What Next?
Dave Barratt - BT Age and Disability Action
We have been looking at the past, in what we mainly have talked about, amplification, inductive couplers, adjustable ringers and flashing lights. But what is coming next? What can we expect to come to help?
We have spoken about digital induction couplers. Although people have their doubts whether they will work, or have not yet seen them, so we do not know.
We have spoken about Bluetooth and then we have smarter amplification. That is something that in our research development side we have been looking at.
Fig. 1 Speech levels showing how hearing loss reduces the range available
Fig. 1 shows frequency along the bottom, with the sound level up the side. The bottom line is the normal hearing threshold below which we cannot hear anything, and above the 100 mark it is going to be painful to our ears and may well distort.
The telephone service fits quite nicely to the middle to upper range of that pattern. So, with a normal hearing person such as myself, I would hope I could hear with no problem. However, if we introduce a hearing loss, anything below that line we can no longer hear, so we are missing out parts of the audio signal.
Fig. 2 The effect of compression in making the full range of sounds available.
When you boost the signal up as in Fig. 2, if you look at the audio signal now, it has gone above the uncomfortable level. So not only have you now -- will you not be able to hear the lower tones now boosted up. The higher tones are causing problems, discomfort or maybe distortion.
We have been looking at this to see how can we get over the problem and make it so that the upper level does not cause a distortion or discomfort?
What we then do is to compress the signal. You can see from that compressed audio signal now that we have utilised what area we had left of useful hearing to actually put all of the hearing in there. So we have taken the distortion, the painful levels, down. In effect, we have amplified whatever level we required for our own individual purpose.
This is all well and good, but what happens to it? Do we put it in a telephone? Do we put it on a network? There are pros and cons for all of this. One of the main things is we are all individuals, and we have all got probably different hearing losses.
If you put it in a telephone, how would you be able to select the one that is best for you? How would you know whether your audiogram has got a high or low loss? It is a bit difficult. I am not sure how we are going to do that, but it is development.
What we have is a network-based solution. This is only a trial that we are looking at, but we are looking to dialling a number, a prefix, before you dial your main telephone number. The prefix will give you your own individual settings of amplification and compression.
The benefits are that maybe at home you have a telephone that works fine. You go to a hotel or somewhere like that, and they have not got the telephone that is suitable for you.
With this system, you would be able to dial the number that suits you. Your compression would go in and then you would be able to use their telephone with that adjustment of compression.
We are at a stage now where we want to try this. We want to see if there are any general settings. Maybe 5, 6, or 7 that fit quite a few people.
We have made the telephone so you can adjust that level. It may be you go to your phone, a big button one, or a new one. You go away, use the same setting. Because the characteristics are different, you may need to alter that. Using the buttons on the telephone, you will be able to alter the compression, the amplification and something called "slope", which is too technical for me but I am sure some of you guys will understand.
So you can adjust what is best for your own hearing needs. There is not a great deal of amplification in our network that we can put in without getting echo suppression and other problems. If we can get the signal so that the clarity is better, your hearing aid will be able to use that clarity to give you a better signal.
If you do not use a hearing aid, just getting the greater clarity will also give you a better signal, and enable communication.
That is what we are looking at within our amplification side. We are not looking at doing it linearly, which is to move the whole lot up. We are looking at specific parts of the frequency range that we can amplify. How we want to amplify, what level, and tailor it is for yourself to decide.
The only rider with this, I am afraid, is that this work is under development. There is no guarantee it is going to lead to anything. We have got a system running and we want to try it out, but we can say the learning we have taken from that we will use to provide better communication.
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