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Old 10th January 2011, 09:59 AM   #1
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Default Possible use of a very low QTS driver?

Hi all,

I have a TB W4-656 midbass driver. According to the datasheet it should have a Qts of 0,33. I measured instead a value of 0,16.

Apart from the annoying discrepancy, what is the best enclosure for such a low Qts?

TIA, Ralf
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Old 10th January 2011, 11:11 AM   #2
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That seems very low, maybe you need to check your method was correct. If it is that low, you would have to use a ported box.
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Old 10th January 2011, 01:29 PM   #3
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Such a driver would be suitable for a horn, but I do also suspect a measurement error.

Regards

Charles
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Old 10th January 2011, 01:39 PM   #4
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First time a Tang Band, (or most any driver) measured lower than spec'd?
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Old 10th January 2011, 02:43 PM   #5
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I used the added mass method on Limp with this jig: ARTA Jig
Only need to run a sweep, measure driver diameter and DC resistance (on a ohmmeter across terminals). What could I have done wrong?

I suspect that the driver is NOS, and probably sat unused in a warehouse for some years. Could this be the problem?

Ralf
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Old 10th January 2011, 02:58 PM   #6
a.wayne is offline a.wayne  United States
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Manufacturers Qts specs are usually lower than actually measurements, never seen it the other way hevar .


Vented box for sure ...
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Old 10th January 2011, 04:05 PM   #7
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Quote:
Originally Posted by giralfino View Post
I used the added mass method on Limp with this jig: ARTA Jig
Only need to run a sweep, measure driver diameter and DC resistance (on a ohmmeter across terminals). What could I have done wrong?

I suspect that the driver is NOS, and probably sat unused in a warehouse for some years. Could this be the problem?

Ralf
The mass needs to be accurately known and change Fs by approx 50 percent. You need to include a third of the surround in the cone diameter measurement. Did you take a baseline DC resistance reading to account for lead resistance?

So potential for a lot of errors really!
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Old 10th January 2011, 04:12 PM   #8
godfrey is offline godfrey  South Africa
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How do the rest of your calculated values compare to the specs? e.g. Moving mass, compliance and resonant frequency.
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