A passenger car driving by at 25 feet is about 60 dB, being next to a jackhammer or lawn mower is around 100 dB, a nearby chainsaw is 120 dB. Generally, 150 dB (eardrum rupture) is only achieved if you stand really close to a jet aircraft during take-off or you’re near an explosive blast.
If you actually wanted to intentionally kill someone with a sonic weapon, there isn’t a whole lot of research on how you would actually go about doing it. The general consensus is that a loud enough sound could cause an air embolism in your lungs, which then travels to your heart and kills you. Alternatively, your lungs might simply burst from the increased air pressure. (Acoustic energy is just waves of varying sound pressure; the higher the energy, the higher the pressure, the louder the sound.) In some cases, where there’s some kind of underlying physical weakness, loud sounds might cause a seizure or heart attack — but there’s very little evidence to suggest this.
So, there you have it: Sound can kill you, but not in the standing-in-front-of-a-giant-speaker-stack-at-a-gig.
