speaker effiency

"Efficiency" is commonly mistaken for "sensitivity", as shown by the above poster. Efficiency is expressed in percent, representing how much electrical energy is converted into acoustic output. Both above postings are concerned with sensitivity, which is usually expressed as dB of output measured at 1M from a particular point of the source, with 1 watt input. This is complex, as different measuring points for the pick-up microphone will produce different results. Also the source's radiation pattern affects its rate of attenuation as a function of distance. The difference in output could be attributable to mistaken manufacturer specifications or a result of the 4 ohm speaker drawing twice the voltage of the 8 ohm speaker, or both. The question of whether or not the sub will match output is best answered by trying it out.

Correction on my last post, second to last sentence: replace "voltage" with "current"; duh...sorry.

I, being the lovable audiophile with some degree of Scotch-Filipino temper to control, will do my best to keep this all civil. Will forward reply from Galen Carol (ex-JBL factory speaker driver techcician) upon receipt. There are eight Stereo Review/Sound & Vision Equipment Directories nearby going back to 1980 (twenty years ago) that agree with me & the secretary of the local Acoustical Engineering Society, & disagree with the above posters & (at least partially, keep reading) the Vandersteen website's useage of the term "efficiency". Here is the response from Brian Cheney, sec. of the local AES: "Sensitivity is measured in dB SPL per W input at distance. Efficiency is the ratio of acoustic output to electrical input. Low efficiency might be around 1%, high efficiency around 5%. Vandersteen is being sloppy. B" Here is the summary of my phone conversation with Richard Vandersteen this morning: Richard admitted to me that he has never seen efficiency measured in percent, & that he only started in the business in the mid-'70's. This is consistent with my earlier post that "effficiency" has fallen into more recent misuse. When he was told of the "classical definition" & "unit of measure for efficiency", he admitted he "may be wrong". He is wrong, as are the above posters. He also said he would not charge customers a "2%" surcharge just to fix all the literature. He got snippity & used the term "bullshit". I proposed changing the website. You will have a hard time finding another speaker company using "efficiency" the way he does because I know of none, & I do a lot of reading on this subject. It will take a little more weight than one speaker company & website posters to change it's accurate technical meaning. I use the following information to further impeach Mr. Vandersteen: am I the only one who notices a lot of photos of boxes next to the word "boxless" describing Vandersteen's products? Does "boxless" mean the same as "box", or is Richard just generally careless with his website content? He also admitted that sensitivity is misleading & that it gives the customer little to no indication of output, which means he is presenting misleading information to readers. Also, I know none of the above posters have seen efficiency units as percent, but no one has presented evidence contradicting my above proof that there is such a thing as an audio definition relative to speakers which is: the percent or ratio if acoustic output to electrical input. I propose the term for which this is a definition is "efficiency". If you disagree, what is the term for which this is a definition? Jim Romeyn, Petaluma CA

Glad I caught this b4 the flames arrived: insert "Audio Engineering Society" in place of "Acoustical Engineering Society". Whew! Thanks. Jim

A light when on when you first mentioned Vandersteen. I remembered in the early '80's seeing Vandersteen use "efficiency" incorectly. "Efficiency" (measured in percent) was, as I said, fairly commonly used in the early days with lower-output tube amps & high sensitivity speakers. This was later inverted. Solid state made watts cheaper, so speaker designers had the freedom to make lower-sensitivity speakers. "Sensitivity" became the term of choice. But the true original meaning of efficiency & its unit of measure (percent) has never changed. Since then people have come along unfamiliar with it. Peace. Jim