How to choose speaker magnets?
We all know that the speaker inside the speaker equipment, is responsible for the core important parts of the sound, the speaker is a transducer device that converts electrical signals into acoustic signals. The performance of the speaker has a great impact on the sound quality.
What is a speaker magnet?
A Horn magnet, also known as a horn word, is used in the speaker horn inside the magnet.
The speaker magnet working principle
When the speaker receives the electrical signal output by the sound source device, the current will pass through the coil on the speaker and produce a magnetic field reaction.
The current through the coil is alternating current, and its positive and negative poles are constantly changing; the positive and negative poles meet to attract each other, and the coil is attracted by the magnet on the speaker to move backward; the positive and positive poles meet to repel each other, and the coil moves outward.
This rhythm of closing and expanding will produce sound waves and air currents and emit sound, which is the same effect as the throat vibration of speech. The magnet in the speaker is used to make sound, without this magnet, the speaker will not make a sound.
How to choose speaker magnets?
Alnico is the earliest magnet used for speakers, such as tweeters. Generally made into internal magnetic speakers.
The disadvantages are low power, narrow frequency range, hard and brittle, and very inconvenient processing. In addition, cobalt is a scarce resource, and the price of alnico is relatively high. From the point of view of cost performance, the use of Alnico for horn magnets is relatively small.
Ferrite magnets are generally made into external magnetic horns. Ferrite magnetism is relatively low and requires a certain volume to meet the driving force of the horn. Therefore, it is generally used for louder audio speakers. The advantage of ferrite is that it is cheap and cost-effective; the disadvantage is that it is large in size, low in power, and narrow in frequency range.
NdFeB magnets are far superior to Alnico and ferrite and are the most used magnets on speakers, especially high-end speakers.
The advantage is that under the same magnetic flux, its volume is small, power is large and frequency range is wide.
The selection of speaker magnets to consider several factors
1, need to clarify the ambient temperature of the speaker work, according to the temperature to decide which magnetic material to use. Different types of magnets have different temperature resistance characteristics, and the maximum working temperature they can withstand is different. When the working temperature of the magnet exceeds the maximum working temperature, there may be magnetic energy decay, demagnetization, and other phenomena, which will directly affect the sound effect of the speaker.
2, we must consider the magnetic flux demand and magnet volume to choose speaker magnets. The loudspeaker magnet is not the louder the better. From the impact of magnet performance on the sound quality of the speaker can be seen, the magnetic flux of the magnet has a great impact on the sound quality of the speaker. We need to consider the volume of the speaker on the magnet volume limitations and the requirements of the permanent magnet flux performance.