The Liquid Channel transports classic front-end processing into the digital age, removing the need for endless patching and adding fluidity and reliability to the studio environment. Quite simply, The Liquid Channel is every mic-pre and compressor combination in history, inside a single 192kHz 2U device.

This is achieved through a unique two-part process. Firstly, the use of dynamic convolution techniques is applied, utilising lightening fast SHARC chips applying unique level-dependant impulse responses to every sample of audio. However, whilst this is more than sufficient to identically re-synthesise a compressor's sonic behaviour, in order to replicate precisely every subtle nuance, the pre-amplifier must physically match the way in which the classic unit interacts with a given microphone. The Liquid Channel's solution to this problem lies in its vast analogue front-end. A pre-amp with the ability to change its impedance and vary its signal path to either transformer or electronic, perfectly replicating the interaction characteristics of the original, whilst remaining entirely transparent within the signal path.
The Liquid Channel can therefore replicate precisely the sound of any classic mic-pre and compressor. With entirely digital front panel controls, all parameters can be saved in one of ninety-nine User Memories, meaning that entire session set-ups can all be recalled at the touch of a button. A brand new digital EQ is also available, providing a comprehensive and truly "liquid" channel strip.

A USB connection on the rear panel links to a software application enabling the archiving of both replicas and surplus User Memories, as well as providing remote operation of the unit itself. The Liquid Channel comes complete with forty classic mic-pre's and forty classic compressors but is infinitely expandable, since the USB port also facilitates downloads of further replicas from a dedicated website; www.ffliquid.com.

Finally, to account for variances in amounts of second order harmonic distortion (usually perceived as warmth) from one pre-amp to the next, a dial is included to permit control over this value. This essential feature ensures hardcore vintage enthusiasts are satisfied, bringing total control over every sonic attribute.
Essentially, The Liquid Channel provides an unlimited supply of vintage sonic performance for the price of one unit, with all the added benefits of digital processing and control.

Liquid Technology is the final product of two years pure research into what makes an analogue box sound exactly the way it does. The results of this research have enabled us to develop a hybrid system of analogue and digital technology, capable of recreating every sonic attribute of any classic processor. Focusrite has a history of manufacturing high performance equipment, and of making that technology affordable to all those at every level of the recording industry. The Liquid Channel goes further and makes the obsolete, the priceless and the historically significant, available to everybody for the first time.

Robert Jenkins - Director of Product Strategy - Focusrite.

* IMPORTANT INFORMATION: FOCUSRITE, the FF logo, LIQUID TECHNOLOGY, LIQUID CONTROL and the LIQUID logo are trademarks of Focusrite Audio Engineering Ltd. DYNAMIC CONVOLUTION is a trademark of Sintefex Ltd. All other product names, trademarks, or trade names are the names of their respective owners, which are in no way associated, connected nor affiliated with Focusrite or its LIQUID CHANNEL product and which have not endorsed Focusrite's LIQUID CHANNEL product. These other product names, trademarks, and trade names are used solely to identify and describe the third party products the sonic behaviour of which was studied for the LIQUID CHANNEL product, and to accurately describe the functionality of the LIQUID CHANNEL product. The LIQUID CHANNEL product is an independently engineered technology which utilises the patented process of Dynamic Convolution to actually measure examples of the sonic impact of original analogue products upon an audio stream, so as to electronically emulate the performance of the original product studied. The result of this process is subjective and may not be perceived by a user as producing the same effects as the original products studied.

40 Classic Mic Pres and 40 Vintage Compressors!
The Focusrite Liquid Channel is a revolutionary professional channel strip that can precisely replicate virtually any classic mic-pre and compressor ever made! Combining radical new analog pre-amp technology with special Dynamic Convolution techniques, the Liquid Channel fuses cutting-edge analog design with lightning fast SHARC DSP. Augmented by fully digital controls and optional remote software, The Liquid Channel provides the ultimate fluid vintage collection.

Focusrite Liquid Channel at a Glance:

• Replicates behavior of vintage units for authentic sound
  
• True analog preamp stages with both transformer and electronic impedance matching
  
• Special harmonic distortion control lets you match your favorite preamp
  
• Digital processing with 192kHz sample rate ability
  
• Expansion and remote control options

Liquid technology for accurate sound replication
Rather than creating a similar sound to vintage units, as with modelling devices, The Liquid Channel precisely replicates their sonic behavior. This is achieved through Dynamic Convolution - the application of a unique, level-dependant set of responses to an audio signal. These measured responses, sampled at numerous levels and with every possible setting combination, are applied to the input stream on a sample-by-sample basis for accurate replication.

