The term 'SPEAKER BOOSTER' is a combination of two words, 'SPEAKER' and 'BOOSTER'. A SPEAKER is an electronic device that converts electrical signals into sound waves, while a BOOSTER is an electronic device that amplifies the signal. The term 'SPEAKER BOOSTER' is often used to refer to a preamp, which is an electronic device that boosts the signal from a microphone or other audio source before it is sent to a SPEAKER. Preamps are typically used in recording studios and live sound reinforcement systems.