Impedance measureent issue

[Eargasmik]

Hi everyone, i'm french so i'm sorry if my englosh writing is not perfect.

I built the cable to measure the impedance with rew. I double checked the connections with a multimeter and they are all fine. The resistance is dual 47ohms in series.

I bought an usb soundcard ( more a splitter than a soundcard...).

I plug the mono jack to the output, and do the open circuit cal, OK.

Then i want to do the short circuit cal, and i got an error message telling that it should be a difference between the reference and the measure, and there is no difference. Maybe the channels are swapped, or the aligator clips are not short.

I'm wondering if my input mic is only mono so it cannot see any difference between the loopback signal and the signal going through the resistor

I can take pictures if needed, and i searched a lot on this forum to find an answer but couldn't find. I changes all settings in preferences, input, output, and loopback channel ...

Please help

 

[John Mulcahy]

I plug the mono jack to the output

The output connector will be stereo, do not put a mono jack in it. Use a splitter with a stereo jack to access one channel of the output.

I'm wondering if my input mic is only mono

That is quite likely. If you look at the Windows audio properties for Recording devices on the Advanced tab you may be able to see if it is set for a mono format. You can find that in (for the English version of Windows) Settings - System - Sound then on the right hand side under Related settings there is Sound Control Panel, pick the Recording tab, select the entry for the soundcard, click the Properties button then select the Advanced tab and look at the Default format setting.

 

[Eargasmik]

The output connector will be stereo, do not put a mono jack in it. Use a splitter with a stereo jack to access one channel of the output.

That is quite likely. If you look at the Windows audio properties for Recording devices on the Advanced tab you may be able to see if it is set for a mono format. You can find that in (for the English version of Windows) Settings - System - Sound then on the right hand side under Related settings there is Sound Control Panel, pick the Recording tab, select the entry for the soundcard, click the Properties button then select the Advanced tab and look at the Default format setting.

Thanks i'll check the windows settings. But i saw in the description of the soundcrd that it's a mono mic input...

Didn't understand what you mean with a jack splitter sorry. Sould i buy a splitter from one stereo to two monos and switch the channel from what i need??

I was looking to buy another soundcard with a stereo mic input but they are usually pricy and i don't need it daily...

Thanks for your help, don't find french enthusiasts about this process

 

[Eargasmik]

This is the cable i built like ''audio judgement'' show in a yt video.
The output comes from a mono jack. For the input the 2 positive plots, the first one is loopbck and the second one is post resistor measure.
Right?

So if i well underdtand i need a stereo ''inpit'' in my soundcard in order that rew can measure the difference between the two signals.

 

[John Mulcahy]

Yes, you must have a stereo input. You will also need a stereo to 2 x mono to access one output channel. @Bernard would fit the description of "French enthusiast" well

 

[Bernard]

Yes, you must have a stereo input. You will also need a stereo to 2 x mono to access one output channel. @Bernard would fit the description of "French enthusiast" well

I'll see what I can do...