A complete, modular, expandable Recording & Mixing Console with 4 boutique mic preamps, world-class converters, a studio full of outboard gear and a professional Atmos capable analog monitor controller.

Integrated with a future-proof computer interface.

ULN8 mkIV BackPanel
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Heavenly Metric Halo Sound

mk IV Analog, Preamps & Conversion

For over 20 years, Metric Halo sound has been beloved by musicians and audio engineers the world over.

Our 4th generation mkIV analog and converter stages enhance the already world-class design of the LIO-8/4p to provide you with warm yet detailed, open & musical sound that captures and presents your work in its best light.


Analog + Atmos + Processing

The mkIV features a full featured multi-source, multi-destination surround capable (up to 7.1.4 Dolby Atmos®) monitor controller with analog gain control and relay hard mutes.


128 Channels | 64 Buses | 192k

Imagine having a large-format recording and mixing console in a 1RU unit. mkIV is just that — you will not be limited by this mixer.


Network Audio Backplane

MHLink provides an ultra-low-latency, ultra-high-bandwidth self configuring audio and data backplane between multiple MH units as well as a native Gigabit Ethernet interface to the computer.


Driverless Class Audio

Every mkIV unit includes a USB Class Audio interface that allows you to connect to any USB Audio host (Mac, iPhone, iPad, Android, Windows 10+, or Linux) without having to install a driver.


USB I/O Sidecar

In an MHLink system, the USB port on each mkIV unit provides our unique “Satellite Computer Port (SCP)” capability.

SCP gives you the ability to patch a satellite computer with full routing into the mkIV Mixer. On multiple unit systems, all SCP ports are available simultaneously.

Integrate software instruments, sample players, client computers and mobile devices into your system without the need for additional interfaces or complicated clocking setups.


Flexible Re-routing

Any channel in the MIO Mixer can be routed to any output, including outputs sent back to the host or to an SCP port.

Route audio between apps or computers without any additional software or an additional complex routing model.

Signal Processing

FPGA/DSP Hybrid Engine

mkIV features our custom hybrid DSP/FPGA processing system that provides massive amounts of processing and gobs of memory for high-precision fixed point mixing, cross-point interpolation, metering and routing as well as flexible, instantiable floating-point plug-in processing.


Zero-Latency DSP

mkIV bundles over a 100 zero-latency hardware plug-ins, including the entire Metric Halo Production Bundle and the +DSP Bundle, with no additional license fees or complicated licensing tools.

That’s over $2800 worth of world-class plug-ins bundled for use on the LIO-8/4p mkIV DSP for free!

Control Surface

Mackie | EuCon | iPad | Tablet

mk IV supports a variety of control surfaces giving you tactile remote control over mix, monitor, and recording.


Expansion I/O HW Plug-ins

Each mkIV unit includes an open EdgeBus Card slot. The EdgeBus Card slot allows you to expand your system with additional I/O without having to add a new interface.

Boot States

Standalone Operation

mk IV allows you to store the full configuration of your multibox MHLink system into non-volatile memory so that the full configuration is automatically restored when the system powers on - without requiring a connection to the computer or MIOConsole.

Format Conversion

Digital and Analog Conversion

Crosspoint routing and all I/O ports simultaneously active enables you to use the mkIV as a flexible format converter. Boot states allow you to program and set the unit for standalone format conversion


Integrated Tracking DAW

mkIV includes complete tracking DAW that supports Live, Take-based and Overdub recording workflows. Always available and completely integrated with the hardware. It launches instantly as part of MIO Console and it doesn't require any licenses or dongles.


LIO-8/4p mkIV Key Hardware Features

Whether you are on location, in the studio or the mastering room, the LIO-8/4p mkIV has what it takes for you to get the job done.

LIO-8/3p mkIV is built on Metric Halo’s core 3d Technology, so it interoperates seamlessly with all existing MH 3d interfaces.

