Whether you’re recording the next great true-crime podcast, working on a rock opera in the basement, or trying to get your record player hooked up to the same receiver as your television, it’s essential to know the difference between a line input and a mic input.
With the gadgets and connectivity that modern technology affords us, it can be messy figuring just what cords go where. This confusion is especially relevant for line and mic inputs. Keep reading for a short guide to help you know why and when to use each.
The Difference Between Line in and Mic in
In the simplest terms, a mic input is designed specifically for the signal from microphones. A line input design is for higher-powered signals from mixers and consumer electronics such as Blu-Ray players, MP3 devices, and smartphones.
While they seem similar, you need to know the difference to get the best performance from your equipment while keeping it from damage. To better understand when to use each, let’s take a deeper look at the differences between the two.
Power
The main difference between the inputs is the amount of power they support. Line inputs produce more volume than microphone inputs. A line-level signal is one volt, 1,000 times stronger than a mic-level signal. For this reason, plugging a microphone into a line input will be extremely quiet – if audible at all.
Alternatively, because a mic input handles much lower voltage, using mixers, instruments, or other audio sources into a mic input will overpower the equipment. The resulting sound will be too loud, to the point of distorting or damaging the equipment.
Mono vs. Stereo
Many microphones are directional, meaning their design picks up sound from a specific point while minimizing surrounding sounds. This directional ability comes in handy while recording in spaces where extraneous sounds are audible. Because of this design, mic inputs only use a single channel, making them mono.
Since the mic input is mono, any line-level signal plugged into the mic input will result in mono audio. This difference between mono and stereo is why using the line input is essential for mixers and receivers. Most media utilizes multiple channels for stereo and surround sound. The best movie and music experiences will come from the line input.
Connectors
Often mic inputs and line inputs have different connectors that can be helpful in discerning which to use. Generally, a line input will support three types of connectors: RCA, quarter-inch jack, or eighth-inch jack (also known as a 3.5 mm phone jack).
Mic inputs, particularly for recording purposes on audio interfaces and mixers, will have a female XLR input. On consumer-grade electronics, such as handheld recording devices and laptops, mic input connectors might also be quarter-inch or eighth-inch jacks.
Most products will take great pains to label their inputs properly. Always read the device’s instruction manual to be sure of proper use.
Purpose
It can be helpful to boil down any questions regarding line and mic inputs as a question of purpose. Ask yourself, what is this device supposed to do?
With few exceptions, microphone inputs are strictly for microphones. If there is no mic input on the device, the voltage can be modified for a line input. We will cover these techniques in the next section.
Since most devices need higher voltage and multiple channels, they generally require a line input.
Can a Line in and a Mic in Be Used Interchangeably?
In short, line inputs and mic inputs are not interchangeable. This incompatibility is due to the variance in the amount of power required for each. Resorting to using a mic input for a line-level device could distort your sound, damage your equipment, and cause harm to your hearing.
Using a microphone in a line input will create a barely audible signal. Turning up the volume will not solve the problem – it will amplify a noisy mic that still won’t be loud enough.
Modifying a Device’s Signal to Converting an Input
Fortunately, necessity is the mother of invention. Below are a few ways to modify your signal to use in its opposite input. These are handy workarounds for devices that have limited inputs. These also serve as creative ways to maximize the sound quality from minimum inputs.
Always consult the instruction manual for additional information on input and output specifications.
Using a Mic Input for a Line Input
Below are a few modifications that allow a microphone to work a line input.
Attenuator
Attenuators are electrical components that act as the middle man between your device and the input. They help maintain the integrity of a signal while reducing its overall power or amplitude. Attenuators come in several different shapes and sizes depending on the connector needed.
Direct Injection Box
Working in a similar vein to an attenuator, a Direct Injection box (also known as a DI box) helps connect high-level signals to mic-levels, usually through an XLR connector.
Additionally, these devices are helpful for those that wish to pursue audio engineering. They are common in recording studios and music venues because they minimize the amplitude of signals without additional devices, ensuring the sound is unaffected.
Using a Line Input for a Mic Input
Below are a few modifications that allow a microphone to work through a line input.
Mic Pre-Amp
A microphone pre-amp is the opposite of a DI box or attenuator as it boosts the level of a microphone to a line-level signal. While doing this, it also ensures that hiss and other forms of white noise often gained by cranking a microphone’s signal are kept at a minimum, ensuring a clear and true microphone sound.
A mic pre-amp is also a useful tool for recording artists and podcasters as it allows you to control the microphone tone. This control can help to bolster vocals and add warmth to conversations.
Mixer
A mixer is a very versatile audio engineering tool. It can be used to narrow multiple signals down to one output, which is very helpful when recording with multiple mics while only having a single input. A mixer enables a microphone to run through it and then out as a line input.
Mixers also allow for the use of microphones that require phantom power with line inputs. These microphones, known as condenser mics, are more sensitive to sound and require additional DC voltage to work. Without phantom power, these mics will not yield any sound at all. This makes having a mixer essential for any use of a condenser mic.
Final Thoughts on Line in vs. Mic in
Though they seem to do the same thing — and can even look the same — a line and a mic input are different parts of a device. To achieve the best sound, you should learn their differences to know which to use for your connectivity needs.
Always be sure to read your device’s instruction manual, especially if you’re ever in doubt about which input to use. Remember that sometimes the connector for both inputs can be the same.
After learning the differences between the two inputs, you’re now able to capture your creativity freely – even knowing how to work with input limitations.