Liquid pre-amplification
Mic-pre replication can't be achieved with software alone. Hardware is required in addition to account for the physical interaction with the microphone. As a result, Focusrite invested vast amounts of time and energy into designing and building the ultimate 'liquid' preamplifier, able to match the input impedance and signal path (transformer or electronic) of the device being replicated.

Not all vintage units are born equal
Second order harmonic distortion is a beneficial artifact of analog circuits (especially tube and transformer-coupled designs) providing the much-loved "warmth." However, often two units of the same type will vary in the amount of second order distortion produced, so an additional control for modifying this vintage property is provided. This allows for precise matching of the Liquid Channel to your own beloved mic-pre.

The best of both worlds - analog and digital
The Liquid Channel combines a highly complex, massively flexible analog front-end with Dynamic Convolution processing, which utilizes lightning-fast SHARC chips and runs at sample rates of up to 192kHz. The front panel controls are digital, with tactile rotary encoders; all parameters can be stored in one of 99 program memories. At the press of button, you can reload all mic-pre, compressor and EQ settings for an individual session. If using the Liquid Channel in conjunction with a recording platform (e.g. Pro Tools), both the session files and The Liquid Channel's program memory can be sent via standard data transfer methods, providing a completely mobile recording session. Perfectly replicated vintage classics with the power and ease of use of the digital domain.

Infinite expansion and remote control
The USB port on the rear panel allows remote control of The Liquid Channel, leaving the processor safely racked away. But that's not all. The software application also serves as an archiving system for additional replicas and program memories, and permits downloads of additional classic units from www.ffliquid.com. So, the Liquid Channel is infinitely expandable.


Focusrite Liquid Channel Features:

• Digital convertor with 44.1, 48, 88.2, 96, 176.4 and 192kHz sample rates
  
• 24-bit resolution
  
• 120 dB signal-to-noise ratio measured with 20 Hz/22 kHz bandpass A-weighted filter
  
• Frequency response 0.05 dB between 20Hz - 20kHz
  
• Maximum input level +22 dBu
  
• Total Harmonic Distortion + Noise 0.00035% (-109 dB)
  
• Dynamic range 116 dB measured with 20 Hz/22 kHz bandpass A-weighted filter
  
• Extremely low jitter - internal clock: <20 pico-seconds, AES digital output: <200 pico-seconds, external clock: <1 nano-second
  
• Mic preamps with gain range +6 dB to +80 dB, switched in 1 dB steps
  
• Frequency response is variable, set by pre-amp chosen
  
• Mic noise: EIN = -126 dB measured at 80 dB of gain with 150 ohm source impedance and 20 Hz/22 kHz bandpass filter
  
• Noise at analog out: -92 dBu measured at +6 dB gain with 20 Hz/22 kHz bandpass
  
• A-weighted filter
  
• Noise at AES digital out: -119 dBfs measured at + 6dB gain with 20 Hz/22 kHz bandpass A-weighted filter
  
• Maximum input level: +16 dBu
  
• Line input with gain range -10 dB to +10 dB, switched in 1 dB steps
  
• High pass filter with roll off frequency switchable between 75 Hz and 120 Hz, frequency measured at -6 dB down point, 12 dB per octave roll-off
  
• Harmonics with controllable distortion range: 0 to 15 where 15 (maximum) = 10% of 2nd-, 20% of 3rd- and 10% of 5th-order at 0dBfs (level-dependent distortion)
  
• Compressor: in "As Original" mode the parameter ranges will be the same as on the original unit being replicated. In "Free" mode the parameter ranges are: Threshold range: -40 db to 20 dB switched in 1 dB steps; Ratio range: 1:1 to limit; Attack range: 0.1 mS to 2.5 S; Release range: 0.1 mS to 2.5 S
  
