Speakers are an indispensable part of our auditory experience, converting electrical signals into the vibrant sounds we perceive. Speakers are widely used in various electronic devices that produce sound and are common and indispensable products. However, even the seemingly simple speaker still requires an understanding of how it operates and how it affects the complexity of sound production. It is necessary to delve into its underlying mechanisms and key components. This article will provide a comprehensive overview of the use of speakers in audio design, including their basic operations, key specifications, design considerations, types of cones and magnets, etc., as well as the product features of speakers launched by Same Sky.

The operating principle and technical specifications of the speaker

    The sound generation of a loudspeaker involves the precise interaction between electromagnetic and mechanical movements. It begins with electrical signals, which are the representation of the audio we want to hear. This signal can come from various sources, such as smartphones, laptops or any other device capable of generating audio.
    Inside the speaker, the key components start to function. The core components are the voice coil and the permanent magnet. The voice coil is made of wire and is connected to a flexible cone or diaphragm. The voice coil is surrounded by a sturdy permanent magnet, laying the foundation for sound production. When an electrical signal flows through the speaker's wires, it energizes the voice coil, initiating a series of actions controlled by electromagnetism. This kind of electrical energy generates a magnetic field around the coil, whose polarity is consistent with the change of the electrical signal.
    The essence of speaker operation lies in the interaction between these magnetic fields. As the magnetic fields fluctuate, they alternately repel and attract, driving the voice coil and the connected cone to oscillate rapidly. The oscillating motion interacts with the surrounding air molecules, causing them to vibrate synchronously with the movement of the cone. These vibrating air molecules generate pressure waves, which travel through the air and eventually reach our ears in the form of sound.
    Before introducing the basic knowledge of speaker operation and structure, we need to first understand the various key specifications and performance standards that need to be considered when designing and choosing speakers.
    Firstly, the measurement unit of sound pressure level (SPL) is decibel (dB), which is used to measure the intensity of sound waves in the air, that is, the loudness of sound. The sound pressure level is affected by factors such as the distance of the sound source and environmental conditions. Sound pressure level is also an important parameter for evaluating noise levels in various environments, ranging from industrial Settings to residential areas, providing valuable information for noise control and regulation.
    The measurement unit of the maximum input is watt (W), which is the maximum power that can be used for an extremely short period of time without permanently damaging the speaker. The measurement unit of nominal input power is also watt (W), which is the power that the speaker can safely handle during long-term use.
    The measurement unit of impedance is the Ohm (Ohm), which is the resistance to the current flow in an amplifier. A lower nominal impedance value indicates that the speaker consumes more power. It is important to match the speaker impedance with the impedance compatible with the amplifier to ensure optimal performance and prevent potential damage to the equipment. Matching impedance also helps to achieve effective power transmission and maintain the fidelity of audio reproduction.
    Resonant frequency refers to the frequency at which a speaker vibrates most effectively, and its measurement unit is Hertz (Hz). The resonant frequency specification provides a rough way to compare the low-frequency responses of different speakers. In addition, the frequency range is determined by the size of the speaker. Smaller speakers operate best at higher frequencies, while larger speakers perform better in lower frequency ranges. Low frequencies are used for deep bass, while mid frequencies are used for speech reproduction.
    The total Q value refers to the Ile-small value and can be used as a broad reference for determining the ideal box type. A total Q value of 0.4 or lower indicates that the speaker is most suitable for the ventilation box. If the total Q value is between 0.4 and 0.7, it is recommended to use a sealed box. A total Q value of 0.7 or higher indicates that the speaker is suitable for free air, semi-open or unlimited baffle Settings. However, there are exceptions to these criteria, and it is very important to evaluate all relevant parameters.

