PC Headphones as Hearing Aid

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Hi Guys,

I have some hearing loss in one of my ears and wear a hearing aid to improve my hearing. I have not done a lot of research into the technicalities of exactly what a hearing aid does but as far as I know it increases the volume of the specific frequencies that you can’t hear that well, thus it is a non-linear amplification. Please correct me if I am wrong.

The problem comes in with listening to music and playing games on my PC. I use Sennheiser HD 558 headphones but must remove my hearing aid when I use them due to peak clipping.

What I am wondering is, why can’t we adjust the output to the headphones in the same way that a hearing aid adjusts the sound? So basically you insert your audiogram details into software on your PC which then amplify and modulate the necessary frequencies?

This have been bugging me for a while and I would appreciate your comments.
Thanks

 

[CataclysmZA]

Years and years ago I had some discussions with engineers from Phonak when I was about 13. My own Phonak hearing aid was tremendously ****ty - I couldn't listen to music with it, I couldn't talk on the phone with it and in general it was just sad and terrible. Some of the newer models that have adjustment levels are great so long as you take them in for tuning every now and then, but they miss out the bass and put the treble up too high.

I know that about a year after I spoke with them, Phonak actually took one of my suggestions and implemented Bluetooth into their newest (far out of medical aid's reach) model. It still suffered the common issues of Bluetooth headsets because they compress the sound quite a bit, but I've seen demos of them working properly with cellphones.

Bluetooth 4.1, so far as I know, solves these issues but it still hasn't been implemented. I haven't been in to get a new aid in years. My current one just needs tuning and I'm deaf but I can hear most things, so going without it doesn't make things harder. I also understand that the way it modulates sound means that you can't normally just plug in any digital audio source, because that would require a much bigger unit and completely different software.

I'm actually less irritated with the fact that I'm deaf than the fact that I'm left-handed.

 

[Beachless]

Is that not what an equalizer does?

I'm sure if you dig around you can find one where you can adjust it per channel and maybe even set custom ranges.

 

[CataclysmZA]

I wish it were that simple, but you'd still have the hardware issue where the hearing aid can't keep up with the sounds you're pumping into it. Newer ones have better and faster ARM chips and can keep up with the audio streaming into them, but they still cannot convey bass properly. Some, like my older unit, also miss certain sounds completely because the device's firmware doesn't know to amplify it or just ignores it completely.

There's still no easy way to hook up a hearing aid using wires to a device you own, like an MP3 player or handsfree kit, and when you use it normally you're stuck with terrible positioning of the microphones, so that loudspeaker misses you completely and stereo headsets with small drivers don't give you their real power.

Also, the software to tune these things is expensive and the connectors for them are only available through whatever company makes and sells them (e.g. Phonak). I'd have to be a practising ENT specialist or hearing specialist to qualify to order a kit for myself.

Edit: Looks like Phonak actually does have a wireless connection going on for its latest hearing aids. The ComPilot looks like the Bluetooth accessory I'd suggested to them years ago, that's pretty sweet. The TVLink S looks like a base station for the ComPilot, probably uses RCA cables or something. The ComPilot probably has a mike in it as well.

Damn, I wish I had a medical aid for these kinds of things.

 

[InvisibleJim]

I found this link for an open source project to incorporate hearing aid functionality into an iPhone.

They have links to a fairly detailed description of the algorithm they have developed. Basically it works in a similar way to a graphic eq and uses a number of digital bandpass filters to modify the frequenxy response. This type of system could be implemented purely in software but could also be built into a dedicated embedded device built around an eg. an ARM chip or maybe a dedicated DSP chip which aren't especially expensive.

Just doing a quick search, there also seems to be a couple of other things that complicate matters such as audio compression.

Newer ones have better and faster ARM chips and can keep up with the audio streaming into them, but they still cannot convey bass properly.

I'm wondering if the bass roll off is because hearing aids are not so much designed for specifically music (and possibly in part because of the frequency characteristics of the speaker.) With most audio systems you get a roll off at high and low frequencies.

 

[CataclysmZA]

I'm wondering if the bass roll off is because hearing aids are not so much designed for specifically music (and possibly in part because of the frequency characteristics of the speaker.) With most audio systems you get a roll off at high and low frequencies.

That's part of it. They can design them to amplify sounds but that's as far as it really goes because the tiny, tiny speakers in the device can't be made much bigger. And the microphones at the other end of the spectrum can't keep up either. Its fantastic that they're able to do this well enough at all, but its still disappointing.