Domes vs. custom molds

I am a relatively new HA user (6 months) and I am doing pretty well with my Starkey RICs. The biggest problem for me is that the domes don’t fit that well. I have tried custom molds which feel great, but the sound is more occluded. My audi says that is the tradeoff I have to make: fit vs. occlusion. I guess I want to have my cake and eat it. It is possible to have custom molds that are no more occlusive than domes? Would I be better off with standard BTEs?

A friend of mine has custom molds with his RIC’s and his molds have about a 2 mm vent and he says he has no occlusion at all. Perhaps your audi ordered molds with to small of vent the first time around.

your audiologist should be able to bore out the vents a little at a time, or step them back a bit so you lose the occlusion.

agreed…more venting is likely the answer. I’ve got custom molds with no occlusion affects at all…

It is possible to have custom molds that are no more occlusive than domes? Would I be better off with standard BTEs?

You can use custom molds. You will need vents in the custom molds.
When opting for vents there are several solutions for the vents: direction (parallel of diverging, the diameter of the vent, the shape of the vent).

Depending on your type of hearing loss and requirements / wishes there is a solution. It may take more time to find the optimum solution.

Good luck !

I have had custom molds from the beginning (3 years ago) with a vent in them. I was told the main purpose of the vent was to allow the lower freq. in since I didn’t need much help at the low end.

I have had problems with feedback when using the click on domes. Custom domes are on order, so this discussion is of special interest to me. I get the custom domes later this week.

If the venting is too large, would that allow too much of the amplified sound to “leak” out? I am trying to stop the feedback (squealing). The audi had the feedback suppression at the maximum setting.

Is there a limit to the venting size to avoid both occlusion inducing feedback?

In general, if the hearing loss below 1000 Hz is 25 dB or less, an open mold (large vent (3.0 mm) or acoustic modifier) is recommended. If the hearing loss is 30-45 dB in the low frequencies, an acoustic modifier or medium vent (2.0mm) is recommended. If the hearing loss is 50-60 dB in the low frequencies, a small vent (1.0 mm) or pressure vent (.06-.88 mm) is recommended. When the loss exceeds 60 dB, we usually do not put in a pressure vent, unless the patient is occluded or their voice bothers them. When in doubt, put in a pressure vent, and plug it if it causes problems with feedback. The “Rule of Thumb” is that it is easier to plug a vent than it is to drill a vent. We use cushion grip, a denture adhesive, to plug vents. However, before plugging the vent with cushion grip, which is hard to get out of a vent, plug the vent with Fun Tak or clay to make sure the patient is not bothered by a plugged vent. If plugging the vent does not bother the patient (occlusion, resonance in his voice, etc.), then plug the vent with cushion grip. Note, we generally plug the lateral portion of the vent, since patients feel less occluded than when we plug the medial portion of the vent. However, if feedback is still an issue after plugging the lateral portion of the vent, try plugging the medial portion of the vent at the tip of the canal. Generally, feedback is less when the medial portion of the vent is plugged. If you need to remove cushion grip from the vent, just heat it with a hair dryer. Cushion grip can be obtained at most drug stores.

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NaidaUp -
Excellent post.
As you can see, my low freq. numbers just about fit your profile for an “open” vent. Fortunately, I had lurked on this forum for almost a year before getting HA. When I finally gave in, I thought I would go to Costco to save some dollars. The audi there wanted to sell me a closed system, which meant I could use my cell phone in normal fashion (I am on phone a lot during business day). He didn’t even suggest I might be able to use an open system.
I had learned on this forum what you stated above - that if my low freq numbers weren’t horrible - I could use an open fit HA. Went back to my HMO’s HA center and the first thing she suggested was an open fit Phonak. I have had custom molds from the start. In fact, I assumed for $4K for HA everyone would get custom fitted molds. It wasn’t until later reading, here, that many people spend mega $ and just use domes/molds that come w. the HA. To me that seems strange since no 2 ear openings can really be identical.
I have NEVER heard a squeal. Occasionally, I can hear a brief squeal as I remove the HA. Have had HA for 3+ years…

By the looks of it, you will be in the 30-45db section with needing a medium vent 2.0mm.

You have to look at everything from 1000htz and under.

Would you believe almost $8000 AUD for mine, and that was through the Australian Government’s own hearing aid section. Unfortunately Costco is about 1000km from where I live, but it is hoped that they set up here eventually. I’m not going to be slugged that much next time.

It has taken quite a bit of my persuasion for me to get custom molds. They have had me experimenting with closed domes, then double domes.

I wish I knew about this forum before I purchased my aids

While NaidaUP’s post was alright for general use, there is more to it than that. Realistically it has more to do with your overall preference for volume for speech. The louder you prefer speech to be, the more closed the vent should be to maintain the precieved loudness in your ear. Too open, and all sounds will sound tinny/shrill/unnatural due to all the low frequencies spilling out of your ear. In contrast, if your venting is not open enough, there will be too much bass/occlusion of your own voice in your ear.

Hi, that advice is right on point. Too open and it’s tinny, too closed and it’s occluded. The audiologists I have had concentrate on the brand, the chip, the style, the technology and so forth. The mold is just a low-tech afterthought. I believe that with the proper mold, I should be able improve the balance between sound quality and occlusion and achieve a comfortable fit. Question: how to find an audio or ha dispenser who has the skill and patience to do the best impressions, work with the factory and fine tune the molds. Would appreciate any experience and advice.

Admittedly, acoustic aspects of HA fitting have become a lost art to a degree. Acoustic solutions and modifications are more effective than electronic modification via the software nine times out of ten in my opinion.

Thanks, but how do you find a professional with the skill and patience to do it??? The manufacturers will just give you a list of their dispensers. Maybe on this forum we need a shared list of audiologists and dispensers in geographic areas that members have had good experiences with.

I’m not sure if the earmold for a RIC can have a adjust a vent as a standard earmold can, but it might be worth finding out.

They can indeed…the smaller version, but yes.

Yeah, no different from physicians or dentists or auto mechanics in that regard I’m afraid. Find some folks with HA, or friends of folks with HA nearby and get the best advice you can on reputation of your local dispensers.

That is a very good question… to which I have no answer for.

All I can say it do the opposite of what most people do. That means, if you find a great hearing aid practitioner, shout it from the rooftops and tell everyone about them :D. This is far more helpful than what most people do and that is to badmouth the incompetent ones.

In my area, I seem to have developed a reputation for solving problems, so at times I have the manufacturers referring ‘challenging’ patients my way. I think that is exeptional though.

Good luck.