Universal Audio Buyers Guide 2022

Introduction to Apollo

Every Apollo interface comes with our Console application. Console eliminates the latency associated with DAW I/O buffering that makes monitoring problematic for the artist. By removing the DAW's "software input monitoring" feature from the monitoring signal flow altogether, the need to adjust I/O buffer sizes and latency is no longer an issue.

In addition, UAD Powered Plug-Ins can be inserted into all Console inputs and/or auxiliary returns (within available DSP resources), for the ultimate latency-free sonic experience while monitoring and/or tracking live performances. All processed (or unprocessed) mix buses, including the monitor, auxiliary, and cue buses, can be optionally routed into the DAW for recording. Using the Insert Effects Switch or the Individual Channel Effects Switches the operator can choose whether to print tracks with plug-ins or simply monitor through them and record to the DAW dry.

Apollo Family

Apollo features ALT (alternate) monitoring capabilities. ALT monitoring can be used to control alternate pair(s) of monitor speakers, which is convenient for quickly comparing how a mix sounds through a different set of speakers. Up to two pairs of ALT monitors can be used (one pair with Apollo Twin).

For quick recall of plug-ins for an entire channel, Channel Strip presets can be created with all settings for all plug-ins within the channel strip. These presets can then be loaded into any channel.

Up to four Apollo units of any model type (Apollo, Apollo 8, Apollo 8p, Apollo 16, Apollo 16 mkII, Apollo Twin) can be connected and used together as a single consolidated system. When multiple Apollo units are connected, all units are controlled within a single Console window, and the I/O complement of all devices are available within the DAW. Operating a multi-unit system is nearly identical to that of a single-unit system for seamless expansion when more I/O is needed. When multi-unit cascading, the number of Console inputs is increased to match the increased hardware inputs. When an Apollo Twin is used with any Apollo rackmount unit that is designated as master (monitor), it automatically becomes a remote control for control room monitor level and mute.

Which Apollo do I need?

With several Apollos to choose from, you are probably wondering which is the right one for you. It’s a question of input and output quantity/type and UAD-2 DSP power. A good insight into how many chips you might want for UAD-2 processing can be found on our UAD-2 Instance Chart. Remember that by utilizing our Expanded capabilities you can create an Apollo system by linking up to four Apollos together (one of which can be an Apollo Twin) for more ins and outs.

Apollo Twin Solo/Duo

Apollo Twin is our desktop solution and portable enough to easily take on the road or back and forth to rehearsals. Both the Apollo Twin Solo and Twin Duo feature the same Unison enabled mic preamps and UAD-2 Realtime (latency free) plug-in processing workflow that all of our rackmount Apollos use.

With two preamps and an ADAT/SPDIF optical input, the Apollo Twin Solo has enough inputs for the singer/songwriter or rapper and a single UAD-2 chip for plug-ins. Attaching your favorite multi-channel mic preamp via ADAT will give you ten mic preamps, enough to record a small band but with that many sources we recommend the Apollo Twin Duo with two UAD-2 processing chips. Beatmakers and EDM producers will appreciate Apollo Twin's UAD-2 plug-in processing and deciding between a Twin Solo or a Twin Duo will depend on how big your projects are. Guitar and bass players will revel in the Unison enabled DI and the extensive stomp box and amplifier plug-in choices available.

Apollo Twin MkII now has a built-in Talkback microphone. In Monitor Mode the six buttons under the display screen become active for studio communications and monitoring functions. The first button is Talkback: push to latch, hold for momentary. Talkback can feed any headphone amp or Cue Mix in an Apollo Extended system. If you don’t have an Expanded system you can still feed your local headphones or Cue Mixes. Using the Apollo Console, you can also instantiate plug-ins on the Talkback channel. This allows a compressor to reduce the dynamics of an excited producer, squeezing the control room to even out conversational level, or having some fun with effects in the Cue Mix to lighten the mood. Additionally, the Talkback microphone can be recorded on a separate track in your DAW. Use it to record banter in the control room, song notes about takes or instruments used, as a low fidelity crush microphone to blend in for creative sounds, or quick song ideas when inspiration strikes and your studio microphones are away in their boxes.

