A:Answer I'm not sure why someone who doesn't know the definition of the term you used answered your question but occlusion can be an issue due to many factors (size of ear canal, bone density, size of tip you're using). I have this issue and have found that the closed sleeve that comes with thee CRE-C20 provided horrible sound (particularly Own Voice) but the vented (or open) ear tips solved this. They are sold separately. The Connexx 3.0 ear tips that other hearing aids use ARE compatible with the Sonys so this is an option if the included closed sleeves are giving you issues.
