distorsion

Hello,
I have a not bad sound interface (Focusrite Scarlett 2i2), better than sound card normally.
Can I make distorsion measurement with it? Can you guys recommend a PC software for that?
I do not expect 0.000x % THD to be measured, but at least in the x% range?

I want to change components (bias of tube, to improve linearity) and see results immediately. When I see minimum THD, than listen to it.

Thanks,
JG
 
Thank You both!

RMAA, I remember now, I have used it long time ago.
But, now, I would try the DiAna. I read the replies about virus protection and I have this problem with Kaspersky also.

Anyway, would the demo version work for measurement? If not, I do not fight with Kaspersky and just use RMAA.

Thanks,
JG