Would it be this one?
That all sounds pretty good. The 2.5mm SAV could be the smallest they go. The people at Lloyd’s gave me the impression 3.0mm was the smallest but not sure about that. I do believe following the recommendations from the software is the right way to go. Fine tune from there. Having feedback issues would give me more reason to follow recommendations.
You are good!
That’s it.
Great information.
My audiogram is worse than Sierra’s just looking at the aviators.
Next week I will receive new ear molds to put on Naida UP aids. If I can get high frequencies to come back to my hearing Sierra should be able to also.
I believe his 3000-4000 hertz issues will go away with the right molds. Like me, I suspect he will think he has new aids with molds.
You may very well be right, but I’m skeptical as heck. Your audiogram is a lot different though as you’d require a lot more gain in lower frequencies which I would think make them less likely to get masked over. Do you know if you’re using any frequency lowering? I’d think you’d be an ideal candidate and the Naida Vs have a great system. I claim no expertise but I am pretty well read on this stuff.
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Yes to frequency lowering. I have been tinkering with some non-fitting molds on #13 tubes for a week or two, promising. Looking forward to getting the correct ear molds. I am hopeful it works well for me.
I have read the move away from domes to ear molds is needed in the low frequency 35-45 dB range, maybe a little less. Sierra is right there.
I am the furthest thing from being an expert. Just trying to learn.
Pressed in…no feedback with hand over ear:
Hopped on my recumbent trike, lowered volume 6 dB, rode to library, upped volume 6 dB, read Wall Street Journal, shopped at Safeway, dropped volume 6 dB, rode home, upped volume and took second picture:
They really don’t move much. Still no feedback unless I really press my hand firmly over my ear.
They are very comfortable.
Thanks for your reply! Can you give us a link? The listing you provided for them seems to be an image and not clickable.
Best wishes, Nate 
These are sold by quite a few sellers on eBay.
Thank you! Always worth trying something new when the cost is so reasonable!
VENTING?
So I think my thoughts are now fairly settled on mold type and material. It will be up to the fitter of course, but I’m currently thinking a canal lock style, and either two types of silicone, or standard silicone to help with the feedback issue.
Venting however is not as obvious. My hearing at 500 Hz is only down 25 dB, so closing down on the vent size to get low frequency gain is not an issue. My real issue is feedback. From what I can see in my research is that when it comes to high frequency (3-4 kHz) feedback isolation then the smaller the vent the better, and no vent the best. I found this slide in a presentation on Earmold Acoustics which is is quite good.
It would seem that a 1 mm vent would give about 20 dB maximum insertion gain over a open dome, and not much less than a total occluded fit. There also seems to be other advantages of small vent. From that slide presentation it is claimed that if the vent transmitted sound and receiver generated sound are within 10 dB of each other, then the two sources will interact due to phase differences. A smaller vent maintains the dominance of the receiver and lets the HA control the sound. Also background noise cannot be controlled if the amount coming in through the vent dominates the receiver. Another advantage seems to be maximizing the directional ability of the microphones if natural vent sound is minimized.
In fact there seems to be a lot of advantages to a small vent and only one disadvantage - occlusion. However the KS8 HA’s have Own Voice Processing which helps to minimize the own voice issue. I find it quite effective with the current closed click sleeves, and not a problem.
So now I am thinking that perhaps I should be getting 1 mm vents in both earmolds, and in effect going for occlusion and the associated advantages of reducing feedback mainly, but also better noise reduction, minimizing sound source interaction, and hopefully overall better speech recognition in noise.
Comments? Issues with that approach? This would be going smaller than the Connexx software recommends, which is 1.3 mm on the left, and 2.5 mm on the right. However, going smaller seems to be the conservative side of the tradeoff…
Sounds like a game plan.
Curious to hear what your audiologist says.
Your thoughts are very similar to what I will be getting this week.
The advantage of Select-A-Vent is that you don’t have to commit to a vent size but can play around and find the size that you like best. There is the following info that I posted out of Harvey Dillon’s 2012 Hearing Aid book - which you’ve seen before. Dillon says there are effectively only 2 or 3 actual venting sizes attainable with Select-A-Vent because, for example, it’s hard to achieve total occlusion due to leakage around the mold so, for example, he says that no vent will basically be about the same as a 0.5 to 1 mm vent, etc., (might be described in more detail in some other previous post of mine).
Yes, there is theory and then actual performance. One of the ways I have rationalized that I am having feedback when the size of the vent in my current closed click sleeves (1.6 mm) would predict I should be free of feedback, is that there is leakage around the click sleeves. When I went from open click sleeves to closed click sleeves the Connexx software reduces the streaming equalization for bass I presume on the basis that less bass would be lost through the much smaller vent. However in actual practice I am getting really poor bass with the closed click sleeves. I am no attributing that to leakage around the sleeves. My hope is that the custom mold will significantly reduce that leakage.
But, I guess where I am at now is that perhaps there is no “optimum” sized vent providing I am willing to deal with the occlusion. i.e. smaller is better… And perhaps when one is realistic about leakage and are willing to count on it, then perhaps no vent is an option.