Since it is amazingly flexible, expandable and future-proof by design, your system always scales to meet your needs. Each unit includes these hardware features:

The mkIV excels in these key areas:

• Tracking
• Mixing
• Mastering
• Live
• Monitors
• Production
• Remote Mic Pre
• A/D/A
• Active Analog Split
• Digital Snake
• DSP Processing
• Format Conversion
• Headphone Amp
• DI
• Meter Bridge
• Monitor Control
• Cue Playback
• Session
• IR Remote
• Tactile Control
• Wireless Control

Integration for the Win

By implementing all the functions of a complete end-to-end signal chain solution in a single package, the LIO-8/4p mkIV is able to provide unprecedented capability and quality in a lightweight, low-power, single rack space unit. This integration has significant benefits in the form of reduced setup time and greater reliability, reduced cabling, weight, power consumption and cost, even as it provides unprecedented flexibility and performance.

The MHLink routing and transport architecture allows you to build a system with units distributed up to 100 meters apart with no added latency.

MHLink's auto-configuration and hardware aggregation make it so the entire system appears to the host computer as a single unified interface. Audio, command and clock transport with up to 256 channels of audio (at 192k) is accomplished with light-weight, inexpensive, readily available Cat 5e cabling.

The new mkIV design is eco-friendly and uses very little energy to provide its incredible performance and power. Even when every mic channel is powering a 48v phantom mic, the LIO-8/4p mkIV only consumes 25 watts, and without phantom uses less than 21 watts.

This low-power design allows the mkIV to run cool and stable. No noisy fans required.

Metric Halo Sound

The sound of an audio product is more than the the sum of its parts. You can’t simply look at the components used and determine how something is going to sound. Excellent audio requires careful attention to detail and the tuning of every element of the entire system; this includes the analog stages, the power system, the clock and the converter itself. As all of these interact with each other in nonlinear ways, it is the system that determines the performance, and not any of the individual parts.

The A/D/A converters in the LIO-8/4p mkIV are DC-coupled to the analog I/O stages so they introduce extremely low phase distortion. The D/A has no low-frequency filtering. The A/D converters have an extremely low frequency DC blocking filter that calibrates the input path and removes DC offset with minimal phase shift.

Every element of the design combines to give you a warm, open 3-dimensional sound that is highly revealing and yet totally natural. Metric Halo mkIV sets a new standard.

It’s digital with soul.

Green Room Studio, Vienna Austria


The LIO-8/4p mkIV includes 4 channels of Metric Halo’s renowned ULN-R preamps (with space to optionally add another 4 at any time you desire). These boutique preamps are famous for their pristine, low-distortion, completely unveiled sound.

The ULN-R preamp provides up to 90 dB of digitally-controlled analog gain in precisely recallable 0.5 dB steps. Each input supports independently switchable P48 phantom power.

The combination of the super transparent ULN-R preamp and Metric Halo’s exclusive insertable Character Component Modeling Processing provides flexibility and sound quality that’s unavailable on any other device. You can transition from a wire-with-gain pre to a gooey tube pre or anything in between; every input can have the right Character for the sound you want.

The preamp input path on the LIO-8/4p mkIV always has preamp gain control and has DC blocking for the phantom power, it also supports input levels of up to +20dBu with no fidelity reducing pads, so you can handle high SPL with sensitive mics as well as you can handle extremely low SPL with insensitive mics (like ribbon mics and low output dynamics) while maintaining ultra-low noise.

The high maximum input level of +20dBu also means that you can use the mic pre input path as an alternative line input path. This feature can be used with the monitor controller to access an additional 8 selectable analog inputs as external sources.

The LIO-8/4p mkIV input path features an integrated analog send (pre A/D converter) which allows the unit to be used as remote controlled analog preamp. MHLink connectivity and control means that your preamps can be really remote (up to 100m away from your control interface) when you need them to be.

The preamps also offer a send/return mode where the amplified signal from the preamp is sent to the analog send and the line input is used for the return to the A/D converter - this allows you to patch analog processing between the preamp and the converter. Finally, you can use the analog send to provide the pre-amplified signal to a backup recording or mixing system; this is a fully analog split that represents a true backup signal with no digital dependencies.

