Ozzy,
I am using an oversize copper sleeve. They are sitting on a table behind the speakers. I use copper sleeves throughout my system on IECs and ICs. But even with the copper sleeves the XOTs are a no-show in my system. This is probably because I am using so many Bybee products from amp to speakers. I am sure the XOTs work for many people who don't have a similar set-up. I will be putting my XOTs on offer soon.