subwoofer/speaker terminology book

joshpoints
10+ year member

CarAudio.com Veteran
Does anyone know any good books that go into detail on what terms like BL, Vas, Qms, Qts, Mms, Cms, Qes, Fs, Re, Sd mean? I want to know the defintion and how to apply it to a speaker. I don't want strictly defintions like the one below that doesn't apply it or give an example of what this means for performance; what's a good number what's bad.

Qms = Mechanical Q of the driver at Fs. Qms is a measure of the driver's tendency to resonate at Fs, based on its mechanical characteristics, e.g. surround compliance, the compliance of the spider, weight of the cone, etc.

 
Something I'm noticing with each company is they seem to leave out enough of these parameters so you can't quite do a direct comparison. Is this done purposely? Some will list the Sd but won't list the Xmax. Some list Xmax but don't list the Sd so you can't figure out the Vd.

 
Most of them have "tech sheets" somewhere on their website that you need to hunt and dig for to get all the info.

And then, ofcourse, you have the problem of non-comparable data. For example; one company will list Sd using the 1/2 surround method (RE), while another company will list Sd using the 1/3 surround method (most everyone else). Or one company will list Xmax as a peak-2-peak figure, only not denote it as such. Or they'll list Xmax as a mechanical limit rather than a linear limit. Etc etc.

So, just a warning to not take everything at face value.

 
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joshpoints

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