Resound Linx - vocal fry sound

Does anyone have Resound Linx hearing aids? I'm wondering if anyone has experienced this: From the beginning, I have had a mild but annoying vibrating sound. I first thought a radiator somewhere was making the noise. Also similar to "vocal fry," if you know what that is. Something is vibrating, or reverberating. It's more annoying with phone calls and listening to audiobooks. So it's worse with bluetooth, but still present when just listening to a myself talk, for instance, without being connected to bluetooth. The bluetooth makes it more obvious because it's going right into my ear with no space. The audiologist keeps trying to adjust for it, but it's not helping. I will ask her to contact Resound. I'm not holding out much hope. I can live with it, but seems like I shouldn't have to, considering the cost of these. Any thoughts? Thanks.