• Make-up gain: -20 dB to +20 dB switched in 0.5dB steps
  
• High Shelf, Mid Band and Low Shelf EQ

Specifications Converter performance Sample rate: 44.1, 48, 88.2, 96, 176.4 and 192kHz Bit depth: 24-bit ADC SNR: 120dB measured with 20Hz/22kHz bandpass A-weighted filter Frequency response: 0.05dB between 20Hz ? 22 kHz Maximum input level: +22dBu THD+N: 0.00035% (-109dB) DAC Dynamic range: 116dB measured with 20Hz/22kHz bandpass A-weighted filter Frequency response: 0.05dB between 20Hz / 22kHz Maximum output level: +22dBu THD+N: 0.0007% (-103dB) Jitter Internal clock: < 20 pico-seconds AES digital output: < 200 pico-seconds External clock: < 1 nano-second Analogue and digital path Mic pre Gain range: +6dB to +80dB, switched in 1dB steps Frequency response: variable, set by pre-amp chosen THD+N at analogue out: 0.001% measured with a +4dBu 1kHz input signal with 20Hz/22kHz bandpass filter THD+N at AES digital out: 0.0005% measured with a +4dBu 1kHz input signal with 20Hz/22kHz bandpass filter Mic noise: EIN = -126dB measured at 80dB of gain with 150 Ohm source impedance and 20Hz/22kHz bandpass filter Noise at analogue out: -92dBu measured at +6dB gain with 20Hz/22kHz bandpass A-weighted filter Noise at AES digital out: -119dBFS measured at + 6dB gain with 20Hz/22kHz bandpass A-weighted filter Maximum input level: +16dBu Input impedance: variable, set by preamp chosen CMRR: Transformer: 123dB @ 60dB of gain Electronic: 102dB @ 60dB of gain Line input Gain range: 10dB to +10dB, switched in 1dB steps Frequency response: 0dB 0.1dB between 20Hz and 20kHz THD+N at analogue out: 0.001% measured with a +18dBu 1kHz input signal with 20Hz/22kHz bandpass filter THD+N at AES digital out: 0.0004% measured with a +18dBu 1kHz input signal with 20Hz/22kHz bandpass filter Noise at analogue out: -92dBu measured at 0dB gain with 20Hz/22kHz bandpass A-weighted filter Noise at AES digital out: -120dBfs measured at 0dB gain with 20Hz/22kHz bandpass A-weighted filter Maximum input level: +22dBu High pass filter Roll off frequency: switchable between 75Hz and 120Hz, frequency measured at 6dB down point, 12dB per octave roll-off Harmonics Distortion range: 0 to 15 where 15 (maximum) = 10% of 2nd-, 20% of 3rd- and 10% of 5th-order at 0dBFS (level-dependent distortion) Compressor In 'As Original' mode the parameter ranges will be the same as on the original unit being emulated. In 'Free' mode the parameter ranges are as follows: Threshold range: -40dB to 20dB switched in 1dB steps Ratio range: 1:1 to limit Attack range: 0.1ms to 2.5s Release range: 0.1ms to 2.5s Make-up gain: -20dB to +20dB switched in 0.5dB steps EQ High Shelf Frequency range: 200Hz to 20kHz Gain: +/-18dB Mid Band Frequency range: 100Hz to 10kHz Gain: +/-18dB Q: variable between 0.8 and 2.5 Low Shelf Frequency range: 10Hz to 1kHz Gain: +/-18dB Weight 8.6kg 19Ibs Dimensions 484mm (W) x 85mm (H) x 270mm (D) 19" (W) x 3.5" (H) x 10.6" (D) 2U rackmount * IMPORTANT INFORMATION: FOCUSRITE, the FF logo, LIQUID TECHNOLOGY, LIQUID CONTROL and the LIQUID logo are trademarks of Focusrite Audio Engineering Ltd. DYNAMIC CONVOLUTION is a trademark of Sintefex Ltd. All other product names, trademarks, or trade names are the names of their respective owners, which are in no way associated, connected nor affiliated with Focusrite or its LIQUID CHANNEL product and which have not endorsed Focusrite's LIQUID CHANNEL product. These other product names, trademarks, and trade names are used solely to identify and describe the third party products the sonic behaviour of which was studied for the LIQUID CHANNEL product, and to accurately describe the functionality of the LIQUID CHANNEL product. The LIQUID CHANNEL product is an independently engineered technology which utilises the patented process of Dynamic Convolution to actually measure examples of the sonic impact of original analogue products upon an audio stream, so as to electronically emulate the performance of the original product studied. The result of this process is subjective and may not be perceived by a user as producing the same effects as the original products studied.

