I apologize for my lack of technical skills right up front. After hours of bewilderment, I realized that the REW software is far beyond my abilities to learn and use so I downloaded HouseCurve, which functions similar to REW, and got a tone sweep of the sound in my room, which showed a big "hump" at about 50Hz and a null at around 350 Hz. The graphs are revealing, but what to do with the information??
I just bought Fabfilter Pro-4 and learned that it is "plug in" to used with other music processing software like Audirvana, which I have. I have enjoyed applying EQ to the music I hear on AV, but so far as I can tell, the music curve that it shows is not related to any sound in the room so I am just doing the EQ adjustments by ear which is fun and useful, but does not necessarily yield a flat response.
Backing up, I formerly had a DSPeaker Anti-Mode which used a microphone to get a tone sweep of the sound in the room and then with a press of a button, it would EQ to the sound as flat as possible. That is what I am hoping to get back to, something simple. I'd buy a DSP Anti-Mode again, but without a tape loop in my preamp, I don't know that I can connect it.
If there is a way to incorporate a tone sweep of my room into AV for initial EQ levelization, I sure be happy to learn about that. Any help would be really appreciated.