Poised to be the center of a project studio or highly flexible mobile rig, the Universal Audio Apollo x4 Heritage Edition desktop 12x18 Thunderbolt 3 audio interface combines the sound, feel, and flow of analog studio recording with powerful QUAD Core real-time UAD processing and a robust bundle of 34 stellar UAD plug-ins.

Furnished with elite-class 24-bit / 192 kHz conversion akin to the popular Apollo X rackmount interfaces, the Apollo x4 gives musicians, producers, songwriters, and audio engineers the appreciable value of crystal-clear, high-resolution recording and mixing with low distortion (-117 dB) and immense dynamic range (127 dB).

The interface features four XLR-1/4" mic/line combo inputs and two 1/4" Hi-Z inputs, all with Unison integration for precise UAD emulations of classic analog preamps. Impart vintage character of your choosing on microphone and instrument recordings while bypassing the unpredictable nature of old equipment.

Thanks to the switchable low-cut filter, pad, polarity inversion, 48V phantom power, and stereo linking on each analog input, you can efficiently optimize your incoming signals with straightforward buttons on the Apollo x4's face. In addition to the four primary analog inputs, you can record up to eight more channels by connecting external preamps with ADAT or S/PDIF optical outputs to the TOSLINK optical input port on the Apollo x4. An optical output is also featured on the Apollo x4, allowing it to route up to eight channels from your DAW to a digital mixer, headphone distribution system, or external D/A converter.

The built-in QUAD Core processing allows you to monitor and record audio using classic analog emulations with near-zero latency and no burden on your computer's CPU. The plug-in bundle included with the Heritage Edition empowers you with 34 top-notch plug-ins ranging from vintage compressor and EQ collections to virtual guitar/bass amps, time-based processors, and tape emulation. The included Console application provides control and recall of all interface and UAD plug-in settings including channel-strip presets, drag-and-drop functionality, and dynamically resizable windows.

Mac and Windows drivers ensure compatibility with all major DAWs including Pro Tools, Logic Pro, Cubase, Ableton Live, and more. The interface also integrates seamlessly with LUNA, Universal Audio's free Mac-based, single-window recording system with unlimited track counts and full Audio Units plug-in support.

The Apollo x4 offers a comprehensive monitor section with talkback functionality and dedicated front-panel controls for Alt Speakers, Dim, and Mono functions, as well as input and output metering capabilities. In addition to the dedicated stereo monitor feed and two front-panel headphone outputs (great for handling multiple cue mixes), four 1/4" line outputs are available for connection to a second set of monitors and outboard processors.

At any point, you can increase the power and capability of the Apollo x4 through integration of qualified Universal Audio hardware. Up to four Apollo interfaces and six total UAD-2 devices can be combined, allowing Thunderbolt users the ability to expand their I/O and DSP without abandoning the Apollo x4. The Thunderbolt 3 port is backward compatible with Thunderbolt 1 and 2 via a qualified adapter (available separately).

Musicians, Producers & Project Studios    AC Powered, Mac/Windows    4 Mic/Line Preamps, 2 Hi-Z Inputs    2 Headphone and 6 Line Outputs    24-Bit / 192 kHz AD/DA Conversion    QUAD Core Real-Time UAD DSP    48V, Low-Latency Monitoring    Monitor Section with Talkback Mic    Optical ADAT or S/PDIF Input    34 UAD Plug-Ins & Mac Recording Software

The Heritage Edition features the same Apollo x4 interface found in the standard edition but with more plug-ins. The standard Apollo x4 includes the Realtime Analog Classics Plus bundle (16 plug-ins), and the Heritage Edition adds 18 more plug-ins for a total of 34 revered UA-powered plug-ins.

• Track, overdub, and mix with high-resolution AD/DA conversion and DSP-powered plug-ins
• QUAD Core UAD processing for tracking through models of vintage compressors, EQs, tape machines, mic preamps, and guitar amps, with near-zero latency and no burden on your computer’s CPU
• Unison technology nails the tone of sought-after tube and solid-state mic pres including their input impedance, gain-stage sweet spots, and the component-level circuit behaviors of the original hardware
• High-speed Thunderbolt 3 connectivity for Mac and Windows computers (Thunderbolt cable available separately)
• Convenient desktop form factor with reliable AC powering (external power supply included)
• Free, industry-leading phone/online technical support from knowledgeable audio engineers