And remember that if you own an Apollo rack with Thunderbolt connection, Apollo Twin (Thunderbolt) becomes a remote volume and mute control. It also lets you conveniently plug in instruments and more microphones without having to go behind your rack and disturb your permanent wiring.

For those of you with Windows computers, Apollo Twin USB gives you the same power and sound as Twin Duo but using a USB 3.0 Superspeed connector.

Apollo 8 Duo and Quad

Apollo 8 Duo and Quad are the choice for home and professional studios that need power and flexibility. Each has four Unison enabled mic preamps, two Unison Dis, four line level ins and outs, ADAT in and out, and coaxial SPDIF in and out. Top it off with Wordclock I/O for sync and you have enough connectivity for most professional applications. Choose between a Duo or a Quad depending on your UAD-2 DSP needs.

Apollo 8p

When four preamps are not enough for drum kits and the like, Apollo 8p brings eight Unison enabled mic preamps and two DIs to the session. It also features six line level outs, ADAT in and out, and Wordclock in and out. Since we assume you need it, Apollo 8p is only available as a Quad DSP.

Apollo 16

If your forte is mixing and don’t have tracking needs, or you already have a bunch of boutique mic preamps or an analog console, Apollo 16 may be the choice for you. Apollo 16 has sixteen line level ins and outs all on D-Sub connectors. Use these with cables that terminate with XLR or TRS to connect to consoles, 500 series frames, summing buses, etc. Apollo 16 also has one AES/EBU in and out, XLR outs for control room monitors, and Wordclock I/O. MADI connectivity is also featured but not activated at this time. Like the Apollo 8p, Apollo 16 is only available as a Quad DSP.

Apollo Quad Firewire

As you may have noticed, all of our Apollo 8 rackmount units are exclusively Thunderbolt and for use on Mac computers. For the Windows user or Mac user that does not have Thunderbolt ports you can opt for the Apollo Quad Firewire. It has the same I/O complement as Apollo 8 Quad, but comes with Firewire 800 and can be upgraded to Thunderbolt with the optional card.

Unison Technology

Apollo 8 comes equipped with four Unison-enabled mic preamps, letting you track projects with colorful mic preamp sounds from Neve, API, and Universal Audio. An Apollo breakthrough, Unison technology nails the tone of these sought-after tube and solid state mic preamps — including their impedance, gain stage “sweet spots,” and component-level circuit behaviors. The secret to Unison is its hardware-software integration between Apollo’s mic preamps and its onboard UAD-2 processing. Simply place a selected tube or solid state preamp plug-in on your desired mic input, and record in real time through stunning emulations like the bundled UA 610-B Tube Preamp plug-in, or the Neve 1073 and API 212L.

Apollo 8 is further enhanced by adding Unison technology to its front-panel Hi-Z instrument inputs, giving you dead-on impedance and gain matching for new stompbox models like the Ibanez Tube Screamer TS808.

What is Unison? Unison is an exclusive analog/digital integration system that’s built into every Apollo microphone preamplifier. It’s the first and only way to truly emulate classic analog mic preamp and pedal behaviors in an audio interface. Unison is an audio processing breakthrough that starts right at the source, the input stage, allowing Apollo’s mic preamps to sound and behave like the world’s most soughtafter tube and solid state preamps — including their all-important impedance, gain stage “sweet spots,” and component-level circuit behaviors. Apollo’s mic preamps are designed for high resolution, ultra-transparent translation from microphone to converter. This clean hardware design is the foundation for adding software color with UAD plug-in processing. Unison-enabled UAD preamp and pedal plug-ins reconfigure the physical input impedance, gain staging response, and other parameters of Apollo’s mic preamp hardware to match the emulated preamp’s hardware design characteristics. Because the hardware and software are intricately unified, Unison provides continuous, realtime, bi-directional control and interplay between Apollo’s physical mic preamp controls and the software settings in the Unison plug-in interface. Controls on Apollo’s front panel dynamically adjust the Unison plug-in’s parameters to match the target preamp/pedal behavior. Correspondingly, changing a setting in the Unison plug-in interface will modify Apollo’s front panel settings. Because Unison can be active on more than one mic channel, a complement of premium mic preamps is available concurrently.

