Mold Vents

I recently got a new set of BTE aids and molds. There is no vent hole in the molds. My old set had a small vent hole. Is this new technology to have no vent?

I am not in the industry, only a user. There are likely are not any “new” technologies that eliminate the benefits of having vents to minimize occlusion. But I can only assure you that my latest and greatest ITE Ambra hearing aids have vents and they can exist even larger because of the feed back defeating ability of the newer firmware.

I think you are right to ask questions about having none.

TerryB

I have sent my audiologist an email asking the same question and am waiting to hear from her also. I was just wondering if they stopped putting vents in for some reason. Thanks for the reply…

They have not. I would not be without pressure vents in my molds. I once got a set without vents - it was a mistake and was changed straight away.

The size of the vent is critical. Depending on how much gain your hearing aids put out, too large a vent and the processors can be consumed with eliminating the feedback. Too small a vent and you still experience the occlusion effect.

I have appointment 1-7-11 to have the vents put in the molds. My audi said she was concerened about feedback with vents. Is she feeding me a line of _ _?

Feedback is caused by the sound coming out of the hearing aid inside your ear returning past the aid (or through the vent) and getting into the microphone again. The gain of the amplifier raises the output and the vicious cycle continues to ramp up causing the squeal which is the natural frequency of the system going round and round. Vents are a factor in feedback as is the gain if the amplifier, the distance between the components, etc. But, as I mentioned, modern aids have an adjustment to stop it from squealing and she should have adjusted the other components to minimize the chances while maximizing your comfort and the aid’s utility for you. It’s all the big magic mixture called fitting.

TerryB

I have new full shell molds and no vents what so ever, antiallergic type of silicon maybe, not sure exactly what they are made of, they are flesh colour… I was told they were a new type material for molds? Must say they are very comfortable and although they seem hard at first, they become very flexible, most probs from body heat? Now I have always had major problems with any molds, occlusion, ear infections, sores, scabbing etc’ never had a mold before that I never filed down!

These baby’s fitted first time, so far with none of the above and no vents, I’m totally delighted with them:D

Cheers, Kev:D

5 years or so ago, earmolds and ITE aids would typically need some adjustment. For a large loss such as yours, it was important that the fit be on the tight side to suppress feedback. Modern earmold and hearing aid shell manufacturing has undergone a revolution in the last few years. Computer modeling is able to produce supercritical fittings not attainable when shels were made by hand. Modern anti-feedback schemes will also make a tight fit on a hearing aid less important. This means that it’s possible to insert a new hearing aid or earmold into the patient’s ear and not have to make adjustment to the fit. This was unlikely to happen just a few years ago but nowadays it’s routine.

Vent sizes will vary wildly on hearing aids. Earmolds without any vents implies that you have a large loss which requires a lot of amplification. The new anti-feedback schemes have created a revolution in hearing aid fittings and make possible the new open fit hearing aids and have totally changed the way hearing aids are fit and sold.

OTOH, if you have a large loss in the low and high frequency regions, you might still require an aid with no vents.

Yes, sometimes, you must accept some occlusion!

JLHOG, with no vents in the mold, are you feeling you have an issue with occlusion? Occlusion sounds like you have earplugs in, or a really bad head cold. Voices (especially everyone else’s) sound “wrong,” muffled. Chewing a hard food like almonds drowns everything else out. With ear molds, chewing hard foods may be louder than without ear molds and your voice may still sound different to you, to an extent. It goes with the earmold territory. But if everything else sounds okay, that’s not a serious occlusion issue, and I would not ask to have new or bigger vents put in the molds, because if you do, you will increase your chances of feedback. Since some people do have molds with no vents, your audiologist may have made the right call for you.

I’ve had two sets of custom molds since getting my new aids a couple of months ago. The first mold with a very small vent did sound too occluded, to me. The next pair had a slightly larger vent, and now it sounds great, and I’m not getting feedback.

There’s a balance point for molds. Vent too big -> feedback, vent too small -> occlusion (and the difference in vent size between occlusion and feedback for one user may be small.) Of course there are other variables, but from the user point-of-view, it tends to go that way.

Yes and vent size has a marked effect on bass/lower mid frequency response. Ed

As a repair technician that made ITE aids using prewires, I never did like vents - mostly they created a bit of uncertainty in the aid by wiping out most of the low frequencies and reduced the space available for the components and tended to create resonant spikes in the frequency response of the aids because of less space in the hearing aid shell. Of course, the fitters favored vents because of the more comfortable fit. The fitters were probably right in requesting vents but these days the components are a lot smaller and getting everything to fit is less of a hassle.

Thanks everyone for all the information. My ears do feel plugged up at times and that may be due to no vents also. Hopefully we can get the proper size vent the first time and all will be good.