Default standard for speaker "sensitivity" measurement listings? Anechoic? In-room? Other?


I’m researching speakers which will play nice with tube amps.

I recognize that a number of factors are at play, not least sensitivity and  impedance. Too low an impedance dip and/or too many wild swings in the graph and they tube amps may find driving the speakers a challenge.

So...some companies list BOTH in-room and anechoic sensitivity for speakers. Others just say "sensitivity."

QUESTION: When a company ONLY lists “sensitivity” is it understood to mean in-room or anechoic? Or something else? Or is there no standard one can assume?

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When I look at the measurements on the Salk site, none of them show anything below 200 hz. He may well be using a measurement method something like lonemountain describes. That is to take nothing away from his speakers, because I have found them to sound very good every time I have heard them.

Jim Salk told me his measurements were anechoic because in room measurements are meaningless.

Except that is where we all end up listening to their products.

That's why in room measurements are meaningless to a manufacturer unless every room was like the one they were measured in. 

Except that is where we all end up listening to their products.

 

I totally get Jim Salk's point; it's valid to insist on a metric which can be compared to other identical metrics. The question I would raise is the "half space" measurement equivalent, technically, to the anechoic one? Otherwise, instead of the apples-to-oranges problem (of anechoic to in-room) we have an apple-to-pears problems (of anechoic to half space).

Jim Salk might have built his own "anechoic room".  Some passionate engineers do exactly that, build one in their office or their warehouse or factory.  They are not necessarily true anechoic, as that is very expensive, but it can give you an idea.  This can yield good info but with limitations.  One of the most critical things in a true anechoic environment is noise floor.  If there is any noise leaking in, say HVAC, a truck driving by, wind around the building, it will screw up your measurements.  So if you built a chamber in your office, you'd turn everything off when you measure.  The fact that he states measurements only down to 200Hz is admirable though, as 200Hz would represent 5 or 6 feet dimension- whihc sounds like it clould have been a custom built chamber.  The other possible reason for the 200Hz is the measurement microphone being used to measure, which may not have had reliable flat response below 200.   

Here again,  MUCH we dont know about how it was measured, which makes the measurement relaible only in comparing his speakers to each other.  His measurements are not useful in comparing them to other brands, which would have been measured differently unless it was done in HIS chamber using HIS system.

This is the problem with specs: many many ways to affect results that make them  not comparable to anyone elses measurements.   Its like saying your table is  "brown", its not an absolute and is not translatable - there are 1,000's of different browns.  

Brad