Hey I am a layperson, and have very little understanding of physics. I'm trying to understand the relation between a magnetic field and air and how they are similar or dissimilar in terms of disturbance in them. Let me lay out the context from which I came to think about the question. Electric guitars use magnets to detect the vibration in the guitar strings. These are called "pickups" as you probably know. From Wikipedia I learn that they are called transducer magnets. So these magnets are a variable reluctance sensor that captures or senses mechanical vibrations from stringed instruments such as the electric guitar". So, the magnet detects the movement of the electric guitar strings and then translate that into electric signal. This signal goes into an amplifier and converted back to sound by vibrating a speaker. Fine. I understand the mechanism in theory. So what is the relation between movement in the air (which cause the sound heard acoustically) and movement in the magnetic field (which is what the pickup detects)? To elaborate, if I play an E note on an unplugged guitar I hear the sound because the string vibrates and move the air, which is then detected by my ears. Now I am plugging in the guitar and that same sound is being projected through a speaker. The movement in the air created the same sound. So, when the magnet picks up the string movement what it is picking up? If it is picking up the disturbance in the magnetic field created by the strings then why exactly it is the same thing as the disturbance in the air? If the question is not clear I will try to further clarify. But for now I'll wait for answers. Thanks a lot in advance.