Martin Poulin
MAY 2018
I purchased a Dayton Audio DATS impedance analyzer V2
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This tool is very useful for confirming speaker parameters and finding break-up mode (they often show up on the impedance plot)
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Often, manufacturers are optimistic on specifications (Tang Band comes to mind) and designing an enclosure using published data which never yield best results.
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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!
