I have a few sound science questions related to speaker voice coil and magnet. I have been told that speaker sensitivity is mostly determined by how "strong motor" the voice coil and magnet together are. Some other aspects also affect speaker sensitivity (like weight of the moving mass), but the biggest factor to sensitivity is the strength of the motor. At Least, this is what I have been told by hifi enthusiasts, I don't have education on this subject, so please, feel free to correct the previous statement if needed. Here are my sound science questions: *Can someone please edcate me on the differences of voice coils and magnets (meaby by comparing different kind voicecoils and different kind magnets)? *What are the very basics when calculating voice coil and magnet related properties (focusing on those calculations that help me understand the strength of the motor and sensitivity of the speaker)? *Is there a "gain and lose thing" when thinking the strength of the motor (for example, would making stronger motor possibly effects negatively to some other measurable aspect)? Right now, all I know about voice coils is the basic working principle, and, the more rounds around the voice coil the bigger the resistance for an amplifier. In your answers, I would be very happy if you could go into very detailed answers about speakers individual parts and how they interact with each other. Outer dimensions, shape, mass, width of gap for coil, material composition, and magnetic properties are some of the factors I'm assuming play a role in making "a powerful motor", and I would be very happy to know more about this complicated subject. Meaby my questions are somehow related to headphones, but I'm mostly looking information related to speakers. If you have headphone specific info of voice coils and magnets, feel free to share that too. And if you have in your browser's bookmarks some good and educational web links related to the topic, please share those too. if you choose to participate in the debate or answer my questions, I would really appreciate it.