Last updated: March 08, 2024Regarding setup, two things always pop up; line in and mic in. Most people lack the knowledge to tell the difference between these two.
They both differ due to different voltage levels. So, if you can’t tell the difference between them, you might damage your sound.
For starters, these are types of audio inputs that indicate your audio level voltage. Line-in can manage louder and stronger currents, while mic-in can handle low current levels.
And, of course, they both serve different purposes. So understanding their difference is critical for the best quality sound.
That’s why we have developed this guide to explain what separates these two from one another. So continue reading till the end and design your setups more effectively for the best results.
Sound flows in the form of voltage in your speakers, amplifiers, mixers, and various other audio interfaces. The levels of these audio signals can be high or low based on the current levels that your inputs are anticipating. This is where the difference between the mic and line level comes in.
Line in is the socket you will find on different audio interfaces, as well as some mixers and sound cards of computers. You can connect external audio devices, such as a mic or other instrument.
On the other hand, mic-in is only for microphones. You can connect a wired/wireless to your audio interface mic. This input is specialized for mics, and you can’t use a line-in.
Reading those manuals can seem a bit tough. But going through them will enable you to understand which devices go where in your audio interface.
For instance, several wireless receivers come with different output levels. So, if you go through the manual, you can connect them properly, and it won’t damage your equipment.
It includes signals from the source with 0 dB, requiring little to no amplification. For example, a mastered DJ mix is a good line-level signal as the sound is already loud enough, and you don’t need to add any gain.
You can process these line-level signals to good use. However, they are already loud, so you don’t need any extra amplification, and you can connect your speakers with a noticeable volume.
A mic-level signal from the source is -40 dBV (or less), resulting from the voltage level coming out of a mic when you place your mic in front of a sound source.
Mics record sound by converting changes in air pressure into wire current. These electrical currents are subtle, and you must use your mic preamp to record your vocals. When considering voltage, a mic-in signal is around a thousand times lower than a line-in signal.
There are a few things that you need to understand in this line in vs. mic in comparison. Line-level signals are around 1V or around a thousand times stronger than mic-level signals. But generally, these two signals don’t use the same input, and these signals travel from the pre-amp to your amplifier.
If you have a quarter-inch jack, an RCA, or even a 3.5 mm jack for your line-level input, you can use an XLR connector (female) for your mic-in input.
Regarding pre-amplification, line-in is the highest level in all audio products and can run at 1 Kohm (kilo ohm) compared to mic-in, which maxes out at 1 Kohm.
Mic-in is designed to handle the signal intensity at the mic level. That is precisely why you don’t hear an audible signal when you plug your mic into the line-in. In simple words, signal level can be understood as volume.
Mic-in requires more amplification, while line-in doesn’t require any amplification. If you are involved in recording, you should use a mic-in for connecting your mics and a line-in for connecting your instruments.
In most cases, line-in is associated with unbalanced audio, but it also supports balanced connections. You can distinguish between balanced and unbalanced audio if you look at the cable you use for recording or replaying.
There are two connecting points on unbalanced cables, like jack cables and TSR. On the other hand, balanced cables come with three contact points, like XLR cables.
There is a positive and a negative conductor on unbalanced connections. Balanced connections feature a ground as well as a positive and a negative conductor.
Both ground conductors work like shields to prevent electromagnetic noise and radio frequencies from entering the cable.
Line inputs have stronger signals than mic inputs, as they are made to handle line-level signals. These signals are a thousand times stronger than mic input signals in terms of voltage.
Therefore, they don’t need much gain. Hence, mic inputs amplify quieter sounds as they have a much higher gain capacity.
Some classic preamps have a separate gain knob for line and mic inputs. Both these knobs have different ranges. For instance, line inputs are usually limited to 20 dB gain, while mic inputs can add up to 80 dB gain.
In most cases, line inputs don’t come with any controllable gain or require any, as they are made to use with already amplified signals.
You must understand that you must connect a device with its correct input. This is because your setup has no technical tolerance for such a mistake.
Connecting your mic with a line input will result in very low or almost no sound. This is because the mic-level signal is weak and can’t handle the line input with a higher voltage.
