Universal Audio Apollo X4 Gen2 Analog Classics

The versatility of an Apollo with more extensive connectivity

The Apollo x4 takes the Apollo Twin approach while providing more room for simultaneous connections. Its four preamps and second headphone output meet the needs of musicians working together, without requiring a rackmount interface. It therefore strikes a balance between a compact footprint and flexible routing.

Compared with the first generation, the Gen2 notably benefits from improved digital-to-analog conversion and monitor outputs, as well as the Auto-Gain level-setting assistance function. The Bass Management and Apollo Monitor Correction software features also enhance its environment, without being exclusively reserved for Apollo Gen2 models.

For vocals, instruments, and multi-musician sessions

This Thunderbolt audio interface is suitable for singer-songwriters, producers, and project studios looking to record multiple microphones. A vocal accompanied by a stereo guitar, several instruments, or a small acoustic ensemble can naturally fit into a four-preamp setup. The two headphone outputs make it possible to prepare separate monitor mixes for the performers.

For guitarists and bassists, the two front-panel Hi-Z instrument inputs simplify direct connection. When requirements increase, the optical connections provide a digital expansion option: up to eight additional channels via ADAT at 44.1 or 48 kHz, with fewer channels available at higher sample rates.

Unison and UAD Console: shaping the sound from the start

Interaction between analog preamp and emulation

Unison technology is not limited to applying a color after recording. With a compatible plug-in placed in the dedicated slot, it adapts the input impedance and the behavior of the Apollo preamp’s gain stages. This allows you to shape the response and saturation of the selected model during recording, rather than building everything during mixing.

Real-time processing for inspiring monitoring

Integrated UAD processing lets you prepare a monitoring chain with preamp, compression, or EQ in UAD Console. The musician hears an already processed sound while playing or singing. This setup brings computer-based recording closer to working on a console, with centralized routing and monitoring.

The Analog Classics edition provides a selection of more than 30 plug-ins, including Teletronix LA-2A and UA 1176 processing, Pultec Legacy equalizers, UA 610 preamps, and Pure Plate Reverb. It differs from the Analog Classics Pro edition, whose collection is more extensive: the latter’s models are therefore not all included here.

More practical level and monitoring adjustment

Auto-Gain assists with setting input levels, including with certain compatible Unison preamps. Apollo Monitor Correction, meanwhile, makes it possible to integrate Sonarworks room correction. Its use requires the appropriate software and licenses, as well as a compatible measurement microphone for calibrating the speakers.

Technical specifications

Format	Thunderbolt 3 desktop audio interface.	Optical S/PDIF	2 channels, up to 96 kHz.
Maximum capacity	12 inputs and 18 outputs.	Included plug-in collection	UAD Analog Classics, more than 30 titles.
Integrated processing	UAD-2 QUAD Core.	Control and mixing application	UAD Console.
Conversion resolution	24-bit, up to 192 kHz.	Apollo Monitor Correction by Sonarworks	appropriate software, licenses, and measurement hardware required.
ADAT	8 channels at 44.1/48 kHz, 4 at 88.2/96 kHz, and 2 at 176.4/192 kHz.