Best 4 Input Audio Interface [2022 Reviewed]

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All text and image links lead to Amazon unless stated otherwise. All product scores are based on ProRec’s in-house scoring model

Thumbnail4 Input Audio InterfacesProRec ScorePrice
UA Volt 476UA Volt 476
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Focusrite Scarlett 4i4 3rd GenFocusrite Scarlett 4i4 3rd Gen
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If you’re looking to upgrade your audio interface, or if you’re just starting out with your production journey and need a reliable interface, then a crucial question that always comes up is how many inputs do you actually need? The answer to that question really depends on your use case, what it is you are trying to do, and whether you’re running a more professional studio or if you’re just looking to get something for recording at home.

In general, it’s always a good idea to go for extra inputs. Having a single or dual input interface can work if you’re a guitar player and want to hook up a mic along with an instrument. However, if your use case is anything beyond that then having fewer inputs will always have you wishing that you had more so you do not have to keep doing multiple passes or keep swapping cords on different gear whenever you record.

When choosing a 4 input audio interface, or an interface regardless of the I/O configuration, your first selection criteria should always be the sound quality. Good preamps and pleasant transients along with a crystal clear sound is what differentiates interfaces. You also want something that has good build quality so it lasts you for a while and you get your money’s worth before you inevitably choose to upgrade.

Four inputs on an interface is actually a pretty decent number. Having four XLR/Line combos would truly be magical but something with two combos and two lines would be pretty decent and also budget friendly at the same time. One thing to note is that if you are looking to connect a condenser mic, you always want at least one of your inputs to have Phantom power, ideally +48v.

MIDI I/O is great but not always a requirement, it really depends on your use case. You want something that is easy to use, easy to setup and what will stand the test of time. There are a lot of interfaces in the market but not all of them are created equal. For modern interfaces, having good drivers is an essential selection criteria, some would even argue as it being the most important. There are also other advanced features such as on board DSPs, ADAT and SPDIF expansion which are found on more expensive interfaces.

Finally, you want to make sure that the interface you purchase hooks up to your computer. Most modern interfaces feature USB and Thunderbolt ports. While there are benefits to each, from our testing we have noticed that when interfaces are built well, having one type of port vs. the other has no significant impact on latency. You should focus more on the sound quality and other aspects and get an interface that hooks up to your machine with whatever connectivity options you have available.

Best Audio Interfaces with 4 Inputs Reviews

All text and image links lead to Amazon unless stated otherwise. All product scores are based on ProRec’s in-house scoring model

UA Volt 476
8.9/10ProRec Score
8.9average Score
ProRec Score – UA Volt 476
Price to Performance
Sound Quality
Additional Features

The UA Volt 476 is a 4X4 mid-level USB audio interface that features a 192kHz sample rate and a 24 bit depth. It has a very pleasant vintage design with a modern twist. The 476 features 2 XLR/TRS combo type inputs each with its own INST button (used for high impedance inputs), a shared phantom power toggle,  a ¼’’ headphone jack with its own volume encoder and 2 line inputs.

It also features 4 line outputs on its rear panel and 2 monitoring sockets. On the same panel, you’ll find a MIDI I/O, a USB-C socket, a 5V external power jack, and a power switch.

The main panel of the 476 contains most of its controls. It features 2 gain knobs for your 2 separate XLR/TRS combo inputs along with “vintage” and “76 compressor” toggles. The vintage button activates the unit’s built-in 610 preamps which are great if you want to add some warmth to your recordings. The “76 compressor” feature is based on UA’s classic 1176 compressor which is also built into the device.

There is also a large monitor control knob that allows you to control your source’s levels. You can indicate this source by toggling any of the 4 well-labeled monitor source buttons. The Volt 476 also has a bunch of 5-level LED meters on its top right corner that allow you to gauge your inputs and outputs levels.