Here follow some initial frequently asked questions and answers. For a growing number of up-to-date support articles relating to this product, we highly recommend you visit the Focusrite Answerbase.

Q: What kind of technology is used by Focusrite in the new Liquid Channel product?
A: The technology involves dynamic convolution techniques and a new liquid pre-amp which together emulate vintage pre-amps and compressors.

Q: What is Dynamic Convolution?
A: The Convolution process has been defined as: 'The term given to the mathematical technique for determining a system output, given an input signal and a system impulse response.' What that means is if you know what is coming in to your system, and you can control your system?s impulse response, you can define the system's output. In other words, you can emulate a compressor's sound, (or even a mic-pre's sound if you add a suitable analogue mic-pre hardware circuit.) Put another way, Focusrite have found a way to accurately emulate the way in which any classic compressor or mic-pre ever made affects sound.

Q: How is this different from modelling and other 'simulations' we've seen and heard before?
A: Modelling looks at the way a device works and then relies on the generation of code to try to emulate the typical way in which a device would respond, usually in a certain limited set of situations. Convolution, on the other hand, records data about the way a device behaves and then emulates that. To use a simple analogy, it's like the difference between sampling and synthesis; if you want a REAL violin sound triggered from your keyboard you sample a violin, if you want a modelled sound which recalls the real sound of a violin, synthesis will generate a similar violin-like waveform.

Q: So why have modelling devices never succeeded in nailing the way a compressor or mic-pre responds?
A: The problem with a compressor is that it is a dynamic processor. That is, it is reacting to changes in input signal, and varies its response according to those changes. The problem with a mic-pre is similar- it is constantly interacting with whichever microphone is feeding signal to the pre, and it is the combination of pre and mic that characterises the sound. Dynamic convolution plus liquid hardware enable these phenomenally complex interactive relationships to be emulated.

Q: So what does the impulse response/convolution process involve?
A: A while back, Focusrite set about driving a huge set of impulse responses into the best collection of vintage and modern compressors and EQ's ever assembled. The impulse response device they used for this process is called, with good reason, 'The Replicator'. This mysterious black box outputs an impulse (a very narrow (time-wise) voltage spike of amplitude which contains an infinite number of frequencies.) The impulse spike is sent to the device you wish to emulate. By measuring the output of the device itself, Focusrite's R and D team were then able to calculate what the device has done to the spike, hence calculate the aspects of the device that relate to frequency- and time-related parameters; frequency response, distortion.

Q: So The Liquid Channel can emulate the sound of any compressor and any mic-pre ever made? I pay once and get the sound of all my dream processors in a 2U rack space?!
A: Yes, and more. Once you have The Liquid Channel you can mix and match the sound of your dream pre's and compressors into user memories to set up and recall any combination you want.

Q: That's science fiction!
A: It was science fiction, now it's science fact. Welcome to a new world of endless possibilities

Q: How on earth can one machine deal with the sheer weight of calculations required to produce ALL those responses for every group of parameter settings of ALL those mic-pre's AND compressors?
A: Good question. It took the world's fastest audio-implemented SHARC chip technology to be able to crunch the mind-boggling numbers. That, and a huge number of patient hours emulating the sound of the classic units from audio history.

Q: So everything is pre-programmed?
A: No, all the convolution programming has already been done for you, but of course the impulse responses have to process the audio in real time inside The Liquid Channel.

Q: Does The Liquid Channel allow me to emulate my own choices of pre and compressor
A: No, that's pretty specialised stuff and best left to the Focusrite R and D team, but the unit ships with a huge range of pre's and compressors ready to go in the box. You can make up your own combinations and store them in user memories, with or without EQ:

Q: How many compressors and mic-pre's do I get in one unit?
A: The unit ships with emulations of 40 of the classic mic-pre's from history, as well as emulations of 40 of the world's finest compressors.

Q: Are there user memories in addition to these?
A: Yes, the mic-pre and compressor 'building blocks' can be combined into 100 user memories; all parameters including mic-pre gain, EQ and compressor settings etc are also stored within the user memory of course.

