Benefits 16 channel vs 8?

Hi, while I’m new here I’ve been on boards for years and I hope it’s ok if I jump right in with my questions. I’ve done a lot of reading here and elsewhere and haven’t found answers to these questions. I have a very professional audiologist and a relative is an audiologist. I’m looking at the Unitron, which is owned by the Dainish firm, Sonova Holdings. The latter also owns Phonak.

I’m told Unitron gives more bang for the buck in terms of features.

I’m also looking at the Zon on the recommendation of my relative audiologist. My audi called my relative who is 1,000 miles away, and we talked on the speaker phone. She wound up saying the unitron would be fine and not to worry about the water proofing issue. I didn’t get to ask her the question I’m asking here. She’s a long time audi with a nursing degree and works in her husband’s office. He’s an ENT. They don’t sell aids.

The question my audiologist couldn’t really answer is, given that an 8 channel Unitron costs $3,000 and a 16-channel $4,000, what is the marginal benefit of the 16 over the 8? What is the percentage improvement in performance, etc. Is it worth it. He says the 16-channel gives him the ability to tune the aid better.

Thoughts?

@Khenkels said:

This is what my Audi told me too. The more channels helps her fit better.

I have to take issue with this overly simplistic view of the situation. Now sure, your audiologist may have ‘dumbed it down’ for a patient, but I don’t really accept that this is true.

For starters, a really thorough hearing test considers results at 250Hz, 500Hz, 750Hz, 1000Hz, 1500Hz, 2000Hz, 3000Hz, 4000Hz, 6000Hz and 8000Hz. That’s 10 different frequencies. If it were truly critical to a good fit to alter the frequency output at 16 frequencies, wouldn’t a test typically include a test of 16 different frequencies?

Next, we need to consider the issue of bands. These split the channels down further to provide more fine tuning.

Finally, at least for this answer, we need to consider how adjustable each channel is. If you get a 16 channel aid and adjusting one channel affects maybe 1-4 other channels when making adjustments, then you don’t truly have the flexibility of certain other aids. You also need to consider what adjustments can be made with each channel, along with a massive variety of other factors.

To put it in other terms; can you state unequivocally, that a eight cylinder engine is ALWAYS better than a six cylinder engine? Is American NTSC television that updates 60 frames per second superior to European PAL television that updates 50 frames per second?

There is so much more to a hearing aid than how many channels it has.

You only need 4 or 5 compression channels, according to the researchers.
(Compression changes the real-time non-linear behaviour of the aid in a frequency region)

There are however sometimes also equaliser style bands overlaid on the core compression channels.

These extra-fine gain adjusters are useful for:

• profiling unusual audiogram shapes more accurately than usual
• notching out frequency resonances which seem to feedback too much
• notching out fixed environmental frequencies: for example if you work in a gas turbine hall

The other advantage of fine bands is that the automatic noise reduction software can adjust the gain and noise reduction algorithm and also the directional microphone steering for each frequency. So, the more bands the more chances you have of quieting frequency specific noise sources.

One point: a hearing aid has to filter frequencies using banks of digital filters in software. These filters cannot say stop 100% of all sound below 1100 Hz and allow 100% of sound between 1100 Hz and say 1200 Hz, and then block 100% of sound above 1200 Hz. Filter have ‘soft’ edges not right angled edges.

This means that if you boost the gain drastically at a certain narrow frequency you will either ‘drag’ the neighbouring bands with you or possibly the fitting software will simply prevent your dragging the gain bar too far away from the neighbours.

bandwith refers to the frequency response to a hearing aid,
most telefones for instance goes to about 5,000 (please someone correctme)
most high ends (Oticon, Siemens, even rexton and widex) goes to about 10hz,
while 10hz is not tecn measured, the benefits of such frq. range are now obvious.