For its price range, the Volt 476 is an incredible unit! We only spent a couple of minutes setting it up before jumping into testing. Right off the bat, the Volt 476 produced great audio output without any tweaking. This is in part due to its crystal clear preamps which add almost zero noise. We then wanted to test out the “vintage” mode to see if it lives up to the hype. And it sure did! It added a very subtle yet pleasant warmth to our recordings and worked especially well with guitars. If you then pair it with the 76 compressor mode you get an unbeatable audio interface in terms of sound quality for this price

One thing we really appreciate about the Volt 476 is that it’s class-compliant. This means that you don’t have to install any mandatory drivers to operate it, it’s a plug-and-play type of device. We tested it with a Mac, Windows, iPad and even a LInux computer and it worked perfectly well with different device/OS combos. The unit’s knobs and buttons also have a great feel to them. Because of that, we really enjoyed the fine-tuning process. This may seem insignificant, but you’ll appreciate the small intricacies UA has integrated to create a user-friendly interface.

The volt series is UA’s attempt at grabbing a piece of the budget-friendly interfaces market. UA has had great success with their Apollo line of extremely powerful high-end interfaces. So, when UA announced the release of the Volt series, we had a clear idea of what was in store for us. The Volt 476 is the most expensive interface in this line. However, UA released the Volt 276 among other cheaper interfaces to target a broader range of users. The 276 is exactly similar to the 476 except that it features 2 less inputs and outputs. This does mean that the 276 is slightly cheaper, but even then the 476 seems like a better option considering that you get extra I/Os and a couple of extra features like the MONO toggle.

As much as the Volt 476 seems like a well-rounded unit, it does have some downsides. For example, while the unit’s preamps are incredibly clear and transparent, you don’t get a lot of gain to play with, especially with your line-inputs (channels 3 and 4). We had to use an external amplifier to get a good signal even with maxed gain settings. Also, you can’t route your inputs outside your DAW. So you might have to physically move your I/O which can be annoying if you frequently swap them. Additionally, the unit’s mono button seems to only collapse your channels 1 and 2 signals, but it doesn’t affect your monitoring output which would’ve been nice for mixing.

In all, the Volt 476 seems like it’s taking a stab at other budget-friendly audio interfaces in the market. And rightfully so. The unit is undoubtedly one of the most powerful interfaces in its price range. It’s inexpensive, well-designed, and offers a lot of commendable features. The effort UA has put into perfecting the Volt 476 becomes immediately evident right when you unbox the thing. So if you’re looking for a powerful yet affordable audio interface that’ll get you going for at least a few years, look no further.

UA Volt 476 Benefits

The Volt 476 features a built in 1176 compressor and a vintage mode for its preamps. These features really improve the sound quality and they integrate extremely well with each other.

It contains great preamps that provide you with extreme audio clarity and a lot of transparency.

The Volt 476 is class-compliant on all devices. You don’t have to go through the fuss of installing drivers to operate the thing. You can simply plug-and-play and it’ll work perfectly even on mobile and linux devices.

It has a very unique and pleasant design. You really won’t find any interface in the market that has a similar aesthetic.

You’ll really enjoy the fine-tuning process because of how nice the knobs and buttons feel.

UA Volt 476 Drawbacks

You don’t have a lot of gain to play around, and almost none on input channels 3 and 4. You might have to use an external amplifier if you want to get decent gain levels.

You don’t have an option to route your I/O except by physically moving them. This could be annoying for people who frequently swap I/O. However, it’s still manageable considering that you only have to deal with 4 I/O.

The MONO button seems to only combine signals from inputs 1 and 2. But, it doesn’t affect your monitoring outputs. However, it works great and gets the job done.

All text and image links lead to Amazon unless stated otherwise. All product scores are based on ProRec’s in-house scoring model

8.4/10ProRec Score
8.4average Score
ProRec Score – MOTU M4
Price to Performance
Sound Quality
Additional Features

The MOTU M4 is an extremely well-built USB audio interface that features 4 inputs and 4 outputs. It has a traditional tabletop form with a very slick black metallic body. On its rear panel, you’ll find 2 balanced line inputs, 4 balanced and 4 unbalanced line outputs, MIDI input/output sockets, and a USB-C input socket.

The front panel of the MOTU M4 is where the magic really happens. This panel features 2 TRS/XLR combo inputs, a full-color LCD display, and a bunch of control knobs and buttons. The largest knob is a monitor controller which sits next to a ¼’’ headphone output. This output also has its own volume encoder which enables you to control its output levels. The 2 separate inputs each have a 48V (phantom power) toggle, a MON button, and gain control knob. You can also find an input monitor mix knob which lets you choose the source of your audio (your direct inputs or your PC’s audio stream).

