# my first impedance test



## eastman17c (Sep 15, 2011)

Hi ,

I would like to ask if this response is normal? for my first impedance test set up for my Crown speaker.
thanks


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## jtalden (Mar 12, 2009)

It looks normal :T


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## fusseli (May 1, 2007)

Looks typical for a single driver! Must be a large PA speaker?


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## EarlK (Jan 1, 2010)

> The curve looks good ( for a single 16 ohm transducer having an Fs of 32 hz ) .

> OTOH, If the pic is a measurement for a woofer within a ported box, then you have big problems .

> Does a known value resistor ( such as an 8 ohm resistor ) measure correctly ( allowing for the resistors stated tolerances ) ? 

:sn:


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## eastman17c (Sep 15, 2011)

it is a 15 inch driver tested alone no enclosure as per label 45 hz is the FS, the impedance is 8 ohms 200 watts nominal the resistor in series was 27 ohms 10 % tolerance . the speaker placed in the floor with wood support facing the wall , I like the REW 5 thanks to Mr. John


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## fusseli (May 1, 2007)

Look how far off that Fs is from spec, then. This happens a lot. Vas can vary a whole bunch also, which along with Fs change how a speaker performs in a cabinet very much. This is why measurement-based design is the way to go


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## eastman17c (Sep 15, 2011)

Here is my next image of free and added masses test , I was confuse since the result of TS parameters is lacking of 3rd and 4th column Vas and other parameters were missing. I cannot find why is that happen, please help thanks


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## JohnM (Apr 11, 2006)

Can you post a screenshot of the TS parameters window, please?


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## eastman17c (Sep 15, 2011)

Here under is my TS parameters that I cannot find the reason why some data is missing . Is my computer is slow speed that is why cannot produced the result? thanks


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## JohnM (Apr 11, 2006)

Are you using the latest V5 beta version? If not, download it from this link.

Once you have the latest version installed, load your measurements, on the TS window select the free air measurement and then select the added mass measurement as the "secondary measurement", then click the "Calculate Parameters" button.


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## eastman17c (Sep 15, 2011)

I will download the program then try again. thanks sir


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## eastman17c (Sep 15, 2011)

Hi John

I downloaded the new beta but and installed it already but still have problem with missing parameters , I change the sweep to narrow from 20 to 4000 Hz but still wont work. do I have an error in my measurement ? thanks


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## JohnM (Apr 11, 2006)

Please post an mdat file that contains your two measurements, the free air measurement and the measurement with added mass.


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## eastman17c (Sep 15, 2011)

Here is the two Mdat files


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## JohnM (Apr 11, 2006)

I was meaning to attach the actual measurement .mdat files rather than graph images, but the second image shows a possible source of the problem. You seem to have added so much mass to the driver it has almost no resonant peak remaining so the curve fitting has failed. Try making a measurement with much less added mass.


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## eastman17c (Sep 15, 2011)

Ok , uploaded the mdat files already sir and I will test again with less mass added, hope I can fix this time. thanks


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## eastman17c (Sep 15, 2011)

I tried to check my measurement result with Limp against REW the graph image is is equally the same but TS parameter result is not the same , Im still finding the missing parameters and not yet found the problem. thanks for the help


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