What is Mic vs. Line Level? Signal Levels Explained.

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In this video, I explain the difference between mic and line level signals with a special edit from our Live Sound Essentials course. We also discuss two additional signal levels used in live sound.

As the signal travels all the way from the mic to the speaker, it goes through the signal chain. And in that chain we can alter the strength of the signal, which is what we call boosting or cutting Gain.

We can boost or cut Gain with a preamp, with EQ, with a fader, or with almost anything - actually almost every audio device will be able to boost or cut Gain in some way. But different devices use different SIGNAL LEVELS, and each of these has a purpose.

First of all, we have mic level. Microphones output a pretty low signal. And that's just because the mechanics of a microphone don't generate that much power. Remember, it's a transducer and it's changing a soundwave into an electrical signal, and that's not necessarily a super efficient process.

But we have mic level coming from the mic into the console. And the very first thing the signal hits is the microphone preamplifier, which we usually just call a mic pre, or preamp. This adds Gain to the signal, and the level is controlled by a knob called Gain, or Trim. Now, this knob's very important and I go through tons of tips on how to set it later on.

But as the mic pre adds Gain, the signal is boosted from mic level to line level. And this is what most of the audio system is going to use. In most cases, after the mic pre everything will stay line level until it gets to the speaker system.

Of course, like most things in audio, there are some exceptions. Some DJ mixers or small analog mixers might have mic level outputs. Or, some powered speakers might have mic level inputs. Or, there could be a switch on the back of a wireless receiver that lets you choose between mic and line level.

So, you just need to make sure that as you're connecting 2 pieces of equipment, you know which type of signal you're using. Because, if you send a line level signal into a mic input, you might be clipping almost immediately. Or, if you plug a microphone into something that's expecting a line level input, you won't really hear anything - the signal will be way too low.

Also, there is some gear that falls in between mic and line level. This is mostly instruments like guitars and basses - so we call it instrument level. This is especially true with vintage instruments that have passive pickups. They don't really put out a solid line level like a keyboard, but it's definitely stronger than a mic.

Now, all of these signal levels are fairly low compared to speaker level. Speaker level is the strongest signal we have in audio. And that's the whole point of an amplifier - it takes a line level signal and amplifies it to a speaker level signal, which has a ton more power.

Speakers need this super strong signal to work. Big systems pull tens of thousands of watts of power. But it's the only way to get our small line level signal to a really strong signal that can actually make speakers move.