Ultimate Guide to the Best Budget Audio Interface
An audio interface is an electrical device that allows your computer and DAW to talk to your studio monitors, headphones, microphone, and other analog instruments. Unlike most mixers, they convert the zeros and ones of digital audio into an analog electrical waveform that your monitors can understand. They also work in reverse, meaning they turn an analog input signal into a digital audio signal. In this buying guide, we’ll go through the list of the best budget audio interfaces. You’ll also learn what to look for when shopping for an audio interface.
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Last Updated: 10/8/2021
In a Hurry? Here’s Our Top 3
9 of the Best Budget Audio Interfaces
M-Audio M-Track Duo
Behringer U-Phoria UM2
Focusrite Scarlett Solo (3rd Gen)
Audient iD4 MK II
PreSonus Studio 24c
Focusrite Scarlett 2i2 (3rd Gen)
Native Instruments Komplete Audio 2
Steinberg UR22 MKII
How to Pick the Best Budget Audio Interface
In the pro audio world, audio interfaces are used by producers, musicians, recordists, artists, and engineers to increase the sound quality of audio signals coming from and going to their DAW. Most PCs have their own internal interfaces and digital-to-analog converters, but for pro audio work, they just won’t cut it. And the reality is that the “best” budget audio interface will be slightly different for everyone, since we all have different needs as artists and musicians.
That being said, there are technical advantages that you will find across the board even in low-cost audio interfaces. In comparison to your computer’s stock DAC, audio interfaces allow for additional inputs and outputs (and the right kind, of inputs and outputs), adding to the flexibility and utility of your setup. Basically, if you’re interested in digital audio production, these are an absolute must-have item. Lets discuss the things you should look out for before you purchase the best budget audio interface out there.
During the conversion from analog to digital, for example when recording vocals through a microphone, the A/D converter in your audio interface performs a process called sampling. Sampling takes the continuous analog waveform from an instrument or mic and chops it into tiny discrete pieces of data many thousands of times per second. Each piece of data contains estimated information about the analog waveform amplitude at the time the sample was taken.
The sampling rate is the metric that tells us how many samples the audio interface can capture in 1 second. Higher sampling rates can capture higher frequencies and will convert analog audio to digital audio in greater detail. For a deeper understanding, take a look at the video below by iZotope.
Like they mentioned, some common sample rates are 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, and 192 kHz. The best budget audio interfaces will have a sampling rate of at least 44.1 kHz.
There is much debate on whether or not higher sampling rates actually make a difference. Some people argue that it actually causes signal distortion. There really is no consensus.
Either way, sampling at 44.1 kHz will allow us to fully handle all audio within the spectrum of human hearing due to the Nyquist Theorem – sample rate must be twice the maximum sampled frequency, in this case Fmax = 20 kHz since humans can’t hear anything beyond that.
Bit Depth for the Best Budget Audio Interface
Another important metric to look for when shopping for audio interfaces is bit depth. Bit depth is directly related to the dynamic range of the audio you’ll be able to process and also ties into the accuracy of the signal conversion.
When an analog signal is sampled, each sample gets assigned a point in time and an amplitude that consists of some combination of 0’s and 1’s that your computer can understand. The bit depth is what determines the accuracy of the digital signal’s amplitude when compared to the sampled analog signal.
16-bit quantization allows for 65,536 possible numerical values for the waveform amplitude, and 24-bit quantization allows for 16,777,216 possible values. More possible values means that the spacing of the amplitude grid that the samples get rounded to is tighter, which ultimately reduces quantization error. This is the error that occurs due to rounding the analog amplitude to the nearest bit.
Some will argue that 16-bit is enough, and it is for consumer audio. But for musicians and producers, 24-bit quantization is optimal. Not only is it much more accurate, but it also allows for a higher dynamic range (96 dB for 16-bit to 144 dB for 24-bit). This ultimately allows for more headroom in your mix and makes mistakes in gain settings less of a problem. For this reason, we should shoot for at least a 24-bit bit depth capability in our audio interface.
Latency & Buffer Size
The digital-to-analog converter (DAC) and analog-to-digital converter (ADC) in your audio interface are the microprocessors that do the actual signal conversion. These play a big role in the quality and price of your audio interface.
The latency, or the time it takes for the signal to be processed by the audio interface, will depend on your A/D and D/A converters, drivers, and buffer settings. It also depends to some degree on your digital I/O interface – meaning the type of hardware your computer uses to connect to your audio interface.
Some common choices are USB 2.0, USB 3.0, FireWire, Thunderbolt, and PCI or PCIe. USB is the slowest but also the cheapest and most common. Thunderbolt 3 is about 8 times faster then USB 3.0 The latency time is usually expressed in milliseconds, and the lower latency is better, especially for recording.
This spec tells us what the loudest and quietest signals that the interface is capable of handling are. Dynamic range is the difference between the quietest and loudest parts of an audio signal, usually expressed in A-weighted dB. A-weighting puts more emphasis on parts of the spectrum that the human ear is most sensitive to. It’s important to consider whether or not the specification is A-weighted, since A-weighting adds significantly to the dynamic range.
