I have known that my hearing has been getting worse over the last few years. I recently had a hearing test to confirm this and compared it to a similar test which was done 8 years ago. This confirmed my suspicions. According to the most recent results my speech frequencies are down about 30 DB more than previously noted. And I'm pretty certain that 8.0KHZ and above is even worse. The tinitus also tends exacerbate the problems further.
The test was rather interesting and informative and not unpleasant, until that is the examiner switched into "salesman" mode. I realize that these new aids have many new bells and whistles many that I will never use. In any case, to make a long story shorter, 4000.00 is not within my budget at this time. Unfortunately there is no money at this time for anything.
So I would like to ask, (and I've tried to pursue this before) but unsuccessfully is there any information on the DIY construction of a pocket unit with an earphone which has either a high pass filter circuit which rolls off the low frequencies, or a graphic equalizer that can be set for the frequency response desired?
I may be oversimplifying this a bit but it seems to me that if the amplifier had a response curve which was the inverse of my hearing curve, (similar to an RIAA or NAB equalized curve) then the amplifier would "pre compensate" for my deficiency.
I have found some circuits on the net but they don't seem to be frequency compensated. Amplifying the entire spectrum would be counter productive. Perhaps I could try coupling a full range amplifier using a very small capacitor on the input to roll off the lows.
One other option is this: I have my fathers old hearing aids. He passed away in 1993. I found his old test, and his response curves were very similar to mine. These are naturally much larger units than what's available today and although they're not a perfect fit, they do fit, and could I suppose be used. I am also told that new molds could be made and they could be "refitted" to my ear shape if I so desire as well.
I asked the "salesman" a hypothetical question. And that was if I did decide to try to use them what was the technology back in 1990? Were the aids frequency compensated or were they just a plain flat response amplifier? I don't know if the answer I received was bullshit or not but in any case it was not a positive one. Does anyone know the answer to this?
I'm semi retired now so I do have some time to fart around with something like this if I had the appropriate information. According to the test, I need to make up 55DB at 3.0 and 4.0 KHZ. I really wouldn't mind carrying a box in my shirt pocket with an earphone. Any help with such a project would be most sincerely appreciated. Lenny