Best Rackmount Audio Interface [2022 Reviewed]

Introduction

Desktop based Audio Interfaces are awesome, but they will eventually clutter a studio. If you’re just running a small setup with a laptop and an interface then by all means a desktop interface is a good choice, however, if you have a bunch of extra modules (more than 10) then a rackmount interface is the way to go!

Rackmount audio interfaces are awesome because you can move them around and access a bunch of different settings/equipment through a patch bay. A lot of the rack interfaces are built clean and are super fast. They are made to be work horses and are geared towards professionals, not something a hobbyist musician typically uses.

When choosing a rackmount interface, you are mainly going after a more elaborate I/O configuration, as well as more premium features compared to a regular desktop audio interface. Rackmounts give your studio a more professional look and they also allow for more space. However, they’ll usually set you back a bit more than a regular desktop audio interface.

In most cases, rack mounts are available on high-end units. Because these units usually feature a lot of controls and I/Os, they’re often larger than your average desktop audio interface. That’s why manufacturers offer rack mounts to help minimize any clutter that results from having multiple I/O channels.

When selecting a rackmount audio interface, you should focus on its sound quality as much as you would on its number of I/O channels. High fidelity converters and preamps are what you should aim for. Because of the competitive state of the market, you’ll find a lot of rack mount interfaces that offer superb sound quality for relatively inexpensive prices. However, just make sure that you’re not overpaying for any extra features that you might not need.

Additionally, latency can be a very important selection criteria when choosing a rackmount audio interface. With several I/O channels, you’re bound to run into some latency during your recording sessions. That’s why you should pick an interface that offers TB3 connectivity or at least a USB connection for good performance. If you’re also planning on running several plugins, then you might need to look for a unit that features an onboard DSP.

To sum it up, your main criteria when choosing a rackmount audio interface should be its sound quality and number of I/O channels. You should also factor in the price of the unit as to not pay for something too extravagant with excessive features. Generally, you should go for a unit with silent preamps, accurate converters, and low latency while also ensuring that the interface has enough I/O channels to accommodate all your needs.

Best Rackmount Audio Interface Reviews

Universal Audio Apollo x8p Heritage Edition

9.2Average Score
Universal Audio Apollo x8p Heritage Edition
Price to Performance
7.5
Input/Output
8.5
Sound Quality
10
Connectivity
10
Additional features
10

The Universal Audio Apollo x8p Heritage Edition is a professional grade TB3 audio interface. It features 18 inputs and 22 outputs all of which are packed into a large metallic body. It also comes with a detachable rack mount which is useful for space management.

The backside of the x8p features all of its sockets. On this panel, you’ll find 8 XLR/TRS mic inputs, 2 monitor outputs, and 8 line inputs/8 line outputs which are accessible through Sub-D25. You’ll also find a world clock, dual ADAT I/O sockets, 2 TB3 ports, a 12V DC power socket, and a 75 Ω button.

On the front panel, you’ll find 2 Hi-Z sockets for high impedance inputs, 2 headphone outputs with their separate volume controllers, a preamp gain controller, a monitor knob, and a power switch. There are also a set of buttons with different functions like 48V, Cut, Pad, link, alt, meter and an input button that denotes which input is being affected by the preamp knob. These buttons surround a large colored LED display which provides a fairly detailed metering of the inputs and the different active functions.

The Apollo x8p is loaded with incredibly powerful components. From UA’s proprietary Unison preamps to its elite-class converters, the Apollo x8p has reached the pinnacle when it comes to sound quality. We started testing the x8p by hooking up a Shure mv7 to one of its XLR inputs. As we expected, the X8p was producing impeccable audio.

The converters are one of the best in the market with 129 dB dynamic range and -119 dB of THD+N which directly translates to artifact free recordings. We even ran the x8p with the lowest buffer settings, highest sample rate of 192kHz while using multiple plugins and it faired really well. There were no hiccups in terms of performance at all.

As for the preamps, the X8p is equipped with 8 awfully powerful Unison preamps which are capable of emulating renowned preamps such as Manley, Neve, Helios, etc. We’ve used a Neve 1073 before so we can attest that the X8P does an incredible job mimicking the Neve sounds. It even alters its own circuitry to match the emulated preamps’ gain sweet spots and input impedances.

However, it’s not like we needed to use any emulations. On the contrary, the default preamps settings already provided us with incredibly transparent audio and a ton of head room. We didn’t face any drops, clipping, or any sort of distortion even at high gain levels. The built-in preamps on this interface are as good as most high-end external standalone preamps

As great as the x8p is, there are a couple of downsides we should point out. For example, to get the x8p working, in most instances you will have to install a firmware update. While we had no issues installing the mac firmware update, but we can’t say the same about Windows devices. It was tough to get the x8p working on our PC, we were never presented with a firmware update option. We had to reboot and plug/unplug the interface a few times before the update option showed up. Not sure why it worked out this way, but it is something to keep in mind if you are a Windows user. We did google a little bit and there were a few other ways to go around it, if you get the x8p then you will have to do some research to get the firmware update working on Windows.

