Both the AR888 and the Fleabay version (I recommend the Chartres Resonator Mk2 version for better resolution and detail, esp with +12V LPS, there are tons of suppliers for that on Fleabay as well).
Positioning the AR-888 or alternative product is key, you need to experiment. I recommend the first one in the middle between the speakers, between 5ft and 6ft, the second one either on the back wall or on the side wall at the reflexion point (the same location you would put an acoustic panel).
This tweak has no downside: it does not change the soundstage or induce imbalance but, because of how it functions, "cleans" the air in your listening room, resulting in more details and increased clarity. Other tweaks or cables can have side effects. IME one of the best tweaks!
Positioning the AR-888 or alternative product is key, you need to experiment. I recommend the first one in the middle between the speakers, between 5ft and 6ft, the second one either on the back wall or on the side wall at the reflexion point (the same location you would put an acoustic panel).
This tweak has no downside: it does not change the soundstage or induce imbalance but, because of how it functions, "cleans" the air in your listening room, resulting in more details and increased clarity. Other tweaks or cables can have side effects. IME one of the best tweaks!