Carole, No you are not crazy nor are a great many others that have been diagnosed as such. Modern science and medicine have no explanation for the changes that are taking place in all things, and most often refuse to admit or accept what is right in front of them.
I am not aware of any studies that have been done accordingly because it has to do with unaccepted scientific theories, however we are on the threshold of a new age and if you look at the current data it is quite simple really to formulate the most probable hypothesis. So let's do that but it is going to require some reading.
Let's start with Quantum Physics which has shown us that all matter is made of energy. For a wonderful explanation of this and for those that have not seen it, please see;
http://www.whatthebleep.com/rabbithole/So all matter is energy and our thoughts have the power to create which means that we must be able to transmit and receive energy or signals like a radio, but a more appropriate definition would be like a radio crystal.
As you have stated most people consider this impossible, yet has also been proven that some people can hear microwaves. And also agree that as you receive energy it can have thermological and acoustical effects on your biology.
However there is something much larger happening that most are unaware of, if you read the following article about DNA and light you will come to understand that DNA is susceptible to changes from light or energy;
Are humans really beings of light?With this knowledge let's look at something else that has yet to be connected to the above findings. I love this article because of the description of Gamma Rays as packets;
Gamma-rays, like visible light, are made up of packets of energy called photonsThe above link comes from this page that has links to much more information about Gamma and other radiation;
http://www.astronomycast.com/astronomy/ep-136-gamma-ray-astronomy/However we must give NASA credit for this discovery and all those pretty pictures we've paid for;
http://www.nasa.gov/mission_pages/GLAST/news/gr_pulsar.htmlSo from all of this we can safely postulate that we are receiving signals from the universe, that is changing our DNA so that we become the light beings that we are, of which telepathy is but one of our many inherent abilities.
That is if our fellow beings of light that are playing the bad guys in this production don't cause us to vacate our physical bodies before we become what we are.
Hope this answers more of the questions. However I don't think you will be able to get away from the hum, unless of course it has nothing to do with Gamma Rays.
If you care to share more about what you are currently experiencing with the voices and sounds of the crowd, I am very interested and would love to hear all about it either here or via PM. Although I'm certain that there are many others here that would love to know as well and could most probably relate to your experiences.
Also there is data referencing what you are now experiencing and actually indicating this time period as the beginning of this phenomenon, according to the data you are not alone as many will be experiencing the same thing. There will also be time based anomalies, as we become aware of alternate dimensions. Once again time permitting as per those playing the bad guys. Unfortunately I am unable to post that information here due to applicable copyrights.
In truth there is nothing to fear as this is the illusion and the all encompassing universal energy of which we are all a part of is the infinite reality.
Blessings, B
Engineering Balance.