Acoustic energy means: The unmistakable vibe someone gives off when they're operating with zero irony and full heart - the kind of presence that's warm, earnest, and completely undefended. People with acoustic energy. There is no real cause for parental concern; it is descriptive vocabulary rather than risky behaviour. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.