Originally Posted by KidHorn
In theory, you're right, but people who have done actual measurements rarely see it work that simply. The issue is doubling the power of a receiver does not mean a speaker will convert all of this to sound. Some of the power goes to heat and other things. So, on paper, in a 100% efficient system, doubling the power equals a 3DB increase, but since nothing is 100% efficient, in reality this never happens.
Not sure regarding the perfection of your above but we all can agree that the 3dB standard is the accepted standard of the home AVR set as we don't all have or know how to use test scopes. My take, the 3dB standard is just that, a generalized standard we all can work from, just like when buying a loan the buyer of the loan has two numbers to work with. The first number is the actual mortgage or loan rate and the second number, the APR, is a simplified way of telling the loan purchaser what all the fees work out to when amortized over the life of the loan. Other examples would be the lab sensitivity rating of a speaker or the stated power output of a receiver when compared to real world use of measurements in an open room at four meters or all channels driven to 1% THD. In the case of my speakers, although rated a 100dB 1w/1m, a more realistic rating would be 86dB 1w/4m and although my AVR is rated at 100w, when five channels are driven to 1% THD, the output is more like 89w.
In my above, I'm agreeing with you as I compare the world of the ideal (lab measurements) vs measurements one can expect to obtain in real world settings; our home theater room, at the main listening position, Audyssey has been run and the AVR volume control set to 0dB. Please pass the popcorn.
Last night's real world movie choice was a cable box provided, DD movie soundtrack: "The Debt." An excellent (although typically slow at times) 60's, cold war style movie set in 1965 East/West Berlin, juxtapositioned on top of the present day lives of four personalities. A solid movie of intrigue, deserving a five out of five popcorn bag rating.
-Edited by BeeMan458 - 10/5/12 at 7:46am