Paper Street Audio Company


Monitoring is critical to the production process at every stage; you need to be able hear exactly what you are working on. Your monitor chain will be limited by the weakest link in the chain. The LIO-8/4p mkIV integrates a transparent digitally controlled analog monitor controller to ensure that you can connect directly to your reproduction chain without having to reduce the fidelity of your signal with an inferior monitor control system.

mkIV hardware includes a relay driven shunt mute circuit on all the analog outputs that prevents transients from getting into your power amps and speakers. The mute is designed to be completely out of the circuit under normal monitoring operations. It automatically protects your monitors during power cycles and sample rate changes.

The Monitor Controller in the LIO-8/4p mkIV provides sophisticated monitor control features that are only available in dedicated monitor controllers that surprisingly cost more than the LIO-8/4p mkIV.

These features include:

In addition to all these high-end features, the MH Monitor Controller provides unique support for per-output-path configurable signal processing including EQ, Bass Management and protective limiting. Each output path can have its own signal processing, even if the paths share speakers. This allows you to configure alternate monitoring setups with one monitoring system (for example, you could configure the signal processing to provide a band-limited monitoring path or a path that lacks subwoofer reinforcement).

Each LIO-8/4p mkIV includes a high quality headphone amplifier with dedicated D/A conversion (which is the same quality as the primary D/As in the system), and digitally controlled analog gain control. So you don’t need to add a headphone amp to your system. By default the headphones are configured as a parallel Cue output multed from the Monitor Controller, but you can drive the headphones with an independent mix or you can make them an alternate output for the monitor controller.

Paper Street Audio Company

Cue Control

In addition to monitoring the mix in your control room, multitrack production requires providing multiple output cues to performers, producers and/or broadcast feeds.

The Monitor Control in 3d is enhanced by a sophisticated Output Cue section that provides you with an arbitrary number of output controls. Each cue can be driven from any of the busses in the system, or it can be set to derive its input from the currently selected source in the Monitor Controller (MC).

Since each Cue can be driven by a separate mix bus from the mixer, they are perfect for routing and controlling independent headphone mixes for individual performers.

Cues can be configured to listen to PFL/AFL (or not). So for producers and engineers, the cue can follow PFL/AFL Solo in the mixer while performer and broadcast cues are unaffected by soloing.

Each cue has an independent output path which can be set to any of the MC supported output types. Each cue controller uses the MC engine for its control of routing, gain, delay and output graph processing, so it can do all the things the MC can do.

Cues form the basis of the routing points for Talkback and Listenback.

Talkback provides the ability to route a specific input to any sub-set of the cues in the system; it also allows you to control the amount that the Cue source signal is dimmed when talkback is active. The Talkback signal is mixed with the selected source.

Listenback provides the ability to route the source that the engineer is currently monitoring through the Monitor Controller to any subset of the cues in the system. This allows playing back a mix of the take to any or all of the monitoring cues in the system without having to re-patch.

Kimleng Audio, Bangkok Thailand

Ultimate Console and Mixer Solution

For 3d and mkIV, we designed a new, retina-enabled, 64-bit, cross-platform console application: MIO Console 3d.

MIO Console features a high-impact, modern, flat design with scalable UI elements. With user controllable color theming and extensive support for user-configurable interaction preferences, it is easy to tune the console to fit your style (and your eyesight). MIO Console also adds support for standard UI gestures including drag-and-drop for inserts and multi-strip control swiping.


MIO Console provides the UI to control the mkIV Mixer. This mixing engine is a full blown mixing console - not a mere interface monitor mixer. It features multi-bus mixing, arbitrary routing, input and output multing, zero-latency hardware plug-ins, surround support, and headamp control. The Mixer removes the limits that other interfaces have by providing:

These features taken together unlock mixing workflows specifically targeting live and zero-latency cue mixing during tracking as well as enabling you to record and mix with Session as a dedicated solution.

Paper Street Audio Company

MHLink - All Together Now…

MHLink redefines audio interconnect technology.

It supports up to 128 channels at 32-bit/192k, bidirectionally, on each port.

MHLink intelligently manages low-jitter audio clock distribution, high-bandwidth audio streaming and system control data all on a single lightweight, inexpensive, industry-standard Cat5/5e Ethernet cable.