• 12x18 audio interface with four Unison-enabled microphone preamps (via XLR-1/4" combo mic/line inputs), providing emulations of classic analog preamps with near-zero latency
• Two front-panel, Unison-enabled 1/4" Hi-Z inputs for direct connection of guitars, basses, or keyboards
• Stereo 1/4" monitor output and two independent 1/4" headphone outputs, each with adjustable level
• Four additional 1/4" line-level outputs, may be used for alternate monitor outputs or analog outboard processors
• Add up to eight extra input channels via one TOSLINK optical ADAT port (may alternatively be used for stereo S/PDIF)
• TOSLINK optical output supports ADAT or S/PDIF format for sending up to eight channels from your DAW to a digital mixer, headphone distribution system, or external D/A converter

• Built-in monitor controller with monitor remote functions and mono, mute, dim, and alt monitor controls
• Integrated talkback and cues for easy communication and slate functionality
• Comprehensive front-panel metering and fast, intuitive controls, no menu-diving required

• Cascade up to four Thunderbolt-equipped Apollo interfaces and six UAD-2 Thunderbolt devices for expanded I/O and DSP
• Expand your studio with an Apollo X rackmount unit (available separately), so you can use your Apollo x4 as a desktop monitor controller with additional I/O and DSP power
• Backward-compatible with Thunderbolt 1 and 2 via a qualified adapter (available separately)

Includes Realtime Analog Classics Plus plug-in bundle plus 18 additional plug-ins to complete the compressor, EQ, and preamp collections and provide tape emulation and another reverb (plug-ins support VST, RTAS, Audio Units, and AAX 64-bit for compatibility with all major DAWs):

• UA 610-A Tube Preamp and EQ (Vintage)
• UA 610-B Tube Preamp and EQ (Modern)
• Marshall Plexi Classic Guitar Amp
• Ampeg SVT-VR Classic Bass Amp
• UA 1176LN Limiting Amplifier (Legacy)
• UA 1176SE Limiting Amplifier (Legacy)
• UA 1176 Classic Limiter Collection (1176LN Rev E, 1176 Rev A, and 1176AE 40th Anniversary Edition)
• Pultec EQP-1A EQ (Legacy)
• Pultec MEQ-5 EQ (Legacy)
• Pultec Passive EQ Collection (EQP-1A, MEQ-5, and HLF-3C)
• Teletronix LA-2A Leveling Amplifier (Legacy)
• Teletronix LA-2A Classic Leveler Collection (LA-2A Silver, LA-2A Gray, and LA-2)
• Teletronix LA-3A Audio Leveler
• Helios Type 69 Preamp and EQ Collection (Helios Type 69 and Helios Type 69 Legacy)
• V76 Preamplifier
• Raw Distortion
• Fairchild 670 Compressor (Legacy)
• Fairchild Tube Limiter Collection (Fairchild 660 and Fairchild 670)
• Precision Enhancer Hz
• Precision Channel Strip (Precision Mix Rack Collection)
• Precision Reflection Engine (Precision Mix Rack Collection)
• Precision Delay Mod (Precision Mix Rack Collection)
• Precision Delay Mod L (Precision Mix Rack Collection)
• Pure Plate Reverb
• RealVerb Pro Custom Room Modeler
• UA Oxide Tape Recorder

• Apollo Heritage Editions include plug-ins featured in UAD Spark, UA's subscription plug-in collection that runs natively on Mac—no UA hardware required
• With UAD Spark, you can expand your plug-in processing power, balancing your DSP load between Apollo and your computer's onboard processing
• Receive the 1176 Classic Limiter Collection, Teletronix LA-2A Classic Leveler Collection, and Pure Plate Reverb
• Current owners of any plug-ins available in UAD Spark will receive the UAD Spark versions free

• Works with all major DAWs including Logic Pro, Ableton Live, Pro Tools, and more
• Apollo x4 becomes a fully integrated recording system with LUNA, a powerful free recording application for Mac from Universal Audio
• Bolstered by Accelerated Realtime Monitoring, LUNA lets you track and mix using an intuitive single-window workflow with unlimited track counts, full Audio Units plug-in support, and access to a suite of exclusive LUNA Instruments and Extensions such as Studer multitrack tape and Neve Summing

Related Questions and Answers

Q: 1. Can this device work with a hub like "Belkin Connect Thunderbolt 4 Core Hub" being connected to it instead directly to a Mac?"

