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<blockquote data-quote="Mark DeArman" data-source="post: 137947" data-attributes="member: 950">Re: dB calculationsMany manufacturers provide a sensitivity plot vs. Frequency for boxes or OEM speakers using a reputable piece of test equipment, not a Averaging SPL meter.&nbsp; And probably 75% of manufacturers at least measure the sensitivity with the proper tool and only report the one &#039;peak&#039; number. This is exactly what we have been talking about in this thread. The whole idea behind a Averaging SPL meter, is measurement of uncorrelated noise signal.&nbsp; Like you said, the most common use of these devices is compliance testing for local and federal laws.&nbsp; These devices were not designed for measuring anything about a loudspeaker(s) and no professional really does use them that way, except to make sure their show is complying with the local laws.It is easy when looking at definitions online, to just read past a statement like, &quot;uncorrelated noise,&quot; and assume that the math might still work out.&nbsp; It just doesn&#039;t work out; no more than playing pink-noise through a speaker, taking the FFT, and assuming that what you see is the frequency response of the box.</blockquote>

[QUOTE="Mark DeArman, post: 137947, member: 950"] Re: dB calculations Many manufacturers provide a sensitivity plot vs. Frequency for boxes or OEM speakers using a reputable piece of test equipment, not a Averaging SPL meter. And probably 75% of manufacturers at least measure the sensitivity with the proper tool and only report the one 'peak' number. This is exactly what we have been talking about in this thread. The whole idea behind a Averaging SPL meter, is measurement of uncorrelated noise signal. Like you said, the most common use of these devices is compliance testing for local and federal laws. These devices were not designed for measuring anything about a loudspeaker(s) and no professional really does use them that way, except to make sure their show is complying with the local laws. It is easy when looking at definitions online, to just read past a statement like, "uncorrelated noise," and assume that the math might still work out. It just doesn't work out; no more than playing pink-noise through a speaker, taking the FFT, and assuming that what you see is the frequency response of the box. [/QUOTE]

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