The MHLink transport automatically unifies all connected devices into one super unit — which maximizes your audio performance while minimizing complexity.

Expanding your system is as simple as chaining another unit.

MHLink devices can be added dynamically without interrupting running audio streams. All I/O ports of new devices are automatically available for routing within seconds of being connected.


MHLink key features:

Instantly Scalable

A unique feature of MHLink is that all Metric Halo interfaces work as well as a group as they do individually. Mix and match LIO-8/4p mkIV with other 3d units to create a system that meets your needs for track count and preamp power.

Adding a unit to the system automatically increases the DSP power of the system, so that your DSP always scales with your I/O.

Break your system up for small gigs when playing out or add the units of your mates to build a huge system when required - just click to connect!



Every mkIV unit includes an industry standard USB-C port that provides a device port featuring 3 interface endpoints:

The Audio Class and MIDI Class endpoints support industry standard protocols and allow the mkIV to be used with the built-in drivers of any USB host that supports the standard classes.

You can transport audio and MIDI to and from computers running macOS, Windows 10 & 11, or Linux without installing a custom driver.

You can transport audio and MIDI to and from mobile devices (and embedded devices) that don't allow the installation of custom drivers, as long as the devices provide built-in Audio and/or MIDI class support. At present iOS devices (including iPhone and iPad), Android devices (phones and tablets) and AKAI MPC have the appropriate class drivers included.

MIOConsole3d also controls the unit over USB so you can connect your computer with one cable.


Have you ever wanted to connect an iPad to your main studio system? How about dedicating an older computer you have laying around to running a VI or a Sampler? What about when a client or collaborator comes in with their laptop and wants to run audio into your system? With mkIV and SCP, you can just connect any of these devices right into your system without having to add another interface just for that purpose.

mkIV supports explicit routing to and from the USB connector on any unit in the MHLink chain. When used in this way the USB ports are referred to as Satellite Computer Ports.

This feature allows you to integrate audio from multiple USB host devices (computers, phones, tablets, MPCs, etc.) without having to purchase additional interfaces. It automatically keeps your devices synchronized with your system and provides device to device routing as well as integrated mixing and processing.

You can connect a sampler running on a another computer and directly mix its outputs with the rest of your sources. You route directly between computers/devices or mult signals to multiple computers/devices - so you can set up a computer or an iPad as an effects rack or backup recorder.

You can integrate the output of multiple iOS instruments into your MHLink Mixer via the direct digital link and you can record real-time performances by routing them to your main recording computer.

You can use the SCP functionality to integrate multiple computers (or iOS devices) into your MHLink mixing engine. Each USB port is available for connection with a USB audio host. The SCP USB source and destination categories in the routing selector popups allow you to select explicit USB channels to route to and from.

To use a USB port as an SCP port, simply connect the device to one of the USB ports on one of the units in your MHLink chain. Then on the device, select the USB interface of the connected 3d unit as the audio interface for the device, signal processing software or DAW.

It’s as simple as that.

Recording stage box for “Charlie Fox in Cuba as Carlos Zoro”, Actual Size Audio (Michael Ryan)


Have you ever wanted to route audio from one app to another? For example maybe you want to capture a reference track from a streaming service or you need to grab the output of your DAW (post analog processing) and capture it to your mastering app. Or perhaps you need to route some audio from a pro app to your teleconferencing software.

The mkIV mixer supports the computer and SCP ports as first class routing destinations which makes it easy for you to route any signal back to the computer or any of the SCP ports.

You can use this feature to route audio between apps on one computer, between different computers, or to mobile devices.

Since the routing points are built into the mixer, the signals you loop-back to the computer can be outputs from the computer, any mix, or the output of any signal processing chain.

You can use this feature to capture masters, route between your DAW and teleconferencing apps, or between standalone VIs and your DAW.

