SCA B16 compressor - THD+R adjustment

[PJD3]

Thanks for coming by. I'm hoping to run into someone that could help guide me toward a feasible way to do this final adjustment on the SCA B16. I'm a robotics tech by day and have access to nice Flukescopes and signal generators but am struggling to make ends on the best way to go about this with the equipment thats available. I've come to a basic understanding of what THD is and ways its calculated but still have a few holes in my brain on how to go about it. Unfortunatly, I don't have a scope available that directly mearsures THD+R. It looks like I may need to look at the harmonic distortion and noise separatlely and do some calculations or some other method I'm not aware of. Anything you could tell me, especially if you've done this yourself, will be most appreciated. There is one trimpot in the circuit that is present for this adjustment. I've built, tweaked and measured many things in electronics but, adjusting for the best THD+n is not one of them!

Thank you,

Phil