Apollo Unison

Unison technology enables these Apollo features, all with Realtime UAD Processing:

  • Alternate microphone preamplifier sound – Apollo’s ultra-transparent mic preamps inherit all the unique sonic and input characteristics of the emulated hardware preamp or pedal, including the mic, line, and Hi-Z inputs.
  • Realistic tandem control – Unison facilitates seamless interactive control of Unison preamp plug-in settings using Apollo’s digitally-controlled hardware and/or the plug-in interface. All equivalent preamp controls (gain, pad, polarity, etc) are mirrored and bi-directional. The preamp controls respond to adjustments with precisely the same interplay behavior as the emulated hardware, including gain levels and clipping points.
  • Hardware input impedance – All Apollo mic preamps feature variable input impedance in analog hardware that can be physically switched by Unison plug-ins for physical, microphone-to-preamp resistive interaction. This impedance switching enables Apollo’s preamps to physically match the emulated unit’s input impedance, which can significantly impact the sound of a microphone. Because the electrical loading occurs on input, prior to A/D conversion, the realism is faithful to the original target hardware preamp.
  • Tactile gain staging – Apollo’s front panel preamp knob can independently adjust all gain and level parameters available within the Unison plug-in via Gain Stage Mode. The gain stage being adjusted can be remotely switched via Apollo, so multiple gain levels and their associated colorations can be tuned from the hardware knob for precise physical tactile control, all without using the Unison plug-in’s software interface.

Other Features

Every Apollo interface includes our Console Recall plug-in. Console Recall is a DAW plug-in in VST, RTAS, AAX 64, and Audio Units formats. It is inserted and used within host DAWs just like any other plug-in. The primary function of the Console Recall plug-in is to store the current Console configuration within the DAW via the SYNC (synchronize) switch in the plug-in. It can also be used to view and adjust Apollo’s monitor output level, mono, and mute states without having to leave the DAW. When a DAW project containing the Console Recall plug-in is saved and the SYNC switch is enabled in the plug-in, the state of the Console application is stored within the Console Recall plug-in. When the DAW project file is subsequently reloaded, Console is automatically restored to the previous settings state, regardless of any changes to Console or Apollo that were made in the interim. Since plug-in settings are saved within DAW project files, using SYNC enables Console’s current state to be stored within the DAW project file without saving or loading Console sessions presets via the Console Sessions functions.

Apollo’s powerful Flex Driver feature enables virtual mapping of I/O routes, channel counts, and labels at the Core Audio driver level. Flex Driver makes it possible to remap Apollo’s driver inputs/outputs to any Core Audio inputs/outputs, offering the ultimate in I/O routing flexibility when using any DAW. The driver labels for Apollo’s I/O can be renamed so that DAW inputs and outputs can use custom names. With Flex Driver, channel input and output selectors within a DAW can be (for example) “Neve 1073” instead of “Input 1.” Some DAWs restrict the number of I/O channels that can be used. With Flex Driver, it’s possible to specify exactly which I/O is seen by the DAW, even if the available Apollo I/O exceeds the DAW’s maximum channel I/O count. Customized I/O templates can be saved and loaded to or from disk as presets for future recall and/or sharing with other Apollo users.

By default, monitor output levels are continuously variable with Apollo's volume control. However, the monitor outputs can be set to completely bypass the monitor level circuitry and operate at a fixed reference level. This feature is set with the MONITOR OUTPUT GAIN menu in the Hardware panel within the Console Settings window. This feature routes the signal directly from the D/A converters to the monitor outputs for the purest signal path when level control is not needed (for example, when connecting the monitor outputs to an external monitor controller).

Apollo’s device drivers carry various virtual (software only) input and output channels in addition to those directly associated with the hardware inputs and outputs. The virtual channels consist of Console’s virtual inputs, Console’s virtual outputs, and Console’s aux and monitor bus outputs. Virtual I/O facilitates highly flexible signal routing via the DAW, without needing to reach behind the gear rack for manual cable patching. Additionally, because the virtual I/O channel audio streams are in the digital domain, a pristine audio signal path is maintained without requiring additional A/D–D/A conversions. The virtual input channels enable any DAW output to be routed directly into Console’s virtual inputs so Realtime UAD Processing with UAD plugins can be applied to the DAW signal(s). This feature is particularly useful when performing live with virtual software instruments inserted in the DAW, because the throughput latency associated with I/O buffering is reduced in this configuration.

