These systems all use **electro-mechanical feedback loops**…

These systems all use **electro-mechanical feedback loops** that create **self-resonance** as the primary sound production method, allowing rich audio generation without traditional input sources. The key is the **AGC component** that sustains low-level signals traveling through the resonant medium, preventing the system from taking the "path of least resistance" (direct speaker-to-speaker feedback) and forcing it through the intended resonant body.