With regards to sound quality, the unit features a sampling rate of 192kHz and a 24 bit depth. This is in part due to its powerful D/A and A/D converters. These converters are none other than the ESS Sabre32 ultra which were exclusively featured in high-end audio interfaces. The M4 also contains great preamps that provide you with a 60dB of gain while also being incredibly transparent and noise free.

When we finally had a go at the M4, the first thing we noticed was the LCD display. MOTU’s audio interfaces have always been renowned for their incredibly accurate metering screens. However, up until the release of the M series, MOTU has only ever created high-end interfaces. We were curious to see how an LCD on a cheaper model would compare to those of the more high end interfaces in the past. After using the interface for a while, it turned out that this display is extremely precise and accurate. That is a unique feature, since you won’t find an audio interface in this price range that offers similar metering capabilities.

We then started benchmarking the M4 against other similar interfaces. We can confidently say that the sound quality of the M4 is also one of the best in its price range. The preamps are exceptionally quiet and clean. We tried to limit-test it by maxing out the gain and it still managed to produce transparent audio with very little noise. The latency on this thing is also unprecedented for an interface of such price. With the latest USB-driver, the M4 was able to provide us with less than 2ms of round trip latency! The M4 also features loopback connectivity which enables you to combine audio from your PC’s audio stream and your device’s inputs. This is also an uncommon feature in such budget-level interfaces.

Since the M-series is MOTU’s first attempt at creating budget interfaces, there aren’t really any comparable predecessors. Yet, the M-series includes both the M4 and the M2 which is a slightly cheaper version with less features. The difference between the M2 and the M4 is mainly in the number of inputs. As the name suggests, the M2 is a 2×2 interface which means that it has 2 less inputs and outputs compared to the M4. These different I/Os are of line type. The M2 also doesn’t feature a playback monitor mix knob like the M4 does. Other than that, we couldn’t find any noticeable differences in performance between both units. So, it’s really a matter of  choosing whether you want to pay slightly more for 2 more extra I/Os.

The MOTU M4 does have a few drawbacks. For example, while the M4’s relatively compact and tabletop form makes it perfect for on-the-go purposes, you might find that the control buttons and gain knobs are somewhat irritating to use because of how small they are.While the metering display of the M4 is highly accurate, it does seem somewhat slow and has a slight delay before updating in real-time. However, it is more of a peripheral component and it still does a great job anyways. Some people also reported driver issues with the M4. However, we didn’t run into such issues neither on Mac nor on Windows. Plus, such problems are bound to occur with any USB interface. Even then, the rate of people reporting such issues is very low compared to other interfaces.

Overall, the MOTU M4 is a pretty powerful unit that excels at its price range. With more than 40 years of experience, MOTU have really outdone themselves with their M-series line of cost-efficient interfaces. What the MOTU M4 offers is definitely worth every buck you put to it. We really recommend the M4 as a solid purchase that you cant go wrong with.

MOTU M4 Benefits

The M4 contains the ESS SABRE32 Ultra DAC which is an extremely powerful converter that is used in high-end interfaces.

The M4 has a very slick metallic design. Its comparatively compact tabletop form also makes it perfect for portability purposes.

The unit contains extremely transparent preamps that provide you with a 60 dB of range.

It features a full-color LCD screen that is extremely accurate. This makes it perfect for gauging your I/Os levels.

It boasts one of the lowest latencies for a budget interface. You get a whopping 2ms or less of round trip latency.

MOTU M4 Drawbacks

The knobs and buttons of the M4 are really small. This might be irritating especially to people who frequently use these controls.

You might notice a slight delay on the LCD display. However, the LCD is an additional feature that is part of MOTU’s branding. Plus, it does a great job at accurately indicating your I/O levels even if with this slight delay.

Some people have reported driver issues with the M4. However, we really didn’t run into any issues of such sorts. Plus, the frequency of these reports are really low compared to other interfaces that actually suffer from such issues.

All text and image links lead to Amazon unless stated otherwise. All product scores are based on ProRec’s in-house scoring model

Focusrite Scarlett 4i4 3rd Gen
7.9/10ProRec Score
7.9average Score
ProRec Score – Focusrite Scarlett 4i4
Price to Performance
Sound Quality
Additional Features

The Scarlett 4i4 is a bus powered USB-C audio interface that features 4 inputs and 4 outputs. It is a relatively compact and light interface which makes it perfect if you’re looking for something portable.

