Sensory issues

This is actually more complex.

Just one environment can make changes and the noises/music can become drastically harsh. A music system, or TV or anything broadcasting, depending on the quality of cables, quality of the speakers, positioning and what they're bouncing off of, these all affect sound and how the human ear receives the signal. Things are changed about all the time in shops, in open spaces, in packaged ingredients, in lighting and even the chemicals used to clean bathrooms. Changing the structure of anything can affect sound. Even outside, over time things corrode or like trains and busses, break pads start screeching and companies are too lazy or don't even consider these might need fixing/oiling. One thing to note is now shops and outdoor lighting have fitted LEDs, they may not have changed the wiring or components like drivers, which is crucial to proper fitting. And components which are meant to work with halogen now lit with LED will make a high pitch excruciatingly irritating non-stop sound. 

But another thing mentioned here, is as we grow, we take on more responsibility, we incorporate more complex navigation into our being. A baby might be completely focused on holding a thing or walking. But once competent with one try doing both and so on. So when younger, he may have been putting energy and focus to make an effort to shut out sounds or not know the need to express discomfort. We can get lost in the moment and forget a thing happened seconds ago and then it's gone and we can forget again. 

Honestly, the thing which is important is that you recognise he is sensitive to sound and probably needs ear defenders. That sensitivity may not ever go away. I work in sound and get paid to be sensitive to frequencies and harmonics and all kinds of elements involved. This kind of ability is actually amazing for safety, as well. The inability to dull our senses was noted mid last century by psychoanalysts. It's never changed and just a cool, unique feature of autistic-wiring. 

This is actually more complex.

Just one environment can make changes and the noises/music can become drastically harsh. A music system, or TV or anything broadcasting, depending on the quality of cables, quality of the speakers, positioning and what they're bouncing off of, these all affect sound and how the human ear receives the signal. Things are changed about all the time in shops, in open spaces, in packaged ingredients, in lighting and even the chemicals used to clean bathrooms. Changing the structure of anything can affect sound. Even outside, over time things corrode or like trains and busses, break pads start screeching and companies are too lazy or don't even consider these might need fixing/oiling. One thing to note is now shops and outdoor lighting have fitted LEDs, they may not have changed the wiring or components like drivers, which is crucial to proper fitting. And components which are meant to work with halogen now lit with LED will make a high pitch excruciatingly irritating non-stop sound. 

But another thing mentioned here, is as we grow, we take on more responsibility, we incorporate more complex navigation into our being. A baby might be completely focused on holding a thing or walking. But once competent with one try doing both and so on. So when younger, he may have been putting energy and focus to make an effort to shut out sounds or not know the need to express discomfort. We can get lost in the moment and forget a thing happened seconds ago and then it's gone and we can forget again. 

Honestly, the thing which is important is that you recognise he is sensitive to sound and probably needs ear defenders. That sensitivity may not ever go away. I work in sound and get paid to be sensitive to frequencies and harmonics and all kinds of elements involved. This kind of ability is actually amazing for safety, as well. The inability to dull our senses was noted mid last century by psychoanalysts. It's never changed and just a cool, unique feature of autistic-wiring.