120 dBA or higher with 24-bit resolution is generally considered a very good dynamic range specification for an audio interface. These numbers were unheard of for an affordable audio interface years ago, but modern technology has caught up and you can now find these figures in the budget home studio category. The bottom line is, the higher the dynamic range the better. This means our audio interface will be more capable when recording a variety of sounds.
Total Harmonic Distortion & Noise
Another spec to look out for is THD+N, which stands for “total harmonic distortion plus noise.” This is measured by feeding a pure sine wave at a given level and frequency, usually 0 dBFS at 1 kHz, into the interface. Then we analyze what comes out. The difference in input and output levels is the THD+N figure in dB. Harmonics and noise are unwanted audio artifacts introduced to the signal by the internal circuitry of the audio interface, so the lower the THD+N, the better. It’s expressed as a negative number. -110 dB of THD+N is a very low value for an audio interface. Commonly, you’ll see it expressed as a percentage. This is just the noise and distortion level as a percentage of the overall input signal level.
Phantom power is DC electrical power used to polarize the capsules of professional-grade condenser mics. The best budget audio interface for someone who needs to do recording work will have phantom power circuitry and switches built into the device. Usually, if the audio interface has an input dedicated specifically to microphone use (an XLR input), then it will also include phantom power. Audio interfaces with phantom power on board will remove the need for additional gear, which takes up your precious desk space and money, too.
Balanced Input/Output Connections for the Best Budget Audio Interface
Ideally, the best budget audio interfaces will have audio I/O connection types that utilize signal balancing. Balancing is a way to eliminate radio frequency noise that gets introduced to the audio signal from the surrounding environment. For pro audio applications, we’re looking mainly for balanced 3-pin XLR cable sockets and 1/4″ TRS jacks.
Some audio interfaces only have accommodations for unbalanced S/PDIF, RCA, and TS inputs and outputs, which is not recommended for anything that you want to sound professional. However, you will still see some interfaces in the list below that lack balanced outputs. When it comes to features, balancing seems to be the first to get the axe in order to cut costs. The main takeaway here is that balanced I/O will ultimately result in a cleaner audio signal.
On the subject of I/O, it’s important to also think about how many inputs and outputs you’ll need. This is going to be different for everyone and there is no “best” number, just a number that will best suit your own needs. Additional I/O requirements will increase the amount of money you’re going to need to spend, and very well may push you out of the budget/entry-level range in terms of price. If you want to record your five-man band during a live session, you’ll need more. If you want to record a single vocalist and nothing more, maybe a single XLR input will do.
Line Level vs. Instrument Level vs. Mic Level Signals
It’s important to differentiate between the different signal voltage levels you’ll encounter and then determine if the audio interface you choose can handle what you need it to. Typically, mic level signals are the lowest and require amplification by a preamp to bring up to line level, which is the signal voltage level being fed into your monitors. Instrument level signals are found somewhere in between line level and mic level.
Some audio interfaces have switches that can change their preamp output between different signal levels. The more features the better, but it can add to the price. If it ends up costing more, get only what you need for the job at hand.
Best Budget Audio Interface Recap & Other Buying Considerations
Here are the common things to look for in your search for the best budget audio interface for you:
- Sample rate should be at least 44.1 kHz
- Low latency: below 1 ms round trip is considered very fast
- Bit depth at 24 bit or higher will allow for a higher dynamic range and higher signal-to-noise ratio (SNR)
- Low THD+N: -110 dB is an excellent THD+N rating for an audio interface
- High dynamic range: above 120 dBA is great
- Look for balanced XLR or 1/4″ TRS inputs and outputs – add to price, but worth it!
- Look for +48 V phantom power switch if you’ll be using a condenser mic for recording
Let’s look at some of the questions you should be asking yourself when shopping for the best budget audio interface:
- We touched on this earlier, but what type of inputs and outputs, and how many of each, will you need for what you want to do?
- Does it need to have a headphone jack? Will you be mixing or recording with headphones? How many?
- What mix of audio quality and utility will you need to balance in your decision? For example, let’s say you need 8 inputs. You may have to sacrifice higher sampling rate settings to remain within budget.
- What type of digital I/O will you need? USB is the slowest, but also the most budget-friendly. Others include FireWire, PCIe, and Thunderbolt connections.
Best Budget Audio Interface: Concluding Remarks
Ultimately, your decision here should be based off the specific use and application for your audio interface. You’ll need to determine how many inputs and outputs you’ll need, what type of OS, DAW, and digital interface compatibility you’ll need, and how much you can afford, and then choose an audio interface that will best satisfy those needs.
There are a few on the above list that are cheaper than most budget audio interfaces, but lack some essentials. In an ideal world, everyone would be able to afford the minimum needed to produce and edit digital audio and achieve a professional sound, but that’s not always possible. If you can, try to make sure your budget audio interface has the following:
- Balanced XLR or quarter inch TRS cable inputs and outputs
- Bit depth/resolution of at least 24-bits
- Sample rate of at least 44.1 kHz
- As low-latency as possible
Thanks for reading, and I hope this helps you make a great choice for your budget audio interface purchase!