The 4i4 has a very simplistic design. Its front panel features 2 TRS/XLR combo inputs each with its own gain control. They also each have separate LEDs that indicate the state of the INST, PAD, and AIR features. You can also activate phantom power (48V) for input channels 1 and 2 through a common toggle. Other than that, there is a large monitor control knob which sits next to a ¼’’ headphone output that has its own output level knob. The unit’s rear panel features all 4 line outputs, 2 TRS line inputs, MIDI I/O sockets, and a USB-C input jack.

The Scarlett 4i4 can reach a maximum sample rate of 192kHz and a 24 bit depth. It contains 2 very powerful Scarlett microphone preamps along with the renowned AIR circuitry. If you haven’t used any Scarlett products, then we can best describe the AIR feature as a mid-high frequency booster that adds a unique pleasant effect to your recordings.

You can control most of your features and input gains through the Scarlett software. However, you can also use the physical gain controls if you are looking for some hands-on experience. These knobs feature an LED halo indicator which is extremely helpful for detecting clipping.

With regards to sound quality, the Scarlett 4i4 sounds incredibly crisp and pristine. When putting the 4i4 to the test, one thing that stands out is that Its preamps are hands down the best when it comes to affordable interfaces. They produce incredibly clear and granular audio while also creating almost zero noise. We also really appreciate the super-low latency on this thing. We can seamlessly monitor our mix in real-time even while running a bunch of plug-ins. The unit is also extremely easy to use. We would expect any user of any level to be able to use the 4i4 with no issues. Also, the halo indicators on the gain knobs are a much welcomed addition. It’s definitely a nice touch to steer away from the traditional level LED metering.

The 4i4 is a new addition with the 3rd gen Scarletts. As far as the 2nd gen is concerned, the closest interface to the 4i4 3rd gen is the 2i4 2nd gen, where the prominent difference is 2 inputs compared to the 4i4’s four inputs. In addition to the input configuration, the 4i4 also features MIDI I/O unlike the 2i4. Other differences include full control over inputs gain, phantom power, air mode, etc. on the 4i4 through the Scarlett software which isn’t something you could do on the 2i4. Instead, the 2i4 controls are entirely physical unlike the 4i4. In terms of sound quality, you’ll notice a very slight improvement in latency and audio output on the 4i4. Still, both units perform fairly close and the difference there is minimal.

The Scarlett 4i4 does have a few shortcomings. For example, while we could control some of the parameters such as input gain using the physical controls, most of the parameters are accessible exclusively through the Scarlett software. For instance, we can only control the gain on input channels 3-4 using the software which can be a bit irritating. There are reports online of people getting a random noise after owning the unit for a couple of weeks. We ran into a similar issue with a high-pitched noise while monitoring through headphones. However, unplugging/replugging the unit seemed to fix things for us, and we haven’t faced the same issue since then. In such a situation, it would’ve been nice if the 4i4 featured a power button to avoid having to manually plug/unplug the entire thing.

Overall, Scarlett products have never ceased to impress us nor their devoted fanbase. With the 4i4, you’re guaranteed a high quality, great sounding, and inexpensive interface that you can do almost anything with. It is extremely intuitive to use and has all the main features you would expect from a mid-level interface. We really recommend the Scarlett 4i4 especially if you are just starting out and want a powerful unit that can get you going for several years.

Focusrite Scarlett 4i4 Benefits

The 4i4 contains pristine preamps which provide excellent sound quality. These preamps are the best in the market in this price range.

The unit boasts an incredibly low latency. You can monitor your mix and run several plug-ins without any delay.

The Scarlett 4i4 features halo indicators on its gain knobs which are extremely helpful for detecting clipping.

You can control all your interface’s parameters through the Scarlett software.

It has a very intuitive and simple design. You can easily figure out how to operate it even if you’re just starting out.

Focusrite Scarlett 4i4 Drawbacks

You don’t have physical controls for a lot of your features like phantom power, INST, AIR, and channels’ 3-4 gain. Instead, you’ll have to use the Scarlett software to control these parameters and this takes away from the hands-on experience.

