Power dome vs open dome

Power dome helps keep sound in ear canal. It allows for more gain without feedback. It is particularly helpful for low frequency gain but is useful for all frequencies. It also helps reduce outside noise from getting to your ear.
Voices being sharp is because you’re getting more high frequency gain. Hard to tell if it’s related to the domes or the hearing aid settings (likely both–the domes likely allow more high frequency gain)
Posting your audiogram (Top of page, click on FORUM and then My Hearing Tests) would allow us to see how appropriate dome choice is for your loss. The typical issue people complain of when moving to closed domes is “occlusion” (own voice sounds very loud, chewing sounds very loud) but most people adjust to it over time.

Echo is one symptom of occlusion. I find it strange that you are going from an open dome to a power dome. Has you hearing got that much worse?

I would have expected to see you go from an open dome to a vented dome or vented mold.

@user990 said:

I would have expected to see you go from an open dome to a vented dome or vented mold.

Hearing is worse after a few years, but not big difference. My audiologist ordered power dome at the first fitting . I will ask her about it at our next appointment. I feel that the dome plays some role in my difficulty of hearing through the new aid.