Are my hearing aids “maxed” out?

I was adjusting the sound of my patient’s hearing aids recently when he asked me if they were “maxed” out. He said if they weren’t he wanted them to be.

What I told him is what I am explaining to you today in this article as to some basic differences between something called gain and volume. Gain is one of the harder terms to define, mainly because it’s used in a lot more places than just the audio world. Quite simply it means an increase in some kind of value. So for example, you can have a power gain, voltage gain, or current gain; and they all increase those respective values. Typically when referring to gain, we refer to transmission gain, which is the increase in the power of the signal. This increase is almost always expressed in dB (decibels). This could be the increase in the raw signal from any source into any microphone before it goes into any of the other electronic components. such as a hearing aid circuit.

Volume is scientifically different. Besides defining three dimensional space, volume can also be used to describe the power level of a signal. So when you turn up the “master volume”, it simply means you’re increasing the amount of power used by the amplifier in the electronic circuit to increase the signal. This term is quite ambiguous since it’s used in so many different places, mainly to mean the actual sound you perceive in your ears. I am going to try and simplify this is just a paragraph or two but first there is another term I want to add to the mix.

This term is “level” and is used to describe the magnitude of the sound in reference to some arbitrary reference. More specifically we use SPL (sound pressure level) to describe sound waves. SPL is a term calculated from the log of the sound pressure of a measured sound related to a reference value. Basically meaning we create a measurement scale with zero starting at the lowest threshold of human hearing. The SPL scale is shown in decibels or dB and goes up to 130 dB, which is the threshold of pain for the human ear. Sounds could be much louder than 130 decibels. A 747 jet plane takes off at about 175 decibels, etc.

Here is my attempt to make this simpler. I call gain the intensity of the sound signal, volume; the amount of power affecting that intensity, and level then the measurable score or tracking of both the gain or the volume which brings us back to my patient’s question and desire. I set the gain in the hearing aids with the fitting software from my laptop connecting to the hearing aids. Most times that is now a wireless connection but can be done with very small cables. The patient cannot change the gain ratio which is essentially the “benchmark” of sound programming. He can only change the volume.

Most hearing aids have between 35 and 55 decibels of gain ability which translates into between 85 to 142 decibels of volume sound. My patient wanted his hearing aids louder, but when I raised the gain, which was only about 75% towards being maxed out, it was way too loud for my sound power hungry friend. It was far better to give him a slightly modified gain upon which he could adjust the volume to his satisfaction.

Yes , the gain can be maxed out and the volume could then also be turned up to the maximum. In about 99% of all the patients I have ever helped, the gain is far from being maxed out. Needing more volume? Check with your hearing professional about an adjustment to a current hearing test.

If you have the symptoms of hearing loss let a professional help you find out why. The hearing professional will help you sort out the technology level to meet your need, your budget, and answer your hearing need questions.

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Jeff Bayliff, NBC-HIS, is owner of Hear the Birds Hearing Aid Center, Lock Haven, PA

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