That's good to know. You can also try doubling the thickness of egg style foam to see if it improves some more.
I think a higher density absorbing material will ultimately be your solution for the Odysseys if you are looking for further improvements. Several materials have been presented here.
On a separate note, what is the dB value of soft and loud volumes you are listening to? If you don't have an SPL, several apps can be downloaded for free. For me loud is 80dB or more, and the panels remain effective at minimizing the reflections. As you pointed out, the louder it gets the more effective the results.
I think a higher density absorbing material will ultimately be your solution for the Odysseys if you are looking for further improvements. Several materials have been presented here.
On a separate note, what is the dB value of soft and loud volumes you are listening to? If you don't have an SPL, several apps can be downloaded for free. For me loud is 80dB or more, and the panels remain effective at minimizing the reflections. As you pointed out, the louder it gets the more effective the results.