Thanks for the quick reply Wayne.
Phantom is on, and I can get a measurement by setting the input volume on the Tracker Pre to approx. 12 oclock.
Here is the procedure I followed:
Here's a "quick step-through" brucek wrote up some time back.
1. Prepare to run the Check Levels routine (Settings icon, Soundcard tab) selecting Check/Set Levels with Subwoofer in the Levels pull down box, with the SPL meter at the listening position and the dial of the meter at 80dB position.
Change Input Device Input and Output Device Output from Default to USB Audio, or the name of the soundcard, if that option is available, and Speaker for output, and Line In for input.
Begin the Check Levels routine. Ensure the REW output VU meter is at -12db and the Sweep Level at -12dB. If those fields are blank, check the two Control Mixer Volume boxes.
Set the Wave Volume at 1.000 and the Output Volume about ~0.500. (If those fields are blank,).
Adjust your receivers volume control so the actual standalone Radio Shack SPL meter reads ~75db at the listening position.
Then adjust REW Input Volume to end up with -18dB on the REW input VU meter.
2. Still in the Settings section, run the Calibrate SPL routine (in the Meter Tab) to match REW's SPL meter to the real SPL meter to ~75dBSPL. Make sure the “C Weighted SPL meter is checked.
3. Close Settings window. Run the Set Target Level routine (Target Settings icon to left of screen), which will set the target to ~75dB. Also, set the Cutoff, which is the crossover frequency you’re using
4. Run the Measure routine and set the End Frequency to 200Hz for subwoofers.
My problem is during the "Check Levels" procedure I think. I set the volume of my AVM-30 to get a reading of 75dB on my Radio Shack meter and then look for -18dB at the right input. Without adjusting the knob on the Tracker Pre, the input level is too low. If I try to do a measurement, a warning box appears.
Based on posts by Dennis H and others, I assumed I should be able to use the Tracker Pre with inputs set to Unity (full counter clockwise). This may not be the case, but for consistency I would like to be able to leave the input knob in a known state.