Speaker magnets, as the name suggests, are magnets used on speakers, and are an important accessory on speakers, as well as the driving part of generating the sound.
How it works
The speaker magnet becomes an electromagnet when the electric current changes into the speaker. The direction of the current is constantly changing, and the electromagnet also keeps moving back and forth, driving the paper cone also vibrate back and forth, generating the sound. This is the principle of the speaker’s sound.
Image Source: Hookeaudio & Audiofanzine
Magnets In a Speaker
Speaker magnets on the market are mainly ferrite, alnico, neodymium iron boron magnets. Ordinary ferrite magnets are generally mainly used for low-grade headphones. Neodymium iron boron magnets are used for high-grade headphones, such as first-class sound quality, good sound quality detail performance, good vocal performance, and accurate sound field positioning.
Image Source: Hsmagnets
Alnico Magnets | Alnico magnets are the earliest speaker magnets, such as tweeters in the 50s and 60s. Generally made into internal magnetic speakers. The power is small, the frequency range is narrow, and the sound quality is hard and very brittle.
Ferrite Magnets | It is made of magnetic material powder and iron powder material at about 1200℃. Generally made of external magnetic speakers, Advantages: cheap, highly cost-effective. Disadvantages: larger size, smaller power, narrower frequency range.
NdFeB Magnets | As powerful speaker magnets, their performance is far better than ferrite magnets, currently the most used magnets on the speaker. In the same volume, magnetic strength is generally more than 10 times the magnetic strength of ferrite magnets. Its characteristics: the same magnetic flux under its small size, high power, and wide frequency range. The current HiFi headphones basically use such magnets. Disadvantages: With the price of rare earths increases, the price of NdFeB magnets has also soared.
| NdFeB Magnet | AlNiCo Magnet | |
| Density (D) | 7.5g/cc | 6.9-7.3g/cc |
| Electrical Conductivity (r) | 150 | 45-70 |
| Remanence (Br) | 1.0-1.4 | 0.6-1.4 |
| Coercivity(Hcj) | 750-2000 | 275 |
| Maximal Energy Product (BHmax) | 200-440 | 10-88 |
| Advantages | Resistance against demagnetization | High Curie temperature |
| Small-size magnet | Resistance against corrosion | |
| Disadvantages | Vulnerable to corrosion | Brittle |
| Low resistance against demagnetization |
Magnets' Effects on the Speaker Sound Quality
The better the speaker magnets, the greater the magnetic flux density B, and the stronger the thrust acting on the cone. Magnetic flux density B (magnetic induction intensity): in a magnetic field perpendicular to the direction of the magnetic field of the energized wire, the magnetic field force F with the current intensity I and the product of the wire length L IL ratio, the formula for B = F / (I * L).
The greater the magnetic flux density B, the greater the power, and the higher the relative sensitivity of the headset. Headset sensitivity: pointing to the headset input 1mw, 1khz sine wave, the headset can be issued by the sound pressure level (sound pressure in dB, the greater the sound pressure, the greater the volume), so the higher the general sensitivity, the easier the headset sound.
Image Source: Quora & Amazon
The higher the magnetic flux B density, the lower the total quality factor Q of the speaker.
Q (quality factor) refers to the speaker damping factor of a group of parameters. Q value is divided into Qms, Qes, and Qts. Qms for the mechanical system of damping, reflecting the movement of various parts of the speaker in the absorption and consumption of energy, Qes for the damping of the electrical system, mainly in the voice coil DC resistance to the consumption of electrical energy. Qts is the total damping.
The greater the magnetic flux density B, the better the response speed. Headphones with fast response should respond immediately to the signal and stop when the signal stops.
Specifications of Ferrite Magnets for Speakers
The speaker magnets are mainly disc magnets or ring magnets. The coating of the speaker magnet is generally zinc. But according to environmental protection and many other requirements, eco-coatings are also available. Here are some specifications of ferrite magnets for reference.
| Type | D | d | H |
| YH0005 | 7.5 | 1.2 | 1~15 |
| YH0006 | 7.5 | 3.2 | 1~15 |
| YH0010 | 8 | 3 | 1~8 |
| YH0011 | 8 | 4 | 1~8 |
| YH0012 | 8 | 4.2 | 1~8 |
| YH0014 | 8 | 2.1 | 1~8 |
| YH0015 | 8 | 2.9 | 1~8 |
Image and data source: Itacamagnetics
| Type | D | d | H |
| YH0001 | 5 | 0 | 1~10 |
| YH0002 | 5.2 | 0 | 1一10 |
| YH0003 | 6 | 0 | 1~8 |
| YH0004 | 6.35 | 0 | 1~15 |
| YH0007 | 7.5 | 0 | 1~8 |
| YH0008 | 8 | 0 | 1~8 |
| YH0009 | 8 | 0 | 1~8 |
| YH0013 | 8 | 0 | 1~8 |
| YH0016 | 8 | 0 | 1~8 |
Image and data source: Itacamagnetics
The quality of the speaker magnets is one of the important factors affecting the sound quality of a speaker. The purchase of headphones should pay attention to this.
Speaker Magnets Provider: Tengye
At Tengye, we’re thrilled to be early participants in your new projects. Our passion for magnets extends from material selection and design optimization to providing magnetic solutions. We hope to bring our knowledge and experience to the forefront by actively engaging in your upcoming projects.
