speaker effiency

Spkrplus, ok, what is it? Vandersteen says efficiency is measured in db/watt and Theil specs sensitivity in db/watt. I never saw any specs in terms of percent.

tend to agree more with Gmkowal

Efficiency is almost never (correctly) used anymore. It's useage in general has become less common since approximately the late 1960's. I know useage determines definition, but this is something serious students of the loudspeaker art & science would defend steadfastly, & the differences are worth noting. Sound & Vision Buyer's Guide 2001 (Glossary page 338) defines "efficiency" as "The percentage of electrical input power going to a speaker that is converted into acoustic energy; often used synonomously with the related concept of sensitivity." Not "is a synonym", and not "always interchangeable with", but rather "used synonmously". A girlfriend who has performed "wifely" functions can not successfully sue for divorce. Also it does not say "identical concept" or "same concept", but rather "related concept". The measurement units "percent" & "dB/watt/meter" are not always interchangeable, & not in this case. In this case "percent" expresses how much of an amplifier's power is converted into acoustic energy, while "dB/watt/meter" expresses a specific unit of sound pressure measured at a particular distance from the source with a specific measure of power applied. For instance 87% can not be compared to 87dB/watt/meter for (I hope) obvious reasons. In the former, 13% of the applied power is not converted into acoustic energy, whereas in the later, that percentage is unknown & undecipherable (form the information given, anyway). I respectfully request poster Gm to list the specific Vandersteen literature mentioned. Richard V. or anyone in his tech. dept. would agree with me & Sound & Vision. Likely the copy, if published by Richard's company, was written by an ad person who does not even know what absolute polarity is. Other reliable sources would be Brian Cheney, the San Francisco Bay Area Chapter secretary of the Audio Engineering Society ([email protected]) or Galen Carol at Galen Carol Audio, who was in the technical dept. at JBL when it was known as James B. Lansing Co. If this all seems too trivial, I apologize, but as the great Jack Webb used to say, "Just the facts, m'am. Just the facts". This is a good thing about which hobbyists should know & agree upon the differences. Cheers.

Go to the Vandersteen website and look at any of their speakers specs.

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