Universal Audio DSP Accelerators

If you want to experience UAD-2 plug-ins in your DAW and want to continue using your interface or if you own an Apollo rig and would like to add more DSP for mix, a UAD-2 DSP Accelerator is the way to do it.

UAD-2 DSP Accelerators are available in four different form factors: PCIe, Satellite Firewire, Satellite Thunderbolt, and Satellite USB. Which one you select is based on both your connectivity and computer type. Here’s a breakdown of which works with what:

  • PCIe compatible with available PCIe slots in Mac or PC computers
  • Satellite Firewire compatible with Mac or PC computers with an available Firewire 800 or 400 port or on Macs with a Thunderbolt port and a Thunderbolt/Firewire adapter
  • Satellite Thunderbolt compatible with Mac only computers with an available Thunderbolt port
  • Satellite USB compatible with Windows computers with an available USB 3.0 Superspeed port

How many plug-ins you can run simultaneously depends on a number of factors but the most important is how many SHARC DSP chips are in each UAD-2 Accelerator. Quad products contain 4 SHARC chips and Octos have 8 SHARC chips. Actual number of plug-in instances will vary based on Firewire bandwidth (if applicable), session sample rate, and how DSP intensive the plug-in is. Please reference our UAD-2 instance chart for more information.

Every UAD-2 DSP Accelerator includes the Analog Classics Plus bundle:

  • UA 610-B Tube Preamp and EQ
  • Fairchild 670 (Legacy)
  • UA Precision Enhancer Hz
  • 1176SE/LN Classic Limiting Amplifiers (Legacy)
  • Pultec Pro Equalizers (Legacy)
  • Teletronix LA-2A Classic Leveling Amplifier (Legacy)
  • Precision Mix Rack collection
  • Realverb Pro

With our current lineup of UAD-2 Accelerator models you can also opt for a Custom bundle. A Custom also includes the Analog Classics Plus bundle and they come with the flexibility of choosing any three additional plug-ins. If you’re not sure what you might want, don’t sweat it because you’ll have full access 14-day demo periods on every plug-in and a whole 45 days to decide.

Universal Audio Signal Processors/Mic Preamps

Universal Audio may be well known these days for plug-in emulations but it all started back in the 1960s with analog designs. The iconic 1176LN is still found in many recording studios. In fact, try searching “recording studio” images and you’ll find photos of multiple 1176LNs in just about every outboard rack. Most of the analog product line is still manufactured by hand in California, including the 1176LN, LA-2A, 6176, 2-610, LA-610, and Solo 610. And the LA-2A is still wired completely point-to-point just like it was in 1967.

FET or Opto?
While both compressor designs are classic, each offers a little something different. The 1176LN uses a FET for its gain control element, while the LA-2A is electro-optical. Besides the differences between solid state and tube, these different gain control elements are responsible for the compression characteristics of their respective units. A FET compressor can be unbelievably fast in its attack time, making it fantastic for individual or drum group processing. However, it can also be backed off and used for vocals such as on tracks by Adele and Michael Jackson. The LA-2A on the other hand, is not nearly as quick in its attack but its two-stage release results in a very transparent quality that is perfect for vocals or less transient sources.

Universal Audio 1176LN Classic Limiting Amplifier Compressor Limiter Universal Audio 1176LN Classic Limiting Amplifier Compressor Limiter

6176 and LA-610MkII Channel strips
If you’re considering a channel strip, note that the 6176 is part 610 preamp and part 1176LN. You can set the Join/Split switch to Join and process a vocal or instrument completely. For even more versatility, set the switch to Split and use the 610 preamp and the 1176LN sections on two separate sources. The LA-610MkII contains the same preamp section as the 6176, but instead features an electro-optical compressor based on the LA-2A. The lack of a Join/Split mode means you’ll need to use all this tubey goodness on a single source.

