You are concentrating too hard on SPL
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Mike, that what determines the intensity of sound. I don't know what you mean by 'sound energy'. The full acoustic energy? The energy per unit volume? The flow of energy per unit area? It's very hard to compare apples to apples unless we agree on what we compare and definitions. The SPL is a standard value, it has units, it can be measured and can be compared.
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Cup your hand and smack your ear. Hurts like hell doesn’t it? But yet there is no sound.
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What is it then? By smacking you ear you created a high SPL sound wave. At a high intensity you don' hear it as a 'sound' but rather it feels like pain, since the SPL exceeds the pain threshold. It' the same idea behind "concussion" grenades. By the way, the term 'percussion ' grenade refers to the old type of grenades that explode on impact. They are not used anymore, instead timed fuses are used.
From Wikpedia:
The percussion grenade detonates with impact. Timed fuse grenades are usually preferred because percussion grenades could explode while being carried. Some percussion grenades have a slow fuse as a backup ignitor. Some militaries have also created and used percussion grenade guns in the past.
