Line level facts for kids

Line level is a way to measure how strong an audio signal is. Think of an audio signal as the electrical message that carries sound, like the music from a CD player or the sound from a video game console. This signal needs to be at a certain strength so that other devices can use it properly.

Line level signals are much stronger than signals from a microphone, which are very weak. A strong line level signal can be sent to an amplifier. An amplifier then makes the signal even stronger, powerful enough to make loudspeakers produce loud sound.

What is an Audio Signal?

An audio signal is an electrical wave that carries sound information. When you record your voice or play music, the sound is changed into an electrical signal. This signal travels through wires or wirelessly to different devices.

Different Strengths of Audio Signals

Not all audio signals have the same strength. They come in different "levels" depending on where they come from:

• Microphone level: This is a very weak signal, usually just a few thousandths of a volt (millivolts). Microphones produce these signals when they pick up sound.
• Instrument level: This is a bit stronger than microphone level. It's what you get from electric guitars or keyboards.
• Line level: This is a much stronger signal, usually around 1 volt. It's the standard strength for connecting most audio equipment.

Why is Line Level Important?

Line level is important because it's the standard strength for connecting many audio devices. Imagine trying to talk to someone across a noisy room. If you whisper (like a microphone signal), they won't hear you. If you speak normally (like a line level signal), they will.

When you connect a CD player, a DVD player, or a game console to a stereo system, they usually send out a line level signal. This signal is strong enough for the stereo's amplifier to work with it without adding extra noise.

How is Line Level Used?

Line level signals are used to connect many different types of audio equipment.

• From source to amplifier: Devices like CD players, MP3 players, and mixing boards send out line level signals. These signals go into an amplifier.
• To loudspeakers: The amplifier then boosts the line level signal. This super-strong signal is then sent to loudspeakers, making them vibrate and create sound you can hear.

What is a Preamplifier?

A preamplifier is a special device that helps with audio signals. Its main job is to take a very weak signal, like one from a microphone, and make it stronger. It boosts the microphone signal up to line level.

Why do we need Preamplifiers?

You need a preamplifier when you want to connect a microphone to equipment that expects a line level signal. Without a preamplifier, the microphone's signal would be too weak. The amplifier wouldn't be able to make it loud enough, or the sound would be full of static and noise. Preamplifiers make sure the sound is clear and strong enough to be used by other audio devices.