Additionally, we reckon that UA should have made its plugins more manageable. All of the UAD plugins will appear in your DAW regardless of whether you purchased them or not. This means that sifting through them can be a bit annoying and time consuming, It would’ve been useful if UA implemented a feature that allowed us to filter plugins depending on ownership.

The difference between the Apollo x8p and the Apollo x8 which is a slightly cheaper version of the x8p mainly lies in the number of mic I/Os. As we mentioned, the x8p features 8 mic inputs feeding into 8 Unison preamps. On the other hand, the x8 only features 4 mic ins which are also limited to XLR type inputs. However, the x8 features 2 extra outputs and an extra SPDIF I/O socket. It also features TRS sockets for its Inputs and outputs instead of the D-25 connector which can be found on the X8p. Otherwise, both units have the exact same components and features.

Overall, the x8p is one of the best audio interfaces in the market. With pristine sound quality, a ton of additional features and incredibly low latency (due to its 6 built-in Sharc chips and TB3 technology) UA has built something really worthwhile. If you’re in the market for the best rack mountable audio interface, then the Apollo x8p is one that you shouldn’t ignore.

Apollo x8p Benefits

It features ultra-low latency due to its 6 built-in DSP.

You get one of the best sounding units in the market.

The x8p has a wide selection of UA plugins.

It has a ton of extra features and a lot of functionality buttons.

It contains 8 Unison preamps which can emulate a lot of the renowned preamps.

Apollo x8p Drawbacks

You’ll have to install a firmware update which is hard to implement on Windows devices.

The UAD plugins can be a bit hard to manage.

It is relatively expensive

Antelope Audio Discrete 8 Pro Synergy Core

9.3Average Score
Antelope Audio Discrete 8 Pro Synergy Core
Price to Performance
8.5
Input/Output
10
Sound Quality
9
Connectivity
10
Additional features
9

The Antelope Audio Discrete 8 Pro Synergy Core is one of the most powerful rack mountable audio interfaces that features both a USB and a TB3 connection. It can power up to 26 inputs and 32 outputs, most of which can be accessed through its SPDIF/ADAT connections.

The back panel of the 8 pro synergy core features 6 TRS/XLR combo mic inputs, 2 monitors outputs, 2 re-amp sockets, and 8 line-outputs which are accessible through the D-25 socket. It also has 2 ADAT I/O sockets, an SPDIF I/O socket, a foot switch (for foot pedals), 3 world clock outputs, and 1 word clock input. Other than that, you’ll find an 18V power socket and dual USB ports.

The front panel of the 8 pro is what gives the unit its stylish looks. Here you’ll find an extra 2 XLR/TRS mic inputs which are mainly tailored for instruments along with 2 headphone outputs that have their own volume encoders. This panel also contains 8 gain knobs for the 8 individual XLR inputs which can be tracked through the colored LCD metering display. Finally, there is a large rotary dial that sits next to 3 function buttons that can be used to cycle through your device status and features.

In terms of build quality, the Discrete 8 pro is a very durable and a rather hefty unit. In spite of the elaborate I/O configuration, the unit still maintains a very slick design. We like how the controls feel, especially the metallic knobs which are very smooth and click when rotated.

In terms of sound quality, the 8 pro is equipped with the finest converters and preamps in the market. The transistor preamps (total 6) provide 65 dB of gain range and a very low noise floor. This means that the 8 pro can enhance the audio quality of any type of mic whether it be gain hungry dynamic mics or sensitive condenser mics. We tried maxing out the gain levels on our Lewitt LCT 940 condenser mic and the 8 pro kept on producing extremely transparent and noise-free audio throughout! Exactly what you should expect from an interface like this one.

As for its converters, the 8 pro contains world class ADCs and DACs which provide a -121 dB and -122 dB dynamic range (A-weighted) respectively. It also features Antelope’s proprietary 64-bit AFC clocking technology which nulls out any sort of jitter/latency. Putting the converters to test, we were happy with the sheer amount of detail they were able to retain. The audio output sounds very crisp and incredibly detailed with a much wider soundstage.

Additionally, the 8 pro comes with 37 built-in plugins which can be extremely useful. We experimented with different dynamic processors and some guitar amps, and they sounded pretty cool. As for the latency, it is practically nonexistent, even when running multiple plugins. This is mainly because of the ybrid system of 2 built in DSP cores and FPGA.

