Magnets play a crucial role in the functioning of speakers. They create a magnetic field that interacts with the voice coil, which is attached to the diaphragm. When an electrical current passes through the voice coil, it generates a varying magnetic field that causes the diaphragm to vibrate and produce sound waves. Thus, magnets enable the conversion of electrical signals into audible sound.
As this may lead you to believe, bigger magnets do not always equate to better speakers.
High Voltage Magnets
Loudspeaker voice coils produce an alternating magnetic field when AC voltage audio signals pass through them, and this interacts with magnet arrays either side of the speaker diaphragm to move it and generate sound directly proportional to its frequency.
Protecting speakers’ conductive coils from metal objects is essential to avoid interference and damage to other parts of the speaker, including overheating or shorting out of their components, which could negatively affect sound quality production. This interference could potentially cause overheating or shorting out, and may hinder its quality as well.
Larger magnets produce more electromagnetic current in response to an electrical input, which enhances speaker sensitivity and its ability to convert power into sound. A higher sensitivity typically means greater volume and clarity. Bigger magnets tend to result in lighter yet more powerful speakers; Neodymium-Cobalt magnets are the most commonly used materials due to their superior remanence/coercivity but still being relatively lightweight compared to their alternatives.
Ferromagnetic metals are materials which naturally attract magnetism. Iron (or ferrium) is one of the most frequently encountered ferromagnetic elements today; it forms the core of steel alloy used for everything from city construction to car manufacturing and machine repair. All ferromagnetic materials possess two magnetic poles: north and south polarities that attract each other while those possessing identical poles repel each other; for this reason you should never place speaker magnets near magnetic items such as nails, screws or wires as this could cause them to become magnetized over time and possibly impair how your speakers perform over time.
Alnico and ceramic are two popular ferromagnetic materials used for speaker magnets. Neodymium magnets have recently emerged as an alternative, becoming increasingly popular among modern moving-coil dynamic speakers. Although more expensive than both ferrite and alnico, neodymium offers superior performance over both, while also producing pink, purple, blue, and yellow compounds which over time may compromise sound quality.
Neodymium is one of the world’s strongest magnets. When combined with iron and boron, it forms incredibly strong permanent magnets which are widely used across industries including cell phones, earbuds, hard drives, automobile components and hybrid/electric vehicle motors – even small neodymium magnets can help identify counterfeit money!
Speakers containing neodymium magnets use what’s called a magnetostriction core made up of thin magnetic plates stacked together. When audio signal passes through a stationary coil, it generates an ever-varying magnetic field that causes these plates to change shape ever so slightly and produce sound waves, moving a diaphragm and producing soundwaves.
Up until recently, speaker designers had limited choices when selecting magnet materials for speaker systems. Alnico provided lower cost but larger size and weight restrictions than ceramic or ferrite options while ceramic proved good performance but more expensive. Neodymium offers the ideal balance of strength, cost efficiency and light weightness – the 21st-century solution to speaker design dilemmas!
Samarium Cobalt Magnets (SmCo), introduced in the 1970s, are an extremely strong rare-earth magnet with high Curie temperatures and coercivities that resist demagnetization – making them a suitable alternative to Alnico magnets when temperature stability is key. They contain less iron than their neodymium counterparts which makes them corrosion resistant without needing protective plating.
Samarium cobalt offers excellent resistance to heat, making it ideal for use in motors, sensors, automotive applications and miniaturization requirements. Like Alnico magnets, samarium cobalt requires special care in handling. Like other rare-earth magnets, however, it must be handled carefully; eye protection should always be worn when working with it and inherent cracks should be considered when designing assemblies with it. Machining can be accomplished using abrasive grinding techniques; however using coolant may minimize heat fracturing as well as fire risk from oxidized grinding dust oxidized dusts accumulated from such operations.