“Charlie Fox in Cuba as Carlos Zoro”, Actual Size Audio (Michael Ryan)


LIO-8/4p mkIV includes a sophisticated digital signal processing engine that is only limited by your imagination. The mixing engine and audio router built into each unit is capable of mixing 128 inputs to 64 busses at all sample rates (up to 192k) with every gain interpolated on a sample-by-sample basis. This custom dedicated mix engine utilizes the equivalent DSP power of 30 of the SHARC DSPs that were used in our previous generation product (based on the 2d Card).

Each LIO-8/4p mkIV also includes a programmable DSP that supports the instantiation of arbitrary DSP processing plug-ins; this is used for insert processing in the mixer and for output processing in the Monitor Controller. LIO-8/4p mkIV includes over 100 plugins that you can use for low-latency monitoring, live mixing or in production. The DSP in 3d has 1GB of DDR3 RAM available so long delays and multiple reverbs are not a problem.

The +DSP license included with every unit provides Metric Halo’s unique Graph insert which allows you to build your own signal chains with arbitrary phase compensated routing between plugins; think of it as a DSP playground. You can insert a Graph in any insert slot in the mixer and as output processors in the Monitor Controller.

The 3d system enhances the processing engine included in each unit by routing between multiple units and utilizing the resources of all units attached via MHLink as one unified system. Your DSP and mixing resources are pooled. This allows you to seamlessly grow your system one unit at a time - all the way up to 128 channels of simultaneous input and output! All your inputs (including inputs from the computer) are available as sources in the mixer and monitor controller. All your outputs (including returns to the computer) are available as destinations for the mixer, monitor controller, cue system and direct outs.


All the plugins below are available for instantiation on the hardware. This allows them to be used with zero latency during tracking, monitoring and live-mixing. It also makes them available for mixing recordings made with Session.

These plugins include the full feature set of the Production Bundle plugins, including things like the embedded SpectraFoo Real-time Spectrum Analyzer. The 3d versions of the Production Bundle plugins share user presets with the Native Production Bundle plugins, so presets saved with the MH Preset system are usable in all versions of the plugins for easy migration to native DAWs.

ChannelStrip UI

What do Super Mixers Jack Joseph Puig, Serban Ghenea, Billy Decker, Richard Furch and countless others choose as the indispensable channel strip processor for their mixes?

Metric Halo’s ChannelStrip of course!

“I like Metric Halo, I would die if they took that away. I’m a huge proponent of Metric Halo.

Any particular plug-in of theirs?

I like ChannelStrip. Without that, I’d actually be suicidal. Nothing does what that does.”

– Jack Joseph Puig

“I’d attempt to compare it to other similar plug-ins, but the truth is I only use ChannelStrip. To me, ChannelStrip together with Pro Tools is the console.”

– Serban Ghenea

“I once found myself in a situation without ChannelStrip, and I tried to mix anyway. It didn’t work. The mix sounded terrible, and I won’t ever try it again. ChannelStrip is absolutely indispensable to everything I do.”

– Billy Decker

“… I used to do that when I mixed on SSL consoles, but no other plug-in – not even SSL emulators – could replicate that trick quite this way and keep the gain exactly steady. ChannelStrip does.”

– Richard Furch

ChannelStrip is like having the channel strip section of a large format console - with a few awesome Metric Halo twists.

ChannelStrip integrates everything you need to process the channels that make up a mix as well as process the entire mix bus.

Featuring an Expander, Compressor, multi-band EQ, and a limiter, ChannelStrip provides a unified interface for processing your tracks. It also includes phase invert, channel delay, comprehensive metering and SpectraFoo™ spectrum analysis - so you can see your audio as well as you can hear it.

ChannelStrip is an essential tool for every project. And it is included with every mkIV.

Dirty Delay
DirtyDelay UI

MH Dirty Delay is a fantastic-sounding feedback delay processor with integrated Character and Filters in the delay path. Use it to create awesome vintage echo and tape-delay style sounds as well as create lush and subtle spaces in a mix.

Not just a musical feedback delay, MH Dirty Delay is something special. With integrated Filters and Character in the feedback path, you can make it clean or dirty, vintage or futuristic, subtle or nasty.

