Review: Focusrite Liquid 4PRE & Plug-Ins

It’s not often we review a product that’s been circulating around the globe for this long, but I’ve been dying to have a play with Focusrite’s Liquid 4Pre since its release – nearly two years ago now. That’s my personal reason for airing the unit in AudioTechnology; the more pertinent reason, however, is the recent release of dedicated RTAS plug-ins that drive the unit directly from both ProTools HD and LE. At the same time I’ve been investigating the recently released TDM plug-in versions of the Liquid Mix. First things first though, let’s have a look at what the Liquid 4Pre is capable of, and a little bit of background on the technology it employs.

The Liquid series of products utilise ‘Dynamic Convolution’, a system not dissimilar to the one that builds convolution reverbs. In both instances, impulse audio files are played through a piece of analogue recording equipment at every possible gain setting, and the resulting impulse responses are used by the digital signal processing engine to recreate the sound of the original piece of equipment. Focusrite has been partners with the originators of this technology, Sintefex, for almost a decade now, and the Liquid lineage is a direct result of this partnership. Previous to the Liquid 4Pre was the Liquid Channel, a heftily priced and spec’ed channel strip that emulates preamps, dynamics processors and EQ units. The Liquid 4Pre dispenses with the EQ and dynamics processing aspects and is merely a set of four preamps – but when I say merely, the 4Pre system could arguably be the only preamps you’ll ever need.

TOP 40

The 4Pre comes loaded with 40 finely crafted preamp simulations. These cover a wide range of classic preamp designs used throughout recording history, interspersed with a good number of modern classics. Inevitably, Focusrite has included in this Top 40 emulations of its own ISA, Red, and Green series preamps – which were no doubt guinea pigs early on in the product’s development. These have been given software titles synonymous with the original product names. Not so with the other 30-odd emulations unfortunately, the names of which are quite esoteric and indecipherably cryptic, due no doubt to the fact that permission was never acquired to use them. This is my primary bugbear with the entire Liquid 4Pre – everyone wants to know what the names correspond to in the end, and the deception seems like farce.

Consequently the Amek Pure Path is represented by the name ‘The Gov’. The API 3124 is ‘Tranny H’, and the Drawmer 1960 is bestowed the rather odd moniker of ‘Wasp 1’. Sure you don’t actually have to know what an emulation is emulating when dialling up the options to decide on a particular sonic character – but it’d be nice to be pointed in the right direction when making your preamp choices. Eventually you’d come to memorise all the nicknames, but it’s a lot of mucking around getting there.

AUTOPILOT

Driving the 4Pre is largely self-explanatory. The four rotary encoders across the front panel are dedicated to each of the four preamp paths, and each of these offers a pushbutton action for selection of settings. For example, press the ‘Preamp Select’ button and the encoder will take you through the emulation options. Press the ‘Harmonics’ button and the encoder will introduce harmonic distortion to the emulation in 15 levels. Go past eight and you’re adding third- and fifth-order harmonics. Stay below that and you’ll confine yourself to second-order harmonics only.

With neither of these buttons engaged the encoder simply provides gain control, with a generous 80dB of boost on offer – a feat many of the original devices never stood a chance of delivering. Aside from the phantom power, phase, and 75Hz high-pass filter buttons, each preamp houses a sweet little function called ‘Session Saver’. This doo hicky will register whether one of your preamps has clipped, and if it has, it will reduce its gain by one dB. Clip it again and the gain will drop another dB. A nice touch – handy if you’ve got a lot going on during a tracking session or live-to-air broadcast for instance.

The rear of the rather heavy 4Pre is brimming with I/O options. Aside from XLR inputs for the four mic preamps themselves, there are separate XLR line inputs and outputs for each channel, two AES/EBU outputs, AES/EBU input, wordclock I/O and ADAT optical ports, which can be used to gang multiple 4Pres together. Finally, an ethernet port provides communication with the freely supplied control software, or the recently released RTAS control plug-ins. It’s a comprehensive back panel indeed.

