1/10 octave or better can be achieved by both TrueRTA and by REW.
The reason that RTA is not useful is that it has little memory while the major room influence is in the delayed reflections and their interactions. For that, you need to see "waterfall" plots or similar that show how the sounds at different frequencies decay in the room. Generally, one wants uniform decay of all frequencies.
For more info, I recommend Toole's new book "Sound Reproduction - Loudspeakers and Rooms." I am about half way through it now.
Kal
The reason that RTA is not useful is that it has little memory while the major room influence is in the delayed reflections and their interactions. For that, you need to see "waterfall" plots or similar that show how the sounds at different frequencies decay in the room. Generally, one wants uniform decay of all frequencies.
For more info, I recommend Toole's new book "Sound Reproduction - Loudspeakers and Rooms." I am about half way through it now.
Kal