Audio Systems/speaker spl

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Expert: - 3/29/2009


Question
Hi if a speaker is 90db @1watt/1meter what would it be at 1watt/2meters?

Answer
In open space the spl drops 6db each doubling of the distance.

So at two meters it would drop to 84db.

In the home or car where there are reflections of all kinds the loss is less, depending on the reflection coefficients.  But in several acoustic tests conducted over the years it was found that in normally furnished rooms the drop we close to 3db when distance is doubled.

It is also level and program material dependent to some smaller degree.


Here is a reference:

http://irc.nrc-cnrc.gc.ca/pubs/fulltext/nrcc36983.pdf

Here is a reference for out-of-doors tests:

http://military.technomad.com/products/range-spl-table/

Hope you find this as interesting as I do!

C  

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Cleggsan

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Audio Design Engineer; systems, loudspeakers, cd/dvd players, etc. I am knowledgeable in all high end audio equipment and installations. MAKE SURE YOU GIVE A MAKE AND MODEL NUMBER AND CAR IF IT IS AN AUTO QUESTION. Note: I am getting some who ask good questions that take a lot of time to research but then the questioner fails to read the answer. Please don't ask questions unless you are seriously looking for an answer. If you find an answer to your question otherwise then let me know with your reply. Thank you.

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Have been associated with audio design, standards, testing and component systems for over 40 years.

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Review technical manuscripts for IEEE Spectrum Write occasionally for high-end audio publications

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Past Employee/advisor to several well known audio products manufacturers

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