PLUG ME IN

The plug-ins work flawlessly. They take up a tiny amount of screen real estate and are without doubt the only sensible option when driving the 4Pre alongside any ProTools system. Like the standalone control software, the plug-ins communicate with the 4Pre via 100base-T ethernet, so changes made with the plug-in happen pretty much instantaneously at the hardware unit. Why use these rather than the standalone controller? Well, for the obvious reason that they will give you complete recall of the 4Pre’s settings within your ProTools session. What the plug-in doesn’t offer is the superbly bright VU metering as found on the 4Pre’s front panel, but it does have a peak meter display. Also it’s a piece of cake to go through the preamp emulation settings and save ProTools presets depicting more descriptive names. If you’re in the fortunate position of owning a 4Pre and work in ProTools (LE or HD), grab the plug-ins and enjoy the freedom of recall.

BEYOND PRE’S

Another interesting derivation of the original Liquid Channel is Focusrite’s Liquid Mix DSP system. The Liquid Mix is a Firewire-based system that uses the same convolution technology, but in this case, to emulate classic compressor and equalisation hardware. I’ve not had the pleasure of using the Liquid Mix or Liquid Mix 16 (the 16 is a cut down version of the Liquid Mix offering 16 channels of DSP rather than the Liquid Mix’s 32) but after seeing the TDM plug-in version I now understand what all the fuss is about.

The Liquid Mix HD TDM plug-ins employ the same regime of convolution-based DSP, only in this incarnation the plug-ins utilise Digidesign DSP and can only be accessed by ProTools HD systems. The startling feature of the system is that, with a ProTools HD3 rig, you can ostensibly arc up around 100 instances of Liquid Mix tomfoolery. What’s especially nice about these plug-ins is their minuscule affect on latency. Unlike the Firewire-based Liquid Mix and Liquid Mix 16, Liquid Mix HD doesn’t incur a massive latency penalty (DSP systems for ‘Native’-based DAWs typically suffer a delay of 2048 samples). A paltry 12 samples is all the HD versions will place between the audio source and your virtual record head, meaning you can also use the Liquid Mix HD plug-ins when tracking. Fantastic.

Like the Firewire Liquid Mix, the HD versions present the same set of 40 compressors and 20 EQ units, with the single plug-in incorporating both an EQ and a dynamics section. In use, you choose a compressor and your EQ, with only that combination able to be saved as a ProTools plug-in preset. In some ways it’s a shame there’s no ability to call up a compressor or EQ plug-in individually. At least then you could save a collection of presets with names that actually represent the units being emulated. As it is I’ve gone through the Focusrite website and made up a text document outlining what exactly each emulation represents – I felt like I was looking at a delay timing sheet from about 15 years ago. A royal pain, but such are the legalities when emulating such a vast array of hardware devices. (Email me if you’re after a copy of the text – shhhh).

ProTools plays very well with the Liquid Mix HD system, with automation and recall functioning as expected – things weren’t so glitch-free in Logic Pro (v8) however, with a few graphics bugs and plug-ins seemingly forgetting how they were set up after a project was reloaded. This foible was worked around by simply saving each instance as a preset, but it was a hassle – hopefully this is on the drawing board for repair in the next update.

There’s also complete support for Digidesign’s range of control surfaces, so if you’re the owner of one of these you’ll be good to go. The plugs are also happy to be controlled via Novation’s Automap controllers.

FLUID & SEAMLESS

I’m quite chuffed with Focusrite’s Liquid Mix technology. The sound of these plug-ins represents a solid alternative to the hardware versions. Of course, nothing quite sounds like the real deal, but then, on the other side of the coin, nothing will recall or automate like plug-ins. For me, the Liquid Mix HD plug-ins represent a viable option to systems such as UAD cards, Duende, and the TC Electronic Powercore systems. The reason for this is two-fold: they’re far cheaper to buy and, perhaps more importantly, the latency ‘cost’ is far lower too. It’s a winning formula, but don’t just take my word for it; 14-day demos are available online, so check them out. Hopefully next issue we’ll be getting a look at Focusrite’s most recent audio interface: the Liquid Saffire 56, which harbours two channels of Liquid Pre technology and looks to be an interface to be reckoned with. Stay tuned.