What Is An Audio Interface?
An audio interface is a piece of hardware that connects your microphone, guitar, or other audio equipment to your computer. The typical audio interface takes the analog signals that these sources produce and converts them into a digital signal that can be read by a computer.
It then takes that signal and sends it to your computer via a connection/output. Some of the more common connections are FireWire, Thunderbolt, USB 2.0 or 3.0 or a PCIe card.
The audio interface also takes this process and reverses it sending the digital signal from the computer, and converting it back into an analog signal so you can hear what is being recorded on the computer through your studio monitor speakers or headphones.
Most audio interfaces have line level inputs and outputs, microphone pre-amps for vocal and instrument mics, and some even come with digital inputs for digital instruments and MIDI enabled sound sources.
Why Do You Need An Audio Interface?
There are several reasons for using an audio interface instead of your computer’s sound card. Technically speaking a sound card is an audio interface but it is extremely limited. Here are some of the limitations.
- Limited sound quality and inputs and outputs.
- Only one consumer grade stereo line level input.
- Only one consumer grade stereo line level output.
- One consumer grade headphone output.
- They are prone to electromagnetic and radio interference.
- They have severe latency problems when recording and playing back through the monitors.
- It is impossible to record more than 2 sources at a time.
Sound cards are great for hooking up a couple of external speakers or doing basic podcasting, but if you want real production quality audio then you absolutely have to have an audio interface.
What Do You Want To Record?
When deciding on buying a an audio interface the most important question you need to answer is what do you want to record. Answering this question will determine how many inputs and outputs you need. It will also determine what type of inputs and outputs you will need.
Line inputs are the most basic type of input. They will connect other electronic devices like mixing consoles, DVD and CD players, synthesizers, and other electronic equipment.
Microphone inputs on the other hand are a little more complicated. The signal that comes from a microphone is very weak. It needs a pre-amplifier in order to produce enough signal equal line level inputs and then be converted into a digital signal.
Some microphones even need a power supply called phantom power in order to operate. That has to be part of the audio interface input for microphones as well.
If you already have a mixing console, then some of these considerations are not necessary because your mixing board will handle it. You only need to connect your mixing board to your audio interface.
However if you are starting from scratch with your home studio or recording set up, then you might consider just having the audio interface handle the mic inputs and eliminate the need of the mixing board.
Audio Interface Buyers Guide
Now that we have gotten you to start thinking about what you need and the options available to you, now it is time to go into our audio interface buyers guide. With all the options and all the different needs, it is no wonder that people need a guide to help them understand all there is about audio interfaces.
So let’s get started.
Choosing The Right I/O (Input/Output) Configuration
The term I/O is just geek speak for Inputs and Outputs. The amount of inputs and outputs you will need entirely depends on what type of recording you are going to do.
So if you are just going to do a podcast, then you might only need a small 2 channel audio interface, However if you are going to record music, especially with a band, then you are going to definitely need a larger interface.
Understanding The Audio Inputs
There are 5 different types of inputs to consider.
- Microphone Inputs: As I mentioned earlier, microphones send out a very low signal strength. You will need microphone inputs if you are gong to record vocals or use microphones to capture instrument sounds.
- Mic Inputs With Phantom Power: Condenser microphones need a power supply in order to operate. If you are going to record vocalists using a condenser microphone or are going to use a shotgun microphone for recording at a distance, then you will need to make sure that some of your audio inputs have phantom power.
- Instrument Level Input: Guitars and other instruments send more signal than microphones. These are sometimes called “high Z” or high impedance inputs.
- Line Inputs: Are you going to be hooking up a mixing board? How about a synthesizer or use background music while you are doing an intro for a podcast? Then you need some line inputs to connect those devices.
- Digital Inputs: We now live in an age where technology has come to the point where there are digital mixing boards and many keyboards and guitars can come with a digital output. You can connect these instruments with a digital connection.
Understanding The Outputs
Excluding the computer connectivity outputs which we will discuss below, most audio interfaces come with 3 outputs.
- 1/4 Inch Line Outputs: These outputs will connect your audio interface to your headphones, mixing board, or powered monitor speakers.
- RCA Outputs: These are a little bit of a holdover from the past but they can be used to connect to some mixing boards and some powered monitor systems.
- MIDI Outputs: MIDI outputs will allow you to send signal to any digital instrument or system that is capable of receiving MIDI input like a digital sound board.
Computer Connectivity Options
One of the things that always happens with technology is that it is always changing. This is true with audio technology as well. That being said, there are 4 different types of computer connections that are common with audio interfaces.
Thunderbolt has become the industry standard for all high performance interfaces. With its low latency and super high speeds, it blows away the competition. It is 8 times faster than USB 3 and will handle 40 Gbps. (Gigabytes per second) Normally you will only find Thunderbolt outputs on high end audio interfaces.
FireWire can be more reliable than USB. However it is not as commonly used and many audio interfaces do not come with a FireWire connection. Many PC’s do not come with a FireWire port so if you own a PC and want to use FireWire you may have to buy a FireWire card for your PC.
USB 2.0 and 3.0 is widely used in the industry. One of the reasons is that many audio interfaces will run on the USB power. This is especially helpful if you are doing mobile recording or using a laptop for your recording computer. Most audio interfaces come with a USB output.
PCI Express is a card that you can add to your desktop computer. It has the advantage of reducing latency and being able to handle a lot more data at once. This is the preferred method of interfacing audio with a computer in professional studios. However this can cost more than USB or FireWire. However there are PCIe cards on the market that are not too expensive for the home studio enthusiast.
Understanding Technical Specifications
If you are like me, when people start talking about things like bit depth and sample rate, my eyes start to gloss over. Does it really matter? Well in all honesty it does. But I will try to make it simple to understand.
Bit depth is simply the amount of decibel range the signal will have. 1 bit equals 6dB. Think of it this way. The less decibel range then the lower volume ranges or quieter part of your recording are more noisy and the louder sections will be less dynamic or impacting. A CD has a 96dB range. So you would need a 16 bit rate for that level of quality. Most professional studios use a 24 bit rate.
Sample rate is much more subjective. A sample is a digital copy of the signal at any given moment. A standard CD takes 44,100 samples of an audio signal per second. (44.1kHz) This sample rate is capable of reproducing any sound that the human ear can distinguish. However most audio professionals choose to work at 48kHz, 88.2kHz, 96kHz, or even 176.4kHz or 192kHz.
In the end remember that bit rate and sample rate are not as important as the quality of the converter changing the signal. It does no good to have a 24 bit rate signal if you have an inferior converter. That would be like putting a Nascar automobile engine in a go cart. It may be able to go 200mph but you wouldn’t want to be in it when it does.
Audio Interface Brands
At Taber’s Best Reviews we only recommend brands that have good reputations for customer service and quality of products. Here are the brands that we recommend you consider when purchasing your audio interface.
Putting It All Together
So what do you need? If you are a soloist, then you just need a basic system with a couple of line and mic inputs and a USB output. If you are a band or have a lot of different audio sources then you need more inputs and may need to consider a PCIe or Thunderbolt style computer connection. Whatever your need, I hope that this audio interface buyers guide has helped you define what you should look for.
Deciding To Purchase An Audio Interface
Now you have the information you need to purchase your audio interface. We would like to recommend that you take a look at our list of the best audio interfaces for home studios.