With the release of the new Apollo x4, UA keeps the hits coming with a revised and expanded desktop interface utilizing the recent conversion upgrades found in its rackmount sibling "x" range. At a little less than twice the footprint of the Apollo Twin [Tape Op #121] form factor, the x4 offers twice the I/O and utilizes a high-bandwidth Thunderbolt 3 port for connection to modern Mac computers. The x4 is backward compatible with Thunderbolt 1 or 2 on Macs with the proper adapter, and machines running Windows 10 (and up) with Thunderbolt 3 cards are supported.

First, a quick detour to talk about an essential update to the UA Console software: recent updates to the UAD software platform allow for Channel DSP Pairing; stretching the available resources across multiple SHARC processing cores. Put simply, Channel DSP Pairing lets you build more substantial chains of UAD plug-ins on Console inputs when tracking in real-time. More dedicated processing resources for tracking means more happy engineers. Channel DSP Pairing is a free upgrade that benefits not only the "x" range of Apollos but every Apollo except the first-generation FireWire-enabled models. This is huge. With a few easy tweaks of the new settings in Console, you can now optimize Console sessions towards either more virtual channels or larger plug-in chains.

Despite this added convenience, there are tracking caveats and a few gotchas that weren't readily apparent at the outset (but ultimately made more sense as I got used to this new paradigm). For instance, Channel DSP Pairing is not available at the highest sample rates of 176.4 and 192 kHz, and is only applicable to the DSP available in Apollo units themselves (UAD-2 Satellites don't add any additional Channel DSP Pairs to the overall count). Also, DSP can only be paired within each Apollo unit individually. These minor restrictions aside, this new feature works transparently and automatically when enabled, plus you can leverage all of that multi-core horsepower for real-time low-latency tracking – I found this especially helpful during overdubbing stages. I could stack up Console strips to my heart's content (within reason, of course – Console will still indicate if you've exceeded DSP resources).

Managing all of this Apollo horsepower can sometimes seem a bit mystifying at first, but the UA support site is a tremendous resource, with lots of clear and accessible documentation. Semi-pro tip: I'd recommend starting with the "Managing DSP Resources" article on the UA support site.

While we're talking DSP horsepower, I wanted to mention the latest rev of UAD-2 Satellites, now featuring Thunderbolt 3 connections. UA was kind enough to send us one of their new external DSP accelerators in the heftiest variant available, with eight SHARC processors inside. A modest and compact piece of gear on the outside, the Satellite has rapidly become a must-have in my mixing and mastering workflow. Using it to supplement my onboard Apollo DSP is plug and play, as the Satellite has two Thunderbolt 3 ports, allowing it to be positioned between either multiple Apollos, or (as in my case) between my rig and a Thunderbolt 3 dock. I tested connectivity and throughput with the TS3 Plus Thunderbolt 3 dock from CalDigit [#104], and one of the latest MacBook Pro laptops – everything worked as expected. The OCTO Satellite isn't flashy – at about the size of a cigar box, it has no external controls or functions beyond a power switch – and no I/O beyond the two Thunderbolt 3 ports and the power supply connection. Despite its modesty, having the OCTO in my setup is the single most significant change to my workflow since I've started using UAD plug-ins. The OCTO Satellite is like adding a supercharger to an Apollo – or a third-stage rocket booster. I'm now mixing with a much greater sense of freedom of choice, and having multiple instantiations of processor-hungry plug-ins (such as the AMS RMX16 or Thermionic Culture Vulture) is no problem for this heavy-lifter.

Okay, back to the x4. The x4 comes in only one UAD DSP "size": the 4-core Quad-core processor version. So, as an owner of the previous-gen Twin Mk II (w/ the same Quad-core DSP inside), I had to consider if an upgrade was truly needed. There are two factors at play with the x4 that make the answer relatively straightforward for me: the dual headphone cue outputs and the increased Unison preamp count (up from two in the Twin, duh). Having only one headphone output and two Unison mic pres in the Twin could sometimes limit its usability for say, mobile drum tracking, but the x4 feels like "the porridge is just right." I could certainly make a case for UA's latest and greatest AD/DA conversion on that list. But how I intend to use the x4 (primarily as a mobile-rig extension my rackmount x-gen Apollo system) renders the previous two features much more significant. Having the ability to build two independent cue mixes, and track through four Unison emulations gives me much more flexibility with my on the go mobile tracking. The minor tradeoff is that the x4 takes up a little more room in any mobile go-bag, but it'll still easily fit in a backpack, even with the power supply. The design language and metering follows the previous generations of Apollo Twins, but I did notice that the case ventilation of the x4 hardware seems to be improved.

Be advised, UA doesn't include a Thunderbolt 3 cable with either the Apollo range or the UAD-2 satellites, and not all Thunderbolt 3 cables are built alike! When considering any Thunderbolt 3 Apollo or UAD-2 accelerator, I would do some research in choosing cabling: I landed on a high-quality and affordable T-bolt 3 cable from CalDigit that does the trick nicely. But the new x4: It's an Apollo. What's not to like? "That price tag!" I hear you yelling from the back. Fair point. But for engineers invested in the UA ecosystem, consider that its little brother, the Apollo Twin X, is a mere $400 less for effectively half the I/O – or that the rackmount Apollo x6 is $400 more, and has only two Unison inputs as well. In summary, I dig the x4. As a mostly-mobile premium interface, it stacks up quite nicely against its siblings in the wonderfully full house that is the Apollo family.

Tape Op is a bi-monthly magazine devoted to the art of record making.

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