Speaker size, shape, installation and testing precautions
    Generally speaking, speakers with a larger surface area will produce a higher sound level under the same driving signal and have a better low-frequency response. The use of DSP predistortion can significantly enhance the performance of small speakers. This technology is typically employed in the design of mobile phones and laptops. A small amount of performance enhancement can be achieved by designing the shell on the back of the speaker.
    The shape of the speaker cone is usually determined by the available installation space. An elliptical speaker cone allows a larger surface area of the speaker cone to be placed in a non-square space. The frequency response graph of the speaker should be inspected to determine whether the size or shape of the speaker has an adverse effect on the expected performance of the speaker.
    As for the connection configuration, there are multiple options for the speaker, depending on the application requirements, including wires, through holes, pads, etc. In addition, speakers can be equipped with various protection levels (IP) to handle moisture and contaminants in harsh environments. On the other hand, speakers do not have a service life rating because they can provide reliable performance for many years when used within the rated specifications.
    After selecting the speaker using the above key specifications, several additional speaker measurements and tests can be carried out to ensure that the speaker is correctly integrated into the design and meets the specifications.
    First, the frequency response can be tested. This is the visual representation of audio components in reproducing the audible sound range. Step frequency scanning is similar to frequency response, but is specifically designed for aliasing frequencies to obtain a more comprehensive frequency response.
    On the other hand, the test level and gain are also quite important. The level is the key to determining how much energy the device can output, and the gain is the measured value of dividing the device's output level by its input level. In addition, the total harmonic distortion plus noise (THD+N) also needs to be measured. Harmonic distortion is the addition of unnecessary new tones in the audio signal. THD+N is a convenient and persuasive single digital performance that is widely understood and accepted.
    Phase measurement is used to describe the positive or negative time offset of the periodic waveform measured from the reference waveform within one period. The two most common measurements are the input/output phase of the device and the inter-channel phase (for multiple speakers in the system). Friction and humming are used to test the speaker, which can detect the presence of high-frequency harmonic products generated in response to low-frequency stimuli.
    The Thiele-Small value is used to capture the complex impedance of the speaker under test and provide the calculated electromechanical parameters, which define the low-frequency performance of the speaker driver. The Thiele-Small results (including the total Q value) accurately describe the interaction between the speaker and the housing, which is crucial for both the design and production testing of the speaker system. Speaker impedance is a measure of the resistance a speaker has to the flow of alternating current (AC) signals, such as audio from an amplifier. It is measured in ohms and represents the resistance of the speaker to the electrical signal.
    The frequency response curve is quite important for speakers. The term "response" indicates a speaker's ability to reproduce the input frequency. When drawing these data, it will form a frequency response graph, which visually represents the relationship between the amplitude generated by the speaker and the frequency. The vertical axis is marked with the level of sound, with the unit of decibels (dB), and the horizontal axis is marked with the frequency, with the unit of Hertz (Hz).

