This roundup is focused on finding an audio interface with 4 inputs, which can get a little bit technical, so we'll cover some of the basics.
On an audio interface an input is a jack, usually TRS or XLR, that allows you to plug in either an instrument or a microphone. Many input jacks on USB devices are setup to accept either an instrument cable (TRS) or a microphone cable (XLR).
We simply call that a "combo."
In your case, you're looking for four of these inputs, though it's important to read the fine print on exactly what kind of inputs you're getting.
For example, you might have two for instruments and two for microphones, or four for microphones or four for instruments.
It just depends on the device in question.
How to Identify an Audio Interface with 4 Inputs
Identifying these can be confusing, so let's go through another example. This Behringer interface clearly has four inputs on the front panel that are an XLR/TRS combo which, again, means they have both a mic and line input:
These inputs are usually - but not always - on the front of the interface. Some are split up with two on the front and two on the back.
On rare occasions, we've seen manufacturers count a single combo input as two inputs - giving you one XLR and one TRS in the same spot. The only problem is that you can only use one of these at a time.
However, we've avoided listing any interfaces that label their specs that way.
All the interfaces in this list allow you four simultaneous connections.
Audio Interface with 4 Inputs (full list)
We've vetted all the audio interfaces in this list and verified that they each have four separate inputs. There are a variety of connections, including USB, Thunderbolt, and MIDI, but we've made certain that the primary feature of having four inputs is present in each device.
Keep in mind, this is not a ranking or necessarily a recommendation list, but we've focused on top-selling options from reputable brands, and believe it's a "safe" list to buy from.
If you have questions, feel free to drop those in the comments section below.
- Behringer U-Phoria UMC404HD USB Audio Interface: 4 x combo
- Universal Audio Apollo x4 Heritage Edition 12x18 Thunderbolt 3 Audio Interface: 2 x TRS only and 4 x combo
- Focusrite Scarlett 18i8 3rd Gen USB Audio Interface: 4 x combo and 4 TRS only
- Zoom PodTrak P4 4-input Ultimate Recorder for Podcasting: 4 x XLR only
- iConnectivity AUDIO4c Dual USB-C Audio and MIDI Interface: 4 x combo
- Steinberg UR-RT4 USB Audio Interface with 4 Rupert Neve Transformers: 4 x combo and 2 x TRS only
- Audient EVO 8 USB Audio Interface: 4 x combo and 1 TRS only
- TASCAM US-4x4HR USB Audio Interface: 4 XLR only and 4 TRS only
- TASCAM Series 208i USB Audio / MIDI Interface: 4 x combo
- Roland Rubix 44 USB Audio Interface: 4 x combo
- MOTU MicroBook IIc Mobile USB iOS Audio Interface: 1 x XLR only and 3 TRS only
- ART USB IV 4x4 USB Audio Interface: 4 x combo
How many inputs do I need?
The number of inputs in an audio interface can vary pretty widely. High-end interfaces will house 32 or even 64 inputs, while the smaller units can go as low as one or two inputs.
For your situation, it's important to think of the inputs you need in terms of mixer channels.
How many channels would you need to perform what you want to record or stream to a computer?
A good rule of thumb is to not only cover the number of simultaneous channels you want to record, but also have a couple extra available. With four inputs, that means you could theoretically record four separate microphones or instruments at the same time.
For most small bands and/or home recording studios, that should be enough.
How many outputs do I need?
Audio interfaces can have their own outputs that are in addition to the output being sent through the USB or Thunderbolt connection. The most common type of output would be stereo TRS outputs for studio monitors, which is usually labeled as a main left and right jack.
You don't need a lot of outputs unless you're trying to feed more than two studio monitors, which most small recording setups don't require.
A headphone out - often on the front of an audio interface - is also good to have.
Should I go with USB or Thunderbolt?
Thunderbolt connections are faster than USB and often preferred by Mac users, but we've had good experiences using/testing both types of interfaces. Thunderbolt connections are typically more expensive, so we rounded up a list of the best options here:
Read more: Best Thunderbolt audio interface
What is the best option from this list?
Of this list, we're partial to the Audient EVO, the Focusrite Scarlett, and the Universal Audio Apollo series. Any of those three are going to be fairly solid options, though with some significant variation their pricing.
All these interfaces get you to four inputs with either TRS or XLR jacks, or a combination of both. Again, we've avoided interfaces that call two combo jacks (with an XLR and TRS each) as four inputs, because you can only use one at a time.
In some form, all these units will allow you to run four channels or four input devices (either instruments or microphones) at one time.
Hopefully you've found this list helpful as you search out the ideal audio interface.
Questions and Adding an Audio Interface with 4 Inputs
Do you have questions about the audio interfaces we've listed?
If so, feel free to drop them in the comments section below and we'll help out as much as possible.
That's also a good place to recommend additions to this list. Remember, they need to have four inputs, but if you recommend something we can use, we'll update the list and give you credit at the top of this page.
We'll see you there.