What is the Difference Between a Hearing Aid Band and Hearing Aid Channel?

What is the Difference Between a Hearing Aid Band and Hearing Aid Channel? The ability to understand speech is the prime function of a hearing aid. Human speech centers on frequencies between 250 Hz to 6000 Hz. By amplifying the speech frequencies and filtering out the non- speech frequencies which contain noise, speech is more understandable. Hearing Aids do this by working with bands and channels
First, let's look at hearing aid bands. Bands are just like stereo equalizers. They are used to control volume at different frequencies. This allows us to adjust more volume in a specific area of your hearing loss without affecting other areas where you might need less volume.
Let's take an example of an audiogram from someone with severe high frequency loss. For the red line, which is the right ear, at 2000hz we would need to add 20 decibels of gain to get that frequency to a normal range. At 4000hz we would need to add 45 decibels of gain to get that frequency to a Normal range. At 8000hz we would add 55 decibels of gain to get that frequency to a Normal range. This is how hearing aid bands increase specific frequencies where you need it—in the areas that you have hearing loss.
Now let's take a look at hearing aid channels. Channels split up the frequency range into individual groups. This allows the hearing aid to differentiate noise from speech. For instance, the sound of keys falling on a table, or water running in the sink, or walking on wood floors, these sounds are too loud they can be overwhelming. When your hearing aid offers multiple channels we can adjust each frequency that is too loud without sacrificing the things you want to hear, like the voice of your spouse or grandkids.
For example, an aid with 4 channels might be setup as follows:
Channel #1 250hz to 750hz
Channel #2 750hz to 1750hz
Channel #3 1750hz to 4000hz
Channel #4 4000hz to 8000hz
Within each channel you can control the intensity or amplitude of that channel, how the hearing aid boosts soft sounds more than loud, or limit the sounds at a certain peak or threshold.
Some new hearing aids can come with 24 channels or more... and have a price tag of 2 to 3 thousand dollars. And one might assume that more channels or bands will equate to better performance or more benefit. But is that actually true?
Starkey, a hear aid manufacturer, did a study involving 1,156 audiograms. Their goal was to determine how many independent channels were needed to maximize speech audibility. Their initial assumption was that a well-designed hearing aid is designed to maximize sound quality and speech understanding- -- and this was measured by how sharp or clear words sounded to a hearing aid wearer. The results of the study may surprise you. They found that the most significant improvement occurred within the first four channels. In other words, the greatest improvements were seen in people moving from one channel to two, two channels to three, or three channels to four. Some improvements were also seen moving from five to six channels, but it was such a small improvement that is was considered to be statistically insignificant. Beyond six channels they were unable to show any improvement in how clear the words word at all.
So if 95% of a person's hearing losses can be handled by a hearing aid with 4 to 6 channels, and there is no additional benefit from more channels, why spend more?