What’s with the Line inputs?
All Universal Audio preamps and channel strips feature line level inputs in addition to microphone inputs. With most preamps you only get to utilize them in the tracking phase of your project because they are no longer useful in mixing. The selectable line level input allows you to use your preamps in the mix stage by sending busses like drums, vocals, bass, etc. back through the preamp with proper gain staging. Think of a 2-610 stereo preamp as both a two channel pre and a tube color box to run your entire mix through and get some vintage vibe.

If you’re looking to add more mic preamps to your Apollo or other interface via ADAT, the 4-710d is a solid choice. With 4 mic preamps that can be dialed between solid-state and tube gain plus each with a compressor circuit, up to two 4-710d units can be chained together for eight channels down a single ADAT cable.


Arrow is the latest interface from Universal Audio. It is very much like an Apollo Twin, but different enough to be considered its own category. With two mic preamps, DI instrument input, speaker and headphone outputs, Arrow is a perfect fit for artists that want Universal Audio power, flexibility, and quality without the recording engineer features that don’t fit their needs or budget.

Arrow is the first Thunderbolt 3 audio interface. This means it is well ahead of the curve, so you’ll need a Mac or PC with a built-in Thunderbolt 3 port. Where we take advantage of this new technology is bus-power. There is enough voltage on Thunderbolt 3 to omit a wall wart power supply and simply run off the power from the computer. This increases Arrow’s portability and flexibility to record just about anywhere when using with a laptop. Take note that due to Thunderbolt 3 spec, you must have a USB-C port with Thunderbolt 3 protocol. USB-C equipped computers are not necessarily synonymous with Thunderbolt 3 and adapters will not work. Please check your computer’s specifications first.

Arrow incorporates the same UAD-2 processing as our Apollo line, but is only available as a Solo (one processing chip). A good insight into how many UAD-2 plug-ins you can run on a Solo can be found on our UAD-2 Instance Chart. This means Arrow is capable of the same Apollo workflow of sub 2ms latency tracking to your DAW software of choice with plug-ins in the Console application. The included Console app eliminates the latency associated with DAW I/O buffering that makes monitoring problematic for the artist. By removing the DAW's "software input monitoring" feature from the monitoring signal flow altogether, the need to adjust I/O buffer sizes and latency is no longer an issue.

Like it’s Apollo siblings, Arrow also features Unison enabled mic preamps and DI input. Please see the Unison tab in this buyer’s guide for more information on the power of Unison technology.

OX Amp Top Box

Universal Audio’s engineers set out to design a reactive load box that retains the tone, dynamics, and feel of your tube guitar amp, no matter how much its power is attenuated. Your guitar amplifier will “see” OX as an actual speaker, with continuously variable impedance and response, so you don’t lose a drop of tone or playing dynamics.

OX’s front-panel, six-position RIG control allows you to quickly choose from complete setups: emulated speaker cabinets, close mics, ambient room mics, and up to four simultaneous studio effects. OX is the only guitar recording system to offer a complete selection of expertly placed room mics, giving you the authentic experience of pushing air while recording your cranked amp in a world-class tracking room.

UA’s groundbreaking Dynamic Speaker Modeling faithfully emulates speaker breakup, drive, and cone cry, an essential ingredient to authentic tube amp tones. Using the Speaker Breakup knob in the OX app, you can control the harmonics and sonic complexity that occurs only at certain frequencies and volume levels on various speakers — far beyond a static Impulse Response system — giving you the same sonic phenomenon that occurs with a real speaker cabinet.

The OX software app offers slick, intuitive control over all of OX’s RIG settings via Wi-Fi, letting you tweak, store and recall hundreds of presets from your iPad or Mac. Not only does OX Amp Top Box feature a front-panel headphone jack for silent practice with your cranked tube amp, it also sports a bevy of connections for all kinds of recording and live workflows. Stereo S/PDIF digital outputs via RCA and optical TOSLINK, as well as balanced TRS stereo line outputs with front panel level control, give you the necessary connections for studio monitors, DAW, or live mixing console inputs.