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<blockquote data-quote="bdavies11" data-source="post: 2934845" data-attributes="member: 563458"><a href="http://www.epanorama.net/documents/audio/speaker_impedance.html" target="_blank">http://www.epanorama.net/documents/audio/speaker_impedance.html</a>Impedance and effiencyLet&#039;s look at the following situation: Take an 8 ohm speaker and wind twice the length of wire onto the voice coil. The resistance woul go up, for sure, but because there is no more wire in thegap, the electromagnetic couping coefficient, the Bl product, would also go up. And you would have, as a result, a 16 ohm speaker with essentially the same efficiency as the 8 ohm speaker, all other things being equal.Or you could design a speaker with both a higher impedance (longer wire in the voice coil) AND a larger magnet assembly with higher flux density in the gap and get a higher impedance driver with higher electro-acoustic efficiency.Or you could design a higher impedance driver with a stronger magnet and a lighter cone and get even more efficiency.The point is, the rated impedance IS NOT the same as the efficiency, nor is there any direct correlation between the two. Efficiency of a given direct readiator driver is determined by the folowing relationship: l</blockquote>

[QUOTE="bdavies11, post: 2934845, member: 563458"] [URL="http://www.epanorama.net/documents/audio/speaker_impedance.html"]http://www.epanorama.net/documents/audio/speaker_impedance.html[/URL] Impedance and effiency Let's look at the following situation: Take an 8 ohm speaker and wind twice the length of wire onto the voice coil. The resistance woul go up, for sure, but because there is no more wire in thegap, the electromagnetic couping coefficient, the Bl product, would also go up. And you would have, as a result, a 16 ohm speaker with essentially the same efficiency as the 8 ohm speaker, all other things being equal. Or you could design a speaker with both a higher impedance (longer wire in the voice coil) AND a larger magnet assembly with higher flux density in the gap and get a higher impedance driver with higher electro-acoustic efficiency. Or you could design a higher impedance driver with a stronger magnet and a lighter cone and get even more efficiency. The point is, the rated impedance IS NOT the same as the efficiency, nor is there any direct correlation between the two. Efficiency of a given direct readiator driver is determined by the folowing relationship: l [/QUOTE]

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