# REW V5 impedance measurement showing large offset



## PA5cAL1 (Oct 9, 2013)

Im completely new to measuring speakers. I wanted to measure the impedance of a speaker such that I could determine the TS parameters but the obtained results so far are not correct. To measure the impedance I have build the very simple jig with just a single 100ohm resistor. To make sure that the measurements are accurate, I first measured a 5.6ohm high power resistor. The measurement resulted in 107 ohm instead of 5.6, so something must be wrong. An offset of 101.566 ohm to be precisely was present. Next I measured a speaker (SB Acoustics SB17NRXC35-4) which also resulted in an impedance which was way too high, again the same offset was observed. I think I did everything correctly, I first calibrated the soundcard itself by connecting the output of the soundcard directly to the input. After calibrating the soundcard I calibrated the jig by shorting the 100ohm measurement resistor. Then I did the actual measurment of the driver. I can of course shift the data simply by 101.566 ohm because that data seems to look alright, it just has a very large offset and I have no idea why it is present. If anyone has an idea why this happens, let me know. Help would be appreciated.


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## jtalden (Mar 12, 2009)

I think I read that that this happens when the channels are reversed.


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