With dual delay lines, crossfeed, feedback and distortion control, Dirty Delay is capable of creating extraordinarily rich and complex textures and patterns from your audio. Dirty Delay adds texture and movement without the veiling and darkening of the sound that is often associated with feedback delays.

Dirty Delay is equally at home in production and performance.

Character UI

Character is a plug-in that lets you add the luscious distortion characteristics of classic analog circuits to your source tracks. To create Character we asked top flight tracking, mixing and mastering engineers to send us their favorite analog hardware; the mic pres, DIs and EQs that they used for recording, mixing and mastering. We then used SpectraFoo to measure the ways that these processors add lovely, shiny analog distortion to the sound run through them and modeled this distortion using our proprietary +DSP technology.

Character provides over 20 different models, incorporating the sound of tubes, transformers and solid state devices. Character has a Drive control (and autodrive) to allow you to push the distortion even harder for over-the-top sound mangling.

TransientControl UI

TransientControl is a plug-in that allows you to modify dynamics in ways that just aren’t possible with traditional compressors. You can directly change the transient (“attack”) and sustain of your audio; this allows you to make your tracks more punchy, or smooth them out so they sit in a mix.

TransientControl analyzes your audio and distinguishes between the onset of sounds (the attack), the sustain of sounds and the decay of sounds (the release). With three gain controls you can dial in the relative level of these three elements of the sound.

TransientControl can enhance the attacks of finger-picked guitar, or mute the attack of strumming. Use it to make an instrument sit in the mix or pop out. Control the snap of a snare without affecting the ring. Even use it to change the feel of a percussion pattern.

TransientControl does its magic in real-time with no latency, so you can use it for mixing and live.

Precision DeEsser

Precision DeEsser is a plug-in that allows you to manipulate your tracks and remove excessive high frequency content. It combines the high precision filter technology and dynamics processing of ChannelStrip with the metering and analysis of SpectraFoo to allow you to zero in on offending frequencies and correct them quickly and efficiently.

Precision DeEsser features comprehensive listening controls to allow you to hear exactly what is (or isn't) being removed. You can choose five different points in the processing chain to monitor.

The Precision DeEsser is an essential tool for vocal tracks, but can also be used for sound design and other audio processing.

Multiband Expander
Multiband Expander UI

MultibandExpander is a plug-in that allows you to manage, suppress and control noise in your tracks in a frequency-sensitive way. The 3-band phase-coherent crossover network directs the audio to three independent expanders that you configure to smoothly suppress noise below the threshold you specify. The expanders can also be configured to change the feel of rhythmic patterns by suppressing elements that are played more softly – all in a frequency-sensitive way.

Multiband Expander features SpectraFoo™ spectral analysis to allow you to zero-in on crossover points and thresholds quickly and precisely.

The Multiband feature of the expander is extremely useful for controlling noise and hum in guitar tracks.

Multiband Dynamics
Multiband Dynamics UI

MultibandDynamics is a plug-in that allows you to add clarity, warmth and punch to your mix. It shapes timbral quality of your audio by running it through a three-band crossover, and providing independent compression in each frequency range before summing the result through a limiter. Without compression, you can broadly shape the timbre of your tracks, and if you need dynamic range control or dynamic EQ, simply enable the compressor for the band.

Multiband Dynamics is an essential tool for mixing and mastering, but can also be used for sound design and other audio processing.

HaloVerb UI

HaloVerb is a plug-in that allows you to add ambience and depth to your recordings. HaloVerb for 3d expands on the original 2d-Expanded Hardware reverb to give you great algorithmic sound with more flexibility and control. Use the reverb impulse to see the reverberant field as you make adjustments, or hide the graphics and let your ears be your guide.

Add subtle ambience or generate the sound of a vintage echo chamber - the extensive presets and easy to use UI let you dial in the sound you want quickly.

Thump UI

Thump is a unique audio processor that allows you to synthesize low frequency audio to add low end to a track or generate another sound entirely. Thump looks at the pitch and dynamics of its audio input and uses this information to control its oscillators. You can add low end to drums, augment a bass or even create synthetic drones.

Thump is ideal for beefing up a kick drum, add low end to percussive tracks, re-create classic drum synth sounds, and more.

