DCR difference.

jayam000 · 13th November 2010, 04:16 PM

I purchased subwoofer with thielsmall parameters.
The DCR claimed is 3.6 ohm mentioned by company.
But when i check with my digital multimeter it is showing 3.9 ohms.
This piece was specially tested for me by the supplier fotr thielsmall parameter.
When i ask them, they told that they put the same what is given to them by voice coil manufacturer.
I don't understand why there is difference with digital multimeters.

Speedskater · 15th November 2010, 11:07 PM

Much of the difference can be in the test probe lead wires and clips. Measuring low Ohms accurately is not easy. You could use a low Ohm 1 % resistor to check your meter and test leads. Some meters allow you to null out (tare or zero) the test leads.

bob91343 · 16th November 2010, 01:00 AM

A difference of 0.3 Ohms is negligible and probably due somewhat to measurement error.

jayam000 · 16th November 2010, 05:14 PM

Thanks for the help.
We first short the test lead & check the resistance.
Then check the speaker DC resistance. Then deduct the lead resistance.
This all is done still not understand why the error.

How much difference will be on thielsmall parameters like .qts, fs, spl & vas due to difference in DCR. ?

godfrey · 16th November 2010, 06:02 PM

Qts will be a little higher, spl will be a little lower (less than 1 dB difference). Fs and Vas stay the same.

More important - when you play music loud, the voice coil gets hot and it's resistance increases - this will make a bigger difference.

jayam000 · 17th November 2010, 03:33 AM

Quote:

Originally Posted by godfrey

Qts will be a little higher, spl will be a little lower (less than 1 dB difference). Fs and Vas stay the same.

More important - when you play music loud, the voice coil gets hot and it's resistance increases - this will make a bigger difference.

Thanks for info & nice explanation.

13th November 2010, 04:16 PM	#1
jayam000 diyAudio Member Join Date: Apr 2009	DCR difference. I purchased subwoofer with thielsmall parameters. The DCR claimed is 3.6 ohm mentioned by company. But when i check with my digital multimeter it is showing 3.9 ohms. This piece was specially tested for me by the supplier fotr thielsmall parameter. When i ask them, they told that they put the same what is given to them by voice coil manufacturer. I don't understand why there is difference with digital multimeters.

15th November 2010, 11:07 PM	#2
Speedskater diyAudio Member Join Date: Sep 2002 Location: Lakewood, Ohio	Much of the difference can be in the test probe lead wires and clips. Measuring low Ohms accurately is not easy. You could use a low Ohm 1 % resistor to check your meter and test leads. Some meters allow you to null out (tare or zero) the test leads. __________________ Kevin

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16th November 2010, 01:00 AM	#3
bob91343 diyAudio Member Join Date: Mar 2010	A difference of 0.3 Ohms is negligible and probably due somewhat to measurement error.

16th November 2010, 05:14 PM	#4
jayam000 diyAudio Member Join Date: Apr 2009	Thanks for the help. We first short the test lead & check the resistance. Then check the speaker DC resistance. Then deduct the lead resistance. This all is done still not understand why the error. How much difference will be on thielsmall parameters like .qts, fs, spl & vas due to difference in DCR. ?

16th November 2010, 06:02 PM	#5
godfrey diyAudio Member Join Date: Nov 2009 Location: Cape Town	Qts will be a little higher, spl will be a little lower (less than 1 dB difference). Fs and Vas stay the same. More important - when you play music loud, the voice coil gets hot and it's resistance increases - this will make a bigger difference.

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