I also see in your previous post with diagrams from the Dillon book, they seem to be the same ones as are used in the slide presentation I gave a link to in my recent post. They are quite helpful in understanding what is going on with vents.
My comments would be to look at the critical gain analysis to make gain adjustments and to be cautious of the custom ear molds as from my experience they do not necessarily fit as well as properly fitted domes or sleeves. Especially if you have small or twisted ear canals.
My mother has KS8 hearing aids with moderate to severe hearing loss. Her right ear is worse than the left. She has small ear canals that are also at an odd angle. She started with closed domes, but those would not stay in place. Went to closed click sleeves and still experienced problems with feedback and getting them in correctly. Next she tried custom ear molds which she and I were very disappointed with. They were large blocky and really only sat in the outer ear. They did not really fit in the ear canal. They were not what I thought would be custom. They were the worst of the worse as they kept falling out. She went back to the click sleeves while they sent them out to make new ones. She still experienced feedback, but learned to better insert them. When we went back to try the new custom which were really no different than the first ones. The tech ran a critical gain analysis and based upon that reduced the gain in the pinch point areas. With the gain adjustment and practice at putting them in and finally understanding that she has to check the click sleeve alignment she is very happy with them. We returned the custom ear pieces for full refund. She still has to watch the insertion and sometimes make an adjustment to get them to work.
Thank you for the comments. I will keep that in mind. My conclusions so far on custom molds is that a soft silicone seems to give the best acoustic isolation, and the more you have of the mold in the ear canal the better the isolation, and if you only have a short amount in the ear canal you really can’t make up for it with addition in the outer ear – other than to try and hold it in place.
The part about your mother’s experience that doesn’t seem to make sense is that a twisted ear canal is considered beneficial as it lets a canal type lock in place without a lot of assistance from the outer part. That said, I’m thinking that the smaller and more crooked the ear canal the harder it is likely to get it in place, especially if the mold material is soft.
I guess in the end I will have to rely heavily on the fitter’s experience in evaluating what can be done with my specific ear canals.
I’d say it’s one of these YMMV issues that depends on the shape and size of your ear canals, how good an impression your provider makes, and who makes your molds . Domes are made in a fixed set of sizes to a regular geometrical shape and the attachment point at the base on a tulip dome can be an odd, poor fitting solid object in your ear canal in spite of the ability of the tulip “petals” to accommodate various canal sizes. I had my molds made by ReSound and they follow a 16:4 rule, the mold from the entrance to your ear to the inside should be at least 16 mm long and go 4 mm past the first bend of your ear canal. If one has any waviness or undulations in the shape of your ear canal(I do), the mold captures that and the uneven mold shape forms a grip to hold the molds firmly in place (my molds do not slip in the least - but whatever dome I wore did not either, as I used concha (“sports”) locks when I wore domes). The undulations that I’m talking about can be seen in the shape of my right mold in the linked picture below, as well as a notch in the mold near the point of receiver insertion (red arrow) that appears to catch the crux helicis above my ear canal and also help hold the mold in place. In any event, one (bird) swallow of any sort does not a summer make, but looking over many posts on the forum, especially with severe hearing loss, most people who are willing to go to the extra expense of having good molds made get pretty satisfactory results and as far as trapping low frequency sounds within the ear to prevent loss of amplification when you most need it because of severe loss, molds offer a thickness of material compared to domes (don’t know about click sleeves) that better traps low frequency sounds within the ear canal. Works the other way, too. Because I’ve chosen an occlusive mold, when I want to block out extraneous sound, I turn my HA’s down or off, and much less outside noise comes into my ears with my molds in place than I’d hear if I were wearing tulip domes or power domes (again, have never tried click sleeves).
Should emphasize that good custom-made molds fit your ear canals perfectly, as mine do.
Thanks Jim for another good and detailed response. I’m learning!
As an update I went in for my mold impressions today at Costco. Took about 30 minutes to do both ears. Not unpleasant at all. Some learnings:
Costco in Alberta does not use the OTO Hearing company that I suspect they did. They only use them for custom ear plugs, and sometimes for receiver behind the ear tube type HA’s. For RIC HA’s they use the manufacturer – essentially Sivantos for Kirkland, and Rexton. Interestingly they ship the impressions out east to Ontario for scanning, with the digital details going to Holland in Europe for manufacture. So it takes up to 2 weeks to get them. I guess the reason is that RIC molds have to be made specific to each manufacturer’s receiver. I should have known that, but did not really think about it…
In any case I will be getting straight canal type silicone molds with no external retention features. The fitter did not think it was necessary. Assuming there is room for them, they will both have Select-a-Vents, so they can adjust the venting on site here. She says they will make the molds as many times as it takes to get them right and they can be returned if I am not satisfied with them. Seems hard to beat that for service. The Canadian cost is $80 each with some paid by our government health care to bring the cost down to about $135 for the pair – about $100 US.
I sure hope this is the solution to getting a good fit!
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