What Do You Plug A Microphone Into?

Microphones plug into a variety of devices depending on the use case, the type of microphone, and whether the signal needs to be amplified, recorded, or reinforced. The type of mechanical connection, impedance, signal level, and whether the mic requires power all factor into what it can be plugged into.

Mixer and Mic Preamp

A microphone plugs into a mixer, specifically for the mic preamp to bring the signal up to line level, at which point an amp gives the signal more juice so it can drive the speakers. A dedicated mic preamp can be used if you have only one mic, but the flexibility of a mixer pays off when you suddenly need another mic. A mixer is particularly useful for PA and live performance applications.

Better quality microphones for PA and studio use use 3-pin connectors inside a metal shell about 3/4 inch thick — these balanced connections are often referred to as "XLR." These have a ridge on the female connector that has to line up with a slot on the male connector. They have a spring-loaded latch, so you push them together until the latch clicks. You will have to depress this latch to disconnect. Most microphones like this have detachable cords, and the cords can be daisy-chained together if you need a longer cable run.

Audio Interface for Computer Recording

To connect a microphone to a computer, you need an audio interface. Microphones produce an analog output signal, and their output levels are quite low. Condenser microphones, which are considered the superior type for studio recording, require external power. What is needed is:

• A power source for the microphone to operate
• A preamp to amplify its low output signal to a more healthy level
• An analog-to-digital converter to turn the analog signal into bits and bytes
• Some kind of digital interface (such as USB, FireWire, Thunderbolt) to deliver those bits and bytes to your computer

Audio interfaces cover all of those requirements. You won't find them in most computer stores, but you can buy them online or locally from any retailer of musical instruments. Stay away from the cheapest models; 200 dollars/euros is about the minimum for a decent audio interface. Good ones, which offer superior sound and better quality overall, start at about 400–500 dollars/euros.

Small audio interfaces abound that will accept from one to many microphones using XLR connectors, and then can be plugged into a computer using a USB (or FireWire) cable. The interface is a preamplifier, analog-to-digital converter, and may have controls and indicators for setting gain level, headphone output, and many have phantom power out. The mic plugs into the interface, and the output of the interface goes to the computer/laptop/phone.

Audio Interface Checklist

Here is a checklist of features to look for when selecting an audio interface:

XLR microphone input

At least one XLR microphone input; for stereo recordings you obviously need two.

Phantom power

Often labeled "P48" or "48V." This is a way of powering condenser microphones from the microphone input. It does not require any additional leads but uses normal XLR cables. Phantom power does not affect dynamic microphones that do not require external power.

Additional inputs

Line inputs for synthesizers, drum machines and other equipment with a medium to high output level. Instrument inputs are useful for guitars and basses.

Headphone outs

One or two headphone outs. When you record overdubs, you must use headphones and mute your speakers to avoid crosstalk.

Monitor outs and volume knob

Monitor outs for your speakers and a volume knob on the front panel. If your audio interface comes without monitor outputs and a volume knob, you have to get an external monitor controller at additional cost.

Digital port compatibility

Make sure your audio interface comes with a digital port (such as USB) that is compatible with your computer. Most audio interfaces require a dedicated driver to be installed on your system.

Computer Interface Types

When selecting an audio interface, the type of computer connection matters:

• USB 2.0 — The most common interface to add peripherals to both Windows and Macintosh computers. USB 2.0 is not the fastest protocol, but its bandwidth is sufficient for small to medium sized interfaces. These are by far the most common and also the most cost effective models.
• Thunderbolt — A very fast protocol, but common only on the Macintosh platform. Thunderbolt is a fairly expensive technology; just a cable is 40–50 dollars/euros, and Thunderbolt audio interfaces usually come without a cable.
• FireWire — Outdated and not recommended for new purchases.
• USB 3.0 — Much faster than USB 2.0, but there may be compatibility problems since it is a fairly new technology for audio interfaces. USB 2.0 audio interfaces do not always work well on USB 3.0 computer ports (which usually have a blue plastic insert), at least on the Windows platform.

Bus-powered audio interfaces draw all the power they need from the computer they're connected to. Bus power, especially on USB 2.0 interfaces, does not deliver very much energy, often at the cost of audio quality. Bus powered audio interfaces rarely deliver true P48 phantom power — quite often the voltage is too low or the available current insufficient to power a condenser microphone properly, which could result in increased noise and/or reduced audio quality. Therefore, it is recommended to get an audio interface with its own power supply.

USB Microphones

Manufacturers have integrated basic electronics into microphones so that the mic can be plugged directly into your computer, getting required power over the USB connection. Some of these have built-in headphone jacks and level controls. These USB mics can be of pretty good quality, have a built-in desk stand, and don't cost a lot.

The first thing you may notice is that microphones come with a large three-pin output plug unlike anything you'll find on a laptop or desktop computer. There are mic to USB adapters, but this seemingly simple solution won't unlock the true potential of your microphone.

Amplifiers and PA Systems

A microphone can also be plugged into an amplifier or PA system. Some situations may call for plugging your mic into a guitar or bass guitar amplifier — for example, if you are in a jam space without a PA system, or looking to add crunchy distortion and other effects to your vocals.

When going back to home recording on tape from the 1950s, many decks came with microphones that connected via permanently installed cords ending in a tip-ring plug. These might be 2.5mm, 3.5mm, or 1/4 inch in diameter. The 1/4 inch models could be plugged into a guitar amp and used as vocal mics. The plug simply pushes into the jack — you may feel a few spots where it engages spring-loaded connectors, but you simply push it all the way in.

Some newer microphones of the "condenser" style need voltage to operate, both to energize the electret and often to run an active amplifier stage. This "phantom power" can usually be turned on or off at your device. Such a mic can be plugged into the mixer of a PA system.

Condenser Microphone Power Requirements

Condenser microphones require external power to operate. Phantom power (around 50 VDC) is supplied by your input device or an outboard power supply. If phantom power is left on, it will not damage dynamic mics because of the way the pins inside the plugs are set up. The beauty of phantom power — a Neumann invention — is that it does not require any additional leads but uses normal XLR cables.

In summary, your mic has a cable and needs to be plugged into a recorder, amplifier, PA system, or computer that is suitable for the type of cable and type of mic. That device will have to have power, and its level controls will need to be set to meet your needs — sufficient gain without being too loud or getting feedback.