Martin Poulin
MAY 2018
I purchased a Dayton Audio DATS impedance analyzer V2
This tool is very useful for confirming speaker parameters and finding break-up mode (they often show up on the impedance plot)
Often, manufacturers are optimistic on specifications (Tang Band comes to mind) and designing an enclosure using published data which never yield best results.
Below is a measurement value of a Scan Speak 18W8424G00 (Discovery series) I happened to have on hand.
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Qes from Scan Speak is supposedly 0.51
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The measured Qes comes in at 0.67!!! (30% more)
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Qts obviously changes because of the Qes.
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This speaker is well burned in, so this much difference is surprising, from a reputable manufacturer like Scan Speak.
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The VAS is also double the specified value!
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FS is reasonably close.
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MMS is also close enough.
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However, with such an QES variance, this means that before cutting a box, speaker measurements are mandatory!