Q: What if I want the sound of a specific mic-pre or compressor, which isn't one of the chosen devices?
A: Focusrite plan to make the sound of further pre's and compressors available as downloads from this website. A free piece of application software will be available that will allow you to download extra pre?s and compressors via the web to your PC or Mac. You can then load the sound of the pre?s and compressors that you crave into The Liquid Channel via the USB port on the rear panel (fitted as standard.) You can also save user memories and/or mic-pre and compressor emulations externally to your PC or Mac, and even edit the unit remotely via USB! All parameters will be editable on-screen remotely, even mic-pre gain settings for example, and can be transferred from session to session in e.g. a Pro Tools folder.

Q: What if I should overwrite my classic compressor by mistake?
A: No problem; you can always reload a back-up set from your PC or Mac, or download the original factory settings from www.ffliquid.com

Q: How can convolution emulate the interaction of mic-pre and microphone?
A: On its own it can't. You need a separate analogue circuit to be present and to work with the convolution engine.

Q: So why do mic-pre's present such a problem?
A: Mic-pre's have always had to connect to the source microphone, but it's an interactive system that isn't 100% efficient. Mic. amps have been designed since 1920's to suit a wide variety of different types of mics.- passive carbon dynamics, then coil-based designs, then valve amplifiers, large diaphragms, phantom powered condensers etc. Hence, different vintages and types of mic. amp, will vary dramatically in terms of the way that their input has been designed. For example, the range of electronic/transformer front ends that have been used over the years exhibit a wide-ranging set of impedances, and this is why an analogue front end needs to be included. If a specific mic. is not being loaded by the analogue circuit just as it was by an original vintage device, then the sound from that microphone will be different.

Q: So there's no real mic-pre standard?
A: Exactly. Take a transformer for instance. It has two coils of wire, the 1st coil generates a magnetic field, and this then passes into the 2nd coil- which in itself is not a fixed transfer mechanism, there?s a lot of variation in transformers. What impedance appears at the input of the pre is also a key factor- when you connect a mic. it has an output impedance of its own. The two sides (mic. and pre) react, and frequency-related level can vary wildly as a result. Capacitances also interact as both mic and transformer have capacitances that vary, so HF roll off may occur for example, or you may get an HF peak (The famous Focusrite ?airiness? typified by the ISA range for example,) Older mics. designed for broadcast applications often roll off at e.g. 12kHz, since before 1970 few people cared about HF matters. (Designers used to just roll off at c12kHz to filter out problems above this threshold.)

Q: So how do you design one mic-pre circuit that can reproduce all the variables within this wide range?
A: The only way to accommodate the full range of different designs is to allow huge flexibility in the resistance and capacitance parameters in a custom transformer designed specifically for that flexibility. Hence, The Liquid Channel physically changes analogue circuitry as well as using dynamic convolution technology to create mic-pre emulations.

Q: What about electronic or tube mic pres that do not include a transformer?
A: The Liquid Channel's transformer is auto-switched out when an electronic transformerless mic-pre is chosen by the user (this is indicated on the front panel). Focusrite has built in the variations required to reproduce the vagaries of a range of electronic mic-pres. The capacitance and resistance are then varied in the circuit, and Dynamic Convolution technology is used to emulate the full range of electronic pre's. Tube emulation is also covered 100% - this is taken care of by the Dynamic Convolution process. Whatever artefacts were present in a classic vintage tube piece are also present in The Liquid Channel.

Q: So this is really a hybrid technology that allows total control over the key aspects of the sound of analogue pres and compressors?
A: Yes, the sound of every opto, and every VCA compressor, every transformer-balanced, electronically balanced (including tube pre's) can be emulated, because each device's response has been calculated.

Q: Why is it necessary to have additional circuitry for the mic-pre and not the compressor. Surely, if the convolution DSP is as thorough as you say, there should be no need for further processing
A: As mentioned above, the interaction between the individual microphone and pre-amp, is a key factor in the sound of the pre as a whole. (The ISA 428 and 430 MK II have switchable impedance values that the user can implement to specifically tailor the character and response of the device for this very reason.) By including a 'Liquid' pre-amp circuit containing a flexible signal path (transformer or electronic) and variable impedance value, The Liquid Channel can mimic that of the classic mic-pre to ensure that the interaction with the microphone is close to the original. This issue isn't something that affects a compressor but the DSP processing required is nonetheless immense. The user's ability to affect the threshold and ratio of the compressor means that there are additional responses needed for the side-chain to account for the numerous variations in character (types of 'knee', presence of 'over-compression' etc.)

