How Speakers Create Different Sounds
Geposted von JiangDavid am
Speakers can play many types of music and sounds. They work by changing electrical signals into vibrations, which create sound waves. The process happens in these steps:
1. Electrical Signal Input
A sound source (like a phone, computer, or amplifier) turns music or voice into an electrical signal. This signal is an alternating current that keeps changing. These changes control the pitch, loudness, and tone of the sound.
2. Creating Vibrations
When the electrical signal enters the voice coil, it creates a magnetic force. This makes the voice coil move, which shakes the diaphragm and pushes the air. Different signals make the voice coil move in different ways:
Different frequencies → Different pitches
• High-frequency signals make the voice coil vibrate fast, creating high sounds (like a violin or bird song).
• Low-frequency signals make the voice coil vibrate slowly, creating deep sounds (like drums or thunder).
Different amplitudes → Different volumes
• A strong current makes a strong magnet, which moves the voice coil more and creates a louder sound.
• A weak current makes a weaker magnet, which moves the voice coil less and creates a softer sound.
Different waveforms → Different tones
• A smooth sine wave makes a soft, clear sound (like a flute).
• A complex wave (with mixed frequencies) makes rich tones (like a human voice or piano).
3. Sound Waves Travel Through the Air
As the diaphragm moves in different ways, it pushes the air to create various sound waves. This is how speakers produce different types of music, instruments, and voices instead of just a simple "hum."
Electrical signals control how fast, how strong, and in what way the voice coil moves. This decides the pitch, volume, and tone of the sound, allowing speakers to play all kinds of audio.
How do speakers amplify sound?
In broadcasting, meetings, speeches and other scenarios, we often need to amplify sound so that more people can hear it. The key to amplifying sound in a loudspeaker is that the amplifier provides more current to drive the voice coil to produce vibrations of greater amplitude, which drives the diaphragm to push more air, ultimately creating stronger sound waves, allowing sound to travel farther and louder.
1. Signal Amplification
Sound signals (such as microphone sound or radio signals) are very weak. In order for a speaker to produce a louder sound, these signals are first amplified by an amplifier (power amplifier) to increase the strength of the signal.
2. Driving the voice coil to vibrate
The amplified electrical signal enters the voice coil of the speaker. The voice coil vibrates in a magnetic field and moves back and forth according to the current. The stronger the current, the greater the vibration of the voice coil.
3. Drive the diaphragm
The voice coil is connected to the diaphragm of the speaker, and when the voice coil vibrates, the diaphragm vibrates with it. When the voice coil vibrates, the diaphragm vibrates with it. The vibration of the diaphragm pushes more air.
4. Producing a louder sound
The air pushed by the diaphragm creates sound waves, which are transmitted to our ears. When the signal is amplified, the voice coil vibrates more, pushing more air, and the sound becomes louder.
Types of Speaker Enclosures
Speakers come in many designs, each with unique features that suit different needs.
Bass Reflex (Ported) Enclosure
This is one of the most common speaker designs. It uses a special opening (called a port) to let sound waves from inside the box escape. The size and shape of the port affect the deep bass sound. This design makes bass stronger, but if not done right, it can cause distortion.
Sealed Enclosure
A sealed speaker has no ports or openings. It keeps air trapped inside, which helps control vibrations for a cleaner sound. However, it requires more power to produce strong bass. This design is great for clear and tight sound, especially in high-quality audio systems.
Passive Radiator Enclosure
This design adds an extra, non-powered speaker cone (called a passive radiator) to help boost bass. When the main speaker moves, the passive radiator reacts to increase low-frequency sounds. It improves deep bass but may not respond as quickly as other designs.
Isobaric Enclosure
This type of speaker uses two drivers (speakers) working together to create stronger bass. They are usually placed face-to-face or in a special arrangement to increase low-frequency output. However, if not carefully designed, the sound may become unbalanced.
Transmission Line Enclosure
This design uses a long internal tube to guide sound waves and extend bass response. The longer the tube, the deeper the bass. However, this can also slow down the bass response, making it less suitable for fast, punchy sounds.
Horn Enclosure
Horn speakers use a flared shape to amplify sound and send it farther. They are often used in concerts and outdoor events because they can project sound over long distances. However, they are not the best for deep bass.
Loaded Horn Enclosure
This combines a transmission tube with a horn shape to improve bass response while still projecting sound far. It is ideal for large, high-energy audio systems that need powerful, far-reaching sound.
Compression Enclosure
This design places two speaker cones facing each other to push air and create deeper bass. The sound is released through tubes or openings. It can produce strong low-frequency sounds, but the design must be precise to avoid sound imbalances.
Each speaker design has its own strengths. Some focus on deep bass, others on clear sound, and some on long-distance projection. Choosing the right design helps create the perfect sound system for any need.
Conclusion
Speakers convert electrical signals into sound through electromagnetic induction and magnetic field interaction. Different frequencies determine the pitch, while different amplitudes affect the volume. A power amplifier boosts the signal, making the sound louder and clearer, enhancing the overall audio quality.