You might run into some noise issues after operating the unit for some time. For example, our unit started randomly producing noise on its headphone output. However, unplugging/replugging the unit seems to fix such issues for most users.

The unit doesn’t feature a power button, so you’ll have to manually unplug the interface if you want to power it off or vice versa. 


4 input audio interfaces comparison scoring model

According to the scoring model, all 3 audio interfaces scored fairly well with the lowest score being 7.9.  There isn’t a huge amount of variance (1) between the highest and lowest scoring products. The highest individual variances are in the price to performance, sound quality, and additional features categories. Unlike most of our comparisons where the competition usually ends up between 2 interfaces rather than all 3 (based on the closeness of their scores), the scoring here is pretty close which lead to an interesting comparison between all three interfaces at all levels.

Of the 3 units, the UA 476 provides you with the best sound quality and vastly outclasses the M4 and the 4i4 in terms of additional features. Its built-in compressor and vintage mode give it an edge over the other units in those two categories. Interestingly enough, you can see that all 3 units score exactly the same in the connectivity category. That is because all of them feature the same USB-C type connection. However, the only category in which the UA 476 scores the lowest is in the price-to-performance category. This is certainly expected since the UA 476 costs almost 50% more than the M4 and the 4i4. Yet, we are certain that it will provide you with a lot of value for your dollar.

However, we will point out that you get a bang for your buck with the MOTU M4! it is excellent in terms of sound quality and has a fair number of extra features at a very affordable price. If you are on a tight budget, then we would really recommend the M4 as a solid pick. On the other hand, the Scarlett 4i4 can be a slightly underwhelming purchase. That’s because the Motu M4 performs fairly better comparatively and costs almost exactly the same. So you might as well just go for the M4.

Overall, after a thorough analysis, we consider the UA 476 to be the best 4-input audio interface. It scores the highest (or tied for the lead) in all categories except for price to performance. It also has the best aesthetic we’ve ever seen on an interface with a great build quality. The built-in compressor and vintage preamps are also incredibly useful and uncommon for interfaces in this price range. With the 476, you’re guaranteed to get the best sound quality out of any interface in the mid-range price spectrum. UA has had a great run with their high-end Apollo interfaces, and their 476 seems to be taking a stab at the mid-range market. We genuinely appreciate the effort UA has put towards perfecting the 476. Every single aspect of it seems to mesh perfectly well. So, if you’re looking for an interface that’ll help you take the next step, then you should undeniably go for the 476!

Frequently Asked Questions

What are the benefits of getting an Audio Interface with 4 inputs vs. solo or 2 inputs?

Generally, having more inputs gives you a lot more flexibility in your recordings. If you’re a musician then you’ll probably use one input for your microphone and another for your instrument. In such cases, a 2-input interface can certainly get the job done. However, you might only need 2 inputs when you’re just starting out, but most artists will eventually want to expand their setup (e.g add a keyboard, synths, a 2nd mic, etc.). That’s why going for a 4 input interface will save you a lot in the long run since you won’t have to purchase a 2nd interface.

What can I do with an Audio Interface with 4 inputs?

You can do pretty much everything with a 4 inputs audio interface. Whether you want to record instruments, mics, or bass, a 4-inputs interface will let you record multiple sources at once. Additionally, most 4-inputs interfaces feature monitoring capabilities. So, you could listen to your multiple-input audio stream in real time. You get more control over all your inputs and you can record more than just a couple instruments at the same time.

Are there any limitations with an Audio Interface with 4 inputs? 

The only limitations that we can think of would be if you are wanting to record a live band or orchestra, and if you are wanting to record drums and you want each component of the drum to be mic’d separately. These are really two vastly different use cases that do not apply to most people when they are recording at home or in a studio. For live drums recording though, you would want an interface with more inputs (that is if you want to get more granular in your mix)

If I have the budget, should I go for an Audio Interface with more inputs?

This is totally your call. Do you see your use case evolving in the near future? If not, then you should be fine with a 4 input audio interface. However, if you do want to record drums or a live band at some point and if you think 4 inputs is not going to cover everything, then you may consider an interface with 6 inputs or more. Alternatively, you may also have other demands for a 6 to 8 input interface when recording live so getting both a 4 input interface and another interface with a higher input count may be a viable solution.