Trouble with impedance measurement

Ole Kristian Sekse

New Member
Thread Starter
Joined
Nov 9, 2018
Messages
6
Hello!

I`m trying to do an impedance measurement of my speakers but have an issue.
I have a Macbook Air with REW installed, and have USB souncard connected, Focusrite Scarlett Solo mk2.

Have connected all up as in REW manual:
https://www.roomeqwizard.com/help/help_en-GB/html/impedancemeasurement.html

The trouble is that I cant get signal on mic in on both the left and right at the same time, and then I get no result of the impedance measurent.
I can choose between L or R to signal input, and they both work.

Is this an REW, Mac or Focusrite trouble?
Hope to get som help :)

Best oks
 

John Mulcahy

REW Author
Joined
Apr 3, 2017
Messages
7,212
It would be very tricky to set up for impedance measurement with a Solo, two input channels are required for impedance measurement and they need to have the same gain, ideally unity. I'm not sure it is possible to set the mic input gain low enough to match the line input and you'd also need to drive the balanced mic input single-ended. Better off using a card that has a pair of line inputs.
 

Ole Kristian Sekse

New Member
Thread Starter
Joined
Nov 9, 2018
Messages
6
Thanks for answer! :)
tricky you say....ouch... :(

Can try reconnect and use both inputs, but don`t know if REW will take this...
And gain will be a problem yes...
 

Ole Kristian Sekse

New Member
Thread Starter
Joined
Nov 9, 2018
Messages
6
Got this working by using both inputs on Solo.
Both connected as single ended.
Adjustet gain on inputs by using 10ohm resistor.

But yes, better using card with line inputs.
 
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