Select the ideal speaker cone and magnet materials
    The type of material used for the speaker cone and other factors will all affect the sound quality. Evaluating this through listening and experimentation is more accurate than relying solely on numbers and data. The durability of common cone materials is also an important factor to be considered. Generally, plastic is the most durable, followed by paper and cloth, and then foamed materials. However, the actual lifespan of a speaker depends on factors such as humidity, environment and application details.
    Speaker cones made of plastic are widely popular due to their durability and resistance to environmental factors such as dust and water. They are also easy to manufacture and have precise tolerances, thus having better performance in reducing distortion and sound quality. Plastic diaphragms can rapidly absorb and dissipate mechanical energy, demonstrating excellent damping characteristics similar to those of traditional paper cones. Although usually referred to as plastics, these materials consist of various composite materials, and their costs vary depending on factors such as thickness, pressing technology, size and temperature resistance.
    Paper and cloth cones are renowned for their excellent sound quality and self-damping, but they may be affected by humidity. They are made of various wood fibers and additives such as cotton and wool, mixed to achieve specific sound characteristics. This mixture enhances the intensity and compensates for the weaknesses, thereby generating different sounds. Because of their light weight, they are mainly used in large speakers.
    Foamed materials are rarely used as the sole material for diaphragms and are usually mixed with other materials such as metals, plastics or paper. In the composite diaphragm, foaming materials are added to the interlayer. Its main function is to enhance internal loss, which is a key physical characteristic of the speaker.
    High internal loss helps to minimize the inherent sound characteristics of raw materials to the greatest extent. For instance, the internal loss of metal diaphragms is relatively low, making them prone to generating metallic sounds. On the contrary, paper cones have a higher internal loss, thereby generating a more natural sound with the least impact on the timbre of the raw materials.
    Another key component of the overall structure and performance of a speaker is the type of magnet. First of all, ferrite magnets, also known as ceramic magnets, are low-cost magnets that can maintain their magnetic strength very well. They are very heavy and are usually not used in applications that require portability. Speakers equipped with ferrite magnets will have better sound quality when approaching their maximum processing capacity. Ferrite magnets are also very suitable for applications in humid environments because they have natural corrosion resistance.
    AlNiCo magnets were the first type of magnets used in speakers, which help speakers produce smooth and classic tones. Speakers with alnico magnets are more expensive than those based on ferrite, but they are less likely to break. These magnets are surely not as common as neodymium magnets (NdFeB) nowadays, but they can still be used in high-end applications that require precise tuning.
    Neodymium magnets, also known as rare earth magnets, can provide the highest magnetic field strength among all known permanent magnets. Speakers made of neodymium magnets have good frequency response, are lightweight, and are much smaller than those using ferrite or alnico magnets. This makes them ideal magnets for small speakers that need to output high sound pressure levels. The main drawback of neodymium magnets is that they are more prone to breakage.
    Samarium cobalt (SmCo) magnets are used less frequently than other types of magnets due to their higher cost. Their main advantages are corrosion resistance and stable output under extreme temperature changes, making them highly suitable for harsh environments. They are prone to breakage and not as strong as neodymium magnets. However, cost remains their biggest drawback.

A complete series of speaker products in various specifications
    The speaker products of Same Sky can be provided with frame sizes ranging from 10 millimeters to 205 millimeters and sound pressure levels ranging from 72 to 135 decibels, offering quality and convenience that meet customers' sound requirements. The speaker options of Same Sky include various frame shapes, magnet types and installation methods, which can quickly match the customer's design. Same Sky can also customize speakers suitable for customers through some mechanical and electrical modifications.
    The speaker types launched by Same Sky include micro speakers and standard speakers. To conform to the trend of miniaturization, Same Sky offers a series of micro speakers with compact package sizes as small as 10 millimeters and depths as low as 2 millimeters. The sound pressure level of the micro speakers of Same Sky is 72 to 135 dB, the impedance ratings are 4, 6, 8, 16, 20, 25, 32 or 50 ohms, and the resonant frequency is as high as 1700 Hz.
    As a leading force in the industry, Same Sky's standard speakers are designed for high power output and reliable performance, with package sizes ranging from 41 to 205 millimeters. The standard speakers of Same Sky have a sound pressure level of 78 to 107 dB, a resonant frequency of 50 to 3000 Hz, and rated impedance of 4, 6, 8, 16 or 32 ohms.
    Same Sky offers various cone types, magnet types, frame shapes and installation methods, enabling customers to easily find speakers that meet their design requirements. In addition, a variety of tweeter models are provided, as well as medical speakers specially designed to meet the regulatory standards of IEC 60601-1-8 and in accordance with the requirements of medical alarm signals. Same Sky also offers audio design services that can assist engineers in conducting crucial speaker measurements and tests. Look for the speaker that suits your needs at https://www.arrow.com/zh-cn/manufacturers/cui-devices/audio-components/speakers.
Conclusion
    Understanding the mechanism of speakers enables engineers to create an immersive auditory experience. This article introduces a variety of components and specifications, which can assist customers in choosing the right speakers. However, even with a deeper understanding of the key speaker parameters, it is still necessary to combine it with the correct testing and measurement of the selected speakers in the final design. The full range of micro speakers and standard speakers launched by Same Sky can meet the diverse needs of customers. Meanwhile,     Same Sky's audio design service can also provide additional assistance to customers!