra.tripod.com/audio/multi.jpg' border=0>
小氣音響一族