However, while we did have an overall pleasant experience with the 8 pro, there were a couple of drawbacks that could use some tweaking. For instance, the unit’s full routing matrix is extremely confusing to use especially if you’re not experienced. The same also goes for the software which isn’t very user-friendly and can be a bit hard to navigate. Moreover, you won’t find a MIDI I/O socket on the 8 pro, but you can still hook up a MIDI interface through ADAT which worked perfectly fine for us. Otherwise, we have no qualms about the unit’s audio quality nor did we run into any sort of driver issues.

Compared to the discrete 8 which came before the 8 pro, the 8 pro underwent some decent upgrades. In terms of sound quality, the 8 pro is equipped with slightly better converters even though both units have the same preamps. The 8 pro also features 2 extra outputs along with TB3 connectivity compared to the TB2 on the original discrete 8. Additionally, the 8 pro has extra DSP and features a much more elaborate routing matrix than the discrete 8 which had limited routing capabilities. While everything else remains relatively similar, the discrete 8 pro costs fairly more than the original discrete 8 which was released only 1 year prior.

Overall, the Antelope Discrete 8 pro is a robust audio interface that produces impeccable audio. Everything from its amazing build quality to its incredibly low latency makes it one of the best audio interfaces in the market. We recommend the 8 pro if you want a powerful rackmount audio interface that will help take your production skills to the next level.

Discrete 8 Pro Benefits

The Discrete 8 pro has one of best preamps and converters in the market.

You get access to 37 built in plugins.

It features 64-bit AFC clocking technology which translates to zero jitter/latency.

The unit has amazing build quality.

The 8 pro has 2 built-in DSP and an FPGA.

Discrete 8 Pro Drawbacks

The software and the routing matrix can be a bit confusing.

You won’t find a MIDI I/O socket.

Focusrite Scarlett 18i20 3rd Gen

7.2Average Score
Universal Audio Apollo x8p Heritage Edition
Price to Performance
9.5
Input/Output
8
Sound Quality
6.5
Connectivity
5
Additional features
7

The Focusrite Scarlett 18i20 3rd gen is an affordable rackmount USB 2.0 audio interface that contains 18 ins and 20 outs. It is fully enclosed in durable metal which constitutes most of its weight. The unit features a total of 8 XLR/TRS mic inputs: 6 on its back panel, and 2 on its front panel. The latter also has a 5 level LED gain meter for these mic inputs along with their corresponding gain knobs.

Each of the mic inputs has a PAD toggle and an AIR indicator (activatable through software) except channels 1 and 2 which also feature an INST button (used for high impedance inputs). Other than that you’ll find 2 volume encoders for the 2 headphone outputs, a monitor knob, a set of function buttons, and a power switch on the front side.

On the back panel you’ll find 10 TRS line outputs, 6 mic inputs, a world clock output, a MIDI I/O, a 100-220V AC power socket, and the USB-C port. The panel also features DUAL Adat I/O sockets and an SPDIF I/O.

With regards to sound quality, we’ve had a fairly pleasant experience with the 18i20. It is equipped with great converters that provide 111 dB of dynamic range (A-weighted) on its mic inputs. While they aren’t the most extravagant, they’re still remarkable considering the 18i20’s price tag. Plus, when we tested them, they were reliably capturing the room with immaculate detail and without adding any color.

As for its mic pres, the 18i20 contains 8 of Focusrite’s renowned preamps which are very transparent and offer a lot of gain. To test them out, we started to gradually increase the gain until the audio started clipping (we were recording using a Shure SM57 dynamic mic). By doing so, we were able to reach very high gain levels and the audio remained pristine throughout. However, we should mention that when the audio did eventually clip, it became awfully distorted and unbearable to the ear. Disregarding that, we really think that the preamps are one of the best we’ve seen on a budget interface.

The AIR mode is one of Scarlett’s primary selling points. If you’re unaware, the AIR feature enhances your recording by boosting its mid to high frequencies. It works especially well with instruments and vocals (specifically with mics that have a flat response curve). We’ve been using the AIR mode for practically everything (except for drums) because of the subtle but pleasant effect it has. It is a built-in emulator as well, so it doesn’t really affect latency.

Compared to the 18i20 2nd gen which was released around 3 years prior, the 18i20 3rd gen had some minor improvements in audio capability. While nothing extremely fancy, the 3rd gen offers slightly better gain range, THD+N, and dynamic range (2 dB difference at max). The 3rd gen does however offer extra function toggles and most importantly features the AIR mode which isn’t available on the 2nd gen. Other than that, we couldn’t find any major difference between both units as they even have the same build quality, design, and a relatively similar performance.