On the other hand, if you connect a line-level signal with your mic-in, it will cause a lot of distortion and noise, and the output will be pretty loud.
Going mic to line-in won’t also work because the line-in signal is too powerful for the mic-in. Therefore, there is no option for you to use these signals and inputs interchangeably and get a good-quality sound.
To understand the difference between line and mic levels, you need to understand the four different audio signals you will have to deal with in the audio world.
We will talk about them in detail in the following text.
Standalone preamps, amplifiers, mixers, and in-line mic preamps, are common for boosting mic levels to line levels.
This boost ranges from 45 dB to 70 dB, depending on preamp quality. Those standalone preamps can be single or multi-channel, while mixers combine multiple signals to an individual output.
Inline mic preamps can boost dynamic mics to line level and work well with dynamic and ribbon mics. You can use them in podcasting and broadcasting.
You can connect line signals with mic input. The output can turn out loud and with plenty of distortion. Nevertheless, most of these line signals often peak at around 0 dB. So you won’t need any added amplification.
Consequently, if you connect your line-level signal to a mic input, you will get plenty of unnecessary sound artifacts. These may include crackling, ringing, and clicking sounds. So, the results won’t be as desired, and you will have to compromise your sound output quality significantly.
These in-line mic preamps produce an additional gain of around 20 dB for any sound source you are recording or reproducing using a cable.
Most of these in-line microphone preamps are for mics during live performances. However, you can use them to add more gain to your instrument signals that need a subtle pre-recording gain.
These in-line microphone preamps are more affordable than conventional mic preamps. But you will also have to compromise to gain control.
As they have a small size and durable design, you can use them in your live performances. On the other hand, conventional mic preamps are suitable for studio use because they are fragile and heavy.
Without using preamps, you can’t record high-quality, audible vocals. This is not just limited to music production but includes voiceovers and podcasts.
You don’t have to buy an expensive mic preamp to capture quality sound vocals. Just go for a mic-in to do so. Essentially, every mic-in is a preamp in one way or the other. However, external preamps are highly regarded for their sound quality and wider gain range.
Still, you don’t need to have them unconditionally. Vocalists only need a quality audio interface that they can use to create high-quality vocals.
As per the list above, an instrument-level signal falls right between the mic-level and line-level signals. Therefore, these signals need amplification to be at the line-in level.
You will work on these signals while recording instruments like bass or guitar. The signals are unbalanced and can result in noise if you are not using shorter cables with poor cables.
Instruments with pick-ups, such as bass or guitar, come with high-impedance signals. If you use them with low impedance, you will shave off a lot of detail from the result. You can sort this matter out using a quality active DI box.
These signals are all about post-amplification. These signals come when the line signals pass through the amplifier and into your speakers.
Speaker level signals are the loudest of all the four types, and they have more voltage than their lin-in counterparts. You have to make sure that you always choose quality speakers and cables to ensure excellent signal transfer.
Aux-in is close and a better option than others. Still, it is 0.3V, and the line-in is 1V, so you can use them interchangeably. These auxiliary inputs come from consumer products, including home theater systems and Bluetooth speakers.
These aux-in connections are always unbalanced, and you can’t use them for your microphone. On the other hand, Phono inputs are for turntables and record players. Direct signals from your turntable need a special equalization before going to the amp.
It’s partially because if your record has too much low-end, the needle will skip, and partly because it allows more time for recording. You will need RIAA equalization if you have an amp with Phono input.
With this type of equalization, your records will sound like HiFi audio. Some turntables have an option aux or line output with pre-applied equalization. Sometimes, these devices might come with a switch you can use to switch between aux or line.
This is because line-level signals are stronger than mic-level signals. Therefore, for the best results, you must raise the quality of the mic level signals to line level signals with the help of a mixer or a preamp.
You can connect a line-level signal with a mic-in, but there will be plenty of distortion in the output. With the help of an attenuator, you can reduce the line in quality. Some modern mixers do come with switchable mic/line inputs.
It is essential to match a device with its correct input, as there is no technical tolerance for any mistakes. Connecting a mic with the line level will make no sound, as the signal is weak. On the other hand, connecting a line-level source to the mic-in will result in louder sounds with high distortion as the line-in signal is much stronger.
