Managed to get this combination of hardware working in REW, and wanted to explain my steps
** Calibrating the Art Usb as a "Soundcard":
The "ART USB dual pre" (herein ART) was set as an input AND output device following the "REW and OS X" instructions on hometheater shack
On the ART, I turned the mixer to "Computer", and verified the sound coming from OS-X was outputting on the left "monitor output" on the ART the "headphone output". Did this by playing a song via itunes through a headphone connected to the headphone outputs and turning the volume slowly up on the ART.
Followed the instructions in the REW manual to get the soundcard measurements. Specifically, I took a 1/4 inch phono cord and looped it. It went from the left "monitor output" on the Art box to the left mic input. I accidentally left the phantom power on and it didn't blow up. Without phantom power, the measurement is about the same.
** Inputting the MIC calibration file
Then, in REW preferences, I went into the "Mic" panel and inputted the file downloaded at the Datyon site. No problems.
** Measuring speakers
I managed to do some initial testing and equalization that made the speaker sound much better :T .
Once I figure out how to do this part correctly, I'll post the results. What I did temporarily is cut a few corners. :nono: I turned the ART mixer back to the "Preamp" side away from the "Computer" and used the Os-X mac's built in soundcard for output, by going back to "Audio MIDI setup" and setting the default output to the internal output on the mac. Then I used the internal output to drive the speaker. This defeats some of the utility of calibrating the ART, although helps because it still calibrates the preamp input function.
** Calibrating the Art Usb as a "Soundcard":
The "ART USB dual pre" (herein ART) was set as an input AND output device following the "REW and OS X" instructions on hometheater shack
On the ART, I turned the mixer to "Computer", and verified the sound coming from OS-X was outputting on the left "monitor output" on the ART the "headphone output". Did this by playing a song via itunes through a headphone connected to the headphone outputs and turning the volume slowly up on the ART.
Followed the instructions in the REW manual to get the soundcard measurements. Specifically, I took a 1/4 inch phono cord and looped it. It went from the left "monitor output" on the Art box to the left mic input. I accidentally left the phantom power on and it didn't blow up. Without phantom power, the measurement is about the same.
** Inputting the MIC calibration file
Then, in REW preferences, I went into the "Mic" panel and inputted the file downloaded at the Datyon site. No problems.
** Measuring speakers
I managed to do some initial testing and equalization that made the speaker sound much better :T .
Once I figure out how to do this part correctly, I'll post the results. What I did temporarily is cut a few corners. :nono: I turned the ART mixer back to the "Preamp" side away from the "Computer" and used the Os-X mac's built in soundcard for output, by going back to "Audio MIDI setup" and setting the default output to the internal output on the mac. Then I used the internal output to drive the speaker. This defeats some of the utility of calibrating the ART, although helps because it still calibrates the preamp input function.