Using sound in self defense? Is this real or is this BS? Good question! First lets take a look at sound and the human body.
Back in 1997 my oldest son and I went to a Metallica concert in Detroit Michigan. Now aside from the fact that the show was AMAZING, there was a sign at the entrance to anyone who is pregnant that they would not be allowed in and their ticket refunded.
The heavy BASS in the their show could cause a person to go into labour. Therefore sound affects the body!
Have you ever listened to music and felt great after or during? How about feeling BAD or ANGRY? Certainly! Yep, there are people insist it cannot be used for any purpose. They are just closed minded!
Many Aikido masters insist O-Sensei used sound in his works. I have no doubt he did!
Personally I have been able to use if very effectively in many situations in the dojo. I have not personally tried in on the street, because I tend to want to avoid those situations! I have had enough of them to last me a lifetime!
Now for the non believer, you are right because you will always get what you believe, what your personal limits are, so ROCK ON!
For the rest of us, if the idea of using sound in self defense holds any interest to you, then pursue it! I do have a little video on the topic of sound and colour you may find helpful. But if not that is cool too!