Q: Is the transformer the traditional Focusrite Lundahl transformer. Or another famous brand like a Jensen, should be no need for further processing?
A: No, it's a brand new custom precision-wound FF 'Liquid' transformer, designed and built in the UK by Focusrite's R and D department to be extremely flexible; transparent or coloured as required. But remember, you don't have to think in terms of the sound of just one classic transformer or mic-pre design. Now you can have them all?

Q: Other products like the Focusrite ISA 428 allow you to vary the impedance. Is the mic pre in The Liquid Channel doing the same thing?
A: Yes, but with traditional products your choices are pre-defined, and generally speaking relate only to impedance. With The Liquid Channel all aspects of a mic-pre's performance are being emulated.

Q: If I connect different mics to the plethora of mic-pres that The Liquid Channel offers, will each of the mics sound different?
A: If I connect different mics to the plethora of mic-pres that The Liquid Channel offers, will each of the mics sound different?

Q: What about interaction between the mic-pre's and compressors
A: The Liquid Channel's dynamic convolution DSP is separate for both the pre-amp and compressor. That is to say, the device acts exactly as the separate units would, with the same signal leaving the mic-pre and entering the compressor. So, interaction is identical to the hardware equivalent without the extra cost/size and weight/plugging in required but with all the reliability of a first class digital audio device.

Q: What about EQ?
A: Focusrite's R and D department in England decided that a truly liquid channel strip should also include a flexible EQ: So they created a brand new digital EQ, modelled on the curves of the fabled ISA110. This EQ is a single Focusrite British EQ design that is the perfect complement to the range of mic-pre?s and compressors available.

Q: Will the EQ sound exactly like an ISA 110's EQ
A: It's based around the 110 design, but since it doesn't use convolution technology it won?t be exactly the same. If you want the original sound of a Focusrite EQ unit with the same classic analogue footprint as the Focusrite's of the 1980's, buy an ISA430 Mk II or an ISA220.

Q: Why is there no tube? If the transformer is required in the analogue circuit how come a tube is not also required?
A: The dynamic convolution process handles the tube characteristics. However, there are additional benefits to using transformers over and above their warmth; better CMRR and the transformer's direct impact on the connected mic. directly for example. This latter point is why we need a transformer in circuit to emulate the mic-pre- the interactivity with the mic. is key for a transformer in a way in which it is not key for a tube.

Q: Are there any audible (distortion) differences between applying an 'HG' emulation versus using a regular level emulation and then adding 2nd/3rd/5th order distortion via the dedicated encoder afterwards?
A: Yes. At full gain on an old mic-pre. you may have 60dB of gain at 1k but only 40dB at 10k. Distortion is affected in a similar way. 3rd order harmonic distortion is reduced at low gain, so this may be present when using an HG emulation, but not present if you just add 2nd order distortion after the fact. This is one reason why we include HG settings.
There are also differences re: different loadings on the transformer occurring when driving high gain in at the front end, hence mic. interaction changes occur. For example, HF roll-off etc may change.

Q: Why do we only use one set of impulses when creating the emulations? Surely we need to emulate all combinations of threshold, ratio parameters etc?
A: Dynamic convolution, using a single set of impulses, accurately emulates the sound of the signal path at all frequencies/levels. However, the FF Liquid process is actually more complicated than this.
After emulating using convolution, we then measure the compressor curve at different ratio/threshold positions. Then we measure the attack and release characteristics, as well as the RMS vs. Peak detection of the side-chain signal in order to see if it discriminating more towards peak or RMS. (If you put e.g. a drum kit thru a peak-detecting compressor such as a Focusrite) the compressor side-chain will follow the curve of the signal that's coming in and compress in a manner that follows that curve. An RMS compressor will compress the signal against the average level and ignore the peaks. Hence a drum kit is smoothly compressed by an FF piece, but an RMS unit will result in attacky/toppy compression with many transients which have more energy/are less smoothly compressed.

Q: Can you route the digital input into the mic-pre's?
A: Yes, you can route the digital input to any of the the mic-pre's, or only via the transformer, or directly to the compressor in the digital domain.