You need a microphone (How to choose a mic), an instrument (guitar, voice, …), and a computer to put it all together and get it on YouTube. A lot of people gloss over the microphone to computer bit in their minds though, and are suddenly left unsure how to go about connecting the 2.
That’s where the audio interface comes in. What exactly is an audio interface and what is an audio interface used for? Well read on!
A simple audio interface definition:
A device that allows your computer to understand what your instruments are saying.
Another way to define audio interface is that it is a sound card for your computer, that also allows you to mix, playback, and master music.
What Is An Audio Interface Used For?
Audio interfaces have 4 main functions:
- Provides appropriate inputsoutputs
- Provides “Phantom Power” if needed
- Converts analog signals to digital
- Controls audio latency
Audio Interface Inputs and Outputs
You have probably noticed that there is no TRS jack on your laptop to plug your bass guitar into. Similarly, there is no XLR jack for your microphones.
You need some way to transfer the Audio from your mics to your computer via some sort of Interface device. Get it? I crack myself up.
You can get audio interfaces that have anywhere from 1 to 100 inputs. The more inputs they have, the more expensive they are. While you can get away with only 1 input, I strongly recommend that you have 2.
If you ever plan on playing an instrument and singing at the same time, you need 2. It is possible to get away with only one, but you it will greatly increase your frustration and the time it takes to get a high quality finished recording.
With only 1 input you have to record every part of the song individually and then sync them back up later with software. While this is something you might want to do anyway because it can produce a better recording, it is very difficult to do it without a reference point.
I want to record a song where I sing and play acoustic guitar. I have 2 inputs on my audio interface and make 2 recordings. 1 where I focus on playing guitar perfectly, and 1 where I focus on getting the singing perfect.
Then when I go to my computer and merge the 2 recordings, I can simply line up the vocal tracks from each one. I merge them together and keep the good tracks from each recording, discarding the rest.
Many audio interfaces these days have “combo sockets” on them. Audio interface combo sockets allow you to plug both XLR and quarter inch cables into them.
Audio Interface Provides Phantom Power
If you use a condenser microphone (Learn about microphones here) then you need to provide it with “Phantom Power”. Phantom power is simply a low voltage power source that the mic needs to work correctly.
Audio interfaces generally provide that phantom power for you. This function is sometimes referred to as a microphone preamp.
Audio Interface Signal Conversion
When you play an instrument or sing a song, you hear the resulting sound waves. Sound waves are an analog signal and look like this:
As I’m sure you’ve heard many times, computers think in 1’s and 0’s. They don’t understand the wavy analog signal, and need it broken down into a digital signal like this:
Audio interfaces do this conversion for you. Even if you use a USB microphone or have some special way to plug your guitar into your computer, somewhere along the line the signal is being converted from analog to digital.
In the case of the USB microphone, the computer it is plugged into is doing the conversion. This is fine most of the time, but it does put an extra tax on the computer. With an audio interface the burden of conversion is handled away from the computer, and frees it up to handle more difficult mixing tasks.
Audio Interface Latency Control
Audio latency is defined as the time it takes for the sound to leave your mic or instrument and enters the audio interface until it comes out a speaker.
If your audio interface has a latency of 9ms, then from the time your guitar is play until you hear the sound in your headphones 9ms will have passed.
This timing is important when trying to play or sing. Anything more than 10ms and you will be able to hear the delay and have trouble staying in sync.
Most modern audio interfaces have very small latency times, just make sure you check it out if you happen to be thinking about buying a really cheap audio interface. You usually get what you pay for, and it’s usually a good idea to get the lowest latency audio interface you can.
Recommended Audio Interface
The best affordable audio interface that I have used is the Focusrite Scarlett 2i2 USB Recording Audio Interface.
It usually costs around $200 (though it’s on sale at the moment for $150), and is best used when recording a song with vocals while playing the guitar.
It has 2 microphoneinstrument combo jacks, and connects directly to your computer via USB. There are monitor speaker jacks on the back.
I really like the fact that I can plug my headphones into it and it sends the monitor audio directly to the headphones. Since the monitor audio doesn’t have to come from the computer, there is 0 latency.
The Scarlett 2i2 has a 24-bit resolution at sample rates of up to 96 KHz. This means that your digital output is of very high quality and every nuance of your performance is captured and recorded.
It comes with nice software, and will work on both AppleMacintosh and PC computers.
The best cheap audio interface I’ve found is the Behringer UM2 Audio Interface. It sells for around $45. This one only has 1 input though. It will get you by, but I strongly recommend one with at least 2 inputs.
If you want one that is between the 2, you could go for the Focusrite Scarlett Solo. It goes for $100. It has one XLR jack and one instrument jack. This means you can have a mic and a
guitar plugged in at once, but not 2 of either.
Hopefully I answered the question “What is an audio interface used for”. Just remember that when looking for an audio interface for your home recording studio you need to think about 5 things:
- Number of inputoutput jacks
- How many microphone preamps it has
- If quality software drivers are included
- If you can connect to your computer (DAW) via USB
- That it has low latency.
Figure out your needs and pick one up. Audio interfaces are extremely easy to setup. Before long you will be creating professional sounding music videos for your YouTube channel, and creating a huge following.