My first calibration session with REW

**glaufman** · **11-06-09, 10:50 AM**

Would this be easier in a loopback mode, eliminating the speakers/mic/room?

**brucek** · **11-06-09, 12:26 PM**

Quote:

Would this be easier in a loopback mode, eliminating the speakers/mic/room?

Only with line level devices. The reference was to an amplifier, which becomes a bit more of a problem.

brucek

**michael123** · **11-06-09, 01:36 PM**

Quote:

subtract the THD+N from your test equipment first

Could you describe me this step please?

**brucek** · **11-06-09, 03:20 PM**

Quote:

Could you describe me this step please?

It has to be manually carried out. If I wanted to check the distortion of a 1 KHz tone though a looped device with REW, the THD and THD+N would be a full loop figure including the soundcard. If I wanted to increase the accuracy, I would examine the THD and THD+N of the soundcard and subtract that from the full loop figure.

brucek

**glaufman** · **11-06-09, 04:32 PM**

Quote:

brucek wrote:

Only with line level devices. The reference was to an amplifier, which becomes a bit more of a problem.

brucek

Ah, well, you're right again!

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