A: Technically, you could connect the Universal Audio Apollo Solo Heritage Edition Desktop 2x4 Thunderbolt 3 Audio Interface with SOLO Core Real-Time UAD Processing to a Mac via a Thunderbolt 4 hub. However, I would not suggest doing this. A hub like this essentially has its own computer inside, so passing audio through it before it hits your computer could introduce unwanted artifacts into your recordings.

Q: 2. Can it work with mac computers?

A: B&H # UNAPLSHE is the Universal Audio Apollo Solo Heritage Edition Desktop 2x4 Thunderbolt 3 Audio Interface that is compatible with Mac computers. B&H # UNAPLSUHE is the Universal Audio Apollo Solo USB Heritage Edition Desktop 2x4 USB Type-C Audio Interface for Windows.

Q: 3. Which cable is suitable to connect the device to my computer (Windows)?

A: The Universal Audio Apollo Twin X DUO Heritage Edition Desktop 10x6 Thunderbolt 3 Audio Interface can be connected to a Windows computer equipped with Thunderbolt 3 by using a Thunderbolt 3 cable like the Xcellon Thunderbolt 3 Cable - 1.6', 40 Gb/s (B&H # XCTB354005) or the Belkin Thunderbolt 3 USB Type-C Male Cable - 3' (B&H # BEUSBCC3BLK).

Q: 4. Can the Solo drive 250 Ohm headphones?

A: Yes they will drive 250 ohm headphones.

Q: 5. Then, if I have this interface connected to a mac mini via Thunderbolt and use ProTools, how can I add preamps/inputs?

A: There is no way to add preamps or physical inputs to the Apollo Solo Heritage. For that, you would need an Apollo Twin that has an ADAT port so that you can add an ADAT preamp for additional channels than what is included with the Apollo Twin. Or, you can add tracks in Pro Tools and record those tracks separately, while listening to the existing audio tracks already recorded, when using the Apollo Solo Heritage.

Q: 6. Approximately how much watts or milliwats of power can this provide to my Beyerdynamic Dt 1990 pro headphones?

A: The specific information regarding the headphone output impedance or power on the Antelope Zen Q Synergy Core Desktop 14x10 Thunderbolt 3 Audio Interface is not made publicly available by the manufacturer.

Q: 7. Does this work well with newer Macs using USB-C?

A: It depends on what you define as "newer". USB-C refers to the connector type, not the protocol used. The current lineup of Macs all have Thunderbolt 3 on USB-C ports, so yes it works with all of these, as well as older Macs with Thunderbolt 1, 2 ports. Some Macs as recently as 2017 (MacBook and Air) had USB-C ports that did not have Thunderbolt going through them. Apollo x8 works with Thunderbolt 1, 2, or 3 but you must make sure that any Mac that has USB-C connectors is actually using Thunderbolt protocol.

Q: 8. Looking to use interface for phone interviews for radio broadcast and recording. I notice the XLR port is not standard...will this call for an adapter or different cable?

A: Hi. I have one of these units. May I ask, what you mean by not standard? What connector do you need? There is a 3 pin female XLR for audio into the unit and a 3 pin male XLR for audio out of the unit. They are below the keypad.

Q: 9. How many audio channels over USB are supported in class compliant mode? Can one route eg 32 channels from USB to Madi and then another 32 from adat to madi?

A: USB 2.0 (44.1 to 48 kHz): 64 in/out USB 2.0 (88.2 to 96 kHz): 32 in/out USB 2.0 (176.4 to 192 kHz): 24 in/out

Q: 10. Approximately how much power willl this provide to my Beyerdynamic Dt 1990 pro 250 ohm headphones in watts and milliwatts? Is the interface enough power alone with out an after market headphone amp?

A: I contacted technical support at Antelope directly and while they do not have a specification for the power of the headphone output on the Zen Q Synergy Core Desktop 14x10 Thunderbolt 3 Audio Interface, they did tell me that they had previously tested this interface with different 250 ohm headphones and felt that the volume level was sufficient for general monitoring purposes. However, what each person considers sufficient volume is subjective and what works for one person may not work well for another person. If you will want to have high volume or very strong bass, then you will most likely want to use a separate headphone amp with the Beyerdynamic DT 1990 Pro headphones.