A lucency just means a dark area on the x-ray/CT as opposed to an opacity (which is a white area). I'm not sure what type of CT scan you got (i.e. with or without contrast injection), but don't jump to conclusions about it being cancer..... lucency just means a dark area on the x-ray/CT as opposed to an opacity (which is a white area). I'm not sure what type of CT scan you got (i.e. with or without contrast injection), but don't jump to conclusions about it being cancer.....
The operational details of amplifiers are buried in the field of electronics, but for audio purposes it is usually safe to say that current commercial audio amplifiers are so good that a normally operating amplifier is seldom the limitation on the fidelity of a sound reproduction system.
Powered Speakers. Here is where things can get muddied. A powered speaker is technically one that has its own amplifier built into the speaker, and therefore plugs into a nearby outlet. However, a powered speaker is not necessarily an active one, as the crossover components within a powered speaker can be passive.