# Matrix

Could someone tell me what the matrix is and how it factors into HA programming. No reason other than my curosity.

Unfortunately, no one can be told what the Matrix is. You have to see it for yourself…

Seriously though, it usually looks like this: 126/50/5.

The first number is the peak output of the hearing aid. The second number is the gain (and frankly that’s the most useful number to talk about). The last number of the matrix is the rise in the curve in dB between 500 Hz and the first peak on the graph.

If you want to geek out, here’s an article:

http://www.hearingreview.com/issues/articles/2003-11_01.asp

In the old days, a hearing professional could literally look in a catalog of matrices and pick one they wanted to go in a custom hearing aid. So they could basically write the lab and order up a CIC with a 114/40/10 matrix in a Class D, and the lab would do that. Each matrix had its own fitting range and a range of hearing aids it could physically fit inside.

Fast forward a couple of decades and it’s very different today. With digital hearing aids the exact frequency response of the aids, along with other characteristics like maximum power output, compression etc, even the fitting algorithm can be software simulated and adjusted.

So in this day and age when a hearing professional is ordering a hearing aid, he or she is likely to suggest the gain of the hearing aid based on the loss and how much headroom they want for future deterioration, and that’s probably the only number in the software they will look at. In Starkey fitting software for example, as standard the only options are Standard, Power and Extreme Power. There are several matrices behind the scenes and the lab would rather just get an idea of what the hearing professional is looking to do, and they will pick the appropriate power of amp based on loss, device type and other factors.

Experienced hearing professionals can switch that into advanced mode in the preferences and will be allowed to select the specific gain they are looking for. But no matter how experienced they are, few will care about anything other than the gain number on the matrix.

Thanks for the link ZCT, very interesting.
Even though I am retired, I guess I’ll die a tech head.