During our time with the unit, we encountered certain flaws that need to be addressed. For example, the Scarlett 18i20 would abruptly start producing random pops and clicks after some hours of operation. Occasionally, our headphone outputs would even bring about an unwanted static noise that persisted until we reset the device. Even though the Focusrite Control software that comes with the 18i20 is pretty easy to use, we would’ve preferred if the 18i20 didn’t rely on it so much. To use the 18i20, you have to be connected to a computer with active Control software at all times. Plus, a lot of the features can only be accessed through it which limits its standalone capability. However, everything else seems to work perfectly fine and the software installation process was very straightforward.

Overall, there is no other audio interface in the market that offers as many I/Os with similar audio capability in this price range. With 18 inputs and 20 outputs you’re getting a lot of value for your money. We recommend the Scarlett 18i20 if you are in the market for an inexpensive rackmount audio interface with clear preamps and extended features.

Scarlett 18i20 Benefits

The 18i20 contains powerful converters that can capture a lot of details with great precision.

Its preamps are one of the best in the budget audio interface market.

You get access to the AIR emulators which add a pleasant effect to your recordings.

The 18i20 is extremely price efficient.

It has great build quality and features a detachable rack mount which is very useful.

Scarlett 18i20 Drawbacks

You might get random clicks and pops with the 18i20 after operating it for a while.

You must connect your 18i20 to a Computer that has the Focusrite Control software to use it.

The Physical controls are limited, most of the features can only be accessed through the Control software.

Verdict

According to our scoring model, you’ll notice a huge amount of variance (2) between the highest and lowest scoring units. If you analyze the graphs further, you’ll find that the highest variances are in the Connectivity, Sound quality, and Input/Output categories. While both the X8p and the Discrete 8 Pro score fairly similar in all these categories,  the Scarlett 18i20 falls behind in every single one of them. Essentially, this huge score gap can be attributed to the Scarlett 18i20.

On the other hand, you can see that the Discrete 8 pro performs incredibly well throughout scoring at least 8.5 in any given category. Not only does it have a very high score baseline but it also excels in the Input/Output and Connectivity categories. As we mentioned, the 8 pro features Dual connectivity options which include both TB3 and USB-B sockets. It also features 26 inputs and 32 outputs which are more than enough for any given purpose. Nevertheless, you’ll find that the Discrete 8 pro scores the lowest in the Price to performance category out of the 5 categories. However, it is still relatively extremely price efficient.

Albeit, we should note that the Apollo X8p is on par with the DIscrete 8 pro in almost every aspect. You can see that the overall score difference between both units is only 0.1 which is negligible. While the X8p does cost quite a bit more than the 8 pro, the X8p offers superior sound quality and more features. So it’s really a matter of choosing what features/categories you value more. However, if you were to look at the 18i20 which has an overall score of 7.2, you’ll see that it only drags down the competition. Even so, it can still be a decent choice if you are on a tight budget as it costs a mere fraction of the price of the other units.

Nonetheless, our scoring model concludes  the Antelope Discrete 8 pro as the best rackmount audio interface of the bunch leading with an overall score of 9.3. With its powerful converters, incredible preamps and remarkable number of I/Os the 8 pro has everything you would need from a pro level interface. It also contains a lot of additional features like built-in SX effects and AFC technology which really set it apart from its competition. We recommend the Discrete 8 Pro as a secure pruchase that you can’t regret.

Frequently Asked Questions

Why should I buy a Rackmount vs. Desktop audio interface?

Rackmount audio interfaces are easy to move around and are usually a lot faster than your usual desktop interfaces. They’re built to be used in professional studios and not something a hobbyist musician would be typically interested in. You get a lot more I/O in a Rackmount interface which is how they are always designed. Basically it’s a lot more interface in a rack than you would get in a standard desktop version. They’re excellent for when you want to hook up multiple instruments at the same time while recording in the studio. You also get additional features such as DSPs, headphone amps etc. that are less common on desktop interfaces.

Am I overpaying for a Rackmount Audio Interface?

They are always more expensive and that is because of the elaborate configuration. You are not overpaying, you’re actually getting good value for your money, at least with all the interfaces we have reviewed in this article. You should understand that manufacturers build Rackmount interfaces for their more expensive interface models. While they do cost more, the higher cost is justified for all the features that you get in return.

What is the most crucial aspect when buying a Rackmount Audio Interface?

It is not really any different than buying a desktop based audio interface. The only difference is design, the other aspects which include I/O configuration, sound quality (Preamps/converters), latency, and connectivity are all the same.

Will I need anything else for my Rackmount Audio Interface?

Not really, all of the equipment is pretty standard in terms of operation. However, to mount the interface you are going to need a rack, or you can buy a studio desk which comes with a rack shelf that has limited slots which will be sufficient for a single interface.