You can use Thump's envelope driven, percussive sub-harmonic synth for the following things (among others):


SuperGate is dynamics processor that specializes in isolating (or removing) instruments or audio events based on the program dynamic signature. It uses a dynamically controlled state machine to apply precision time-domain gain curves to the processed signal in order to gate or duck material that you don't want.

It features comprehensive controls including hysteresis and hold to allow you to precisely control when the gate opens and closes. It also features an optional, adjustable look-ahead so that you can ensure that initial transients are not cut off.

The UI provides detailed visualizations of the detector and gain signals so that you can see what's happening; which helps with tuning the gate.


The detector can be driven by the signal being processed or by a key-input fed by a bus or input channel. The detector includes an integrated detector sidechain EQ so you can tune the open and close trigger to a specific frequency band.

SuperGate has two processing modes: Gate and Duck. In Gate mode, the gain is reduced when the detector is below threshold. In Duck mode, the gain is reduced when the detector is above threshold. These modes combined with the Attack and Release curve models and the detector sidechain give you unprecedented precision and flexibility in gating and ducking operations. In fact, SuperGate is so tunable you can actually use it as fantastic transient shaper.

Often it is important to be able to hear what the SuperGate is removing rather than what it is passing through, so SuperGate also provides three listening modes so you can listen to the processed material, the detector source material or the source material that is being taken out of the processed signal.

Sonic EQ
SonicEQ UI

Sonic EQ 3d is an extremely flexible EQ with a long history. It's not just another EQ - it's special. Featuring six independent minimum-phase filter bands, each band offers your choice of 8 filter types and 5 function-specific equalization topologies.

This EQ traces its lineage directly back to the orignal process designed by Dr. James A. Moorer for Lucasfilm’s SoundDroid project that evolved into the Sonic Solutions Mastering Workstation. Metric Halo adapted the original design for the native Sonic EQ and for the DSP based Sonic EQ for Sonic Model 30x hardware.

This version now optimized for 3d DSP and adds integrated SpectraFoo spectrum analysis in the UI.

Processing functions include:

In every generation of Sonic EQ, two primary characteristics have remained consistent:

Its Sound - It has a full, sweet yet powerful musicality which brings a presence and clarity to literally anything you pass through it.

Its versatility - Whether your need is forensic restoration, sound design, high-end mastering, post-production, recording, re-recording, multi-tracking or live sound, the power and simplicity of this EQ package will get you the sound you are looking for faster and sounding better than you may be willing to believe.

You will find you can make EQ curves with Sonic EQ 3d that look completely broken, yet still sound perfectly clean and natural.

It is no understatement to say the Sonic EQ has been and still is one of the most highly respected and coveted digital equalizer packages on the planet.

Originally bundled exclusively with the Sonic Studio branded Model 302, 303 and 304 Firewire audio interfaces, it has been reborn in 3d with a cleaner and more responsive UI layout, SpectraFoo spectral and level metering and the higher order of musicality, precision and power inherent to the 3d DSP environment.

In collaboration with Make Believe Studios

Make Believe Studios is the brain-child of Grammy nominated Mixing and Mastering Engineer Rick Carson.

Rick set out to gather a comprehensive set of classic and rare analog processors coupled with an SSL console and Pro Tools to build a fantastic mixing environment in Omaha, Nebraska.

As a mix engineer, Rick found Metric Halo’s ChannelStrip to be a critical component of his mixing process, and so, when Rick decided to pursue building some new tools based on his experience, he reached out to Metric Halo to help him convert his ideas into reality.

When we heard what he wanted to do, we said “Let’s get going!”

The first 5 plugins from this collaboration are included with every mkIV unit as zero-latency modelled plugins running directly on the hardware.


MBEQ is an EQ that has been tuned to reflect Rick’s workflow. The user interface is designed to allow you to focus on a quick workflow and sound shaping, rather than a more analytical approach with numbers and knobs.

We also added what Rick calls the “Sauce”: an analog modelled topology based on the incredibly rare classic PYE TVT console modules created for the BBC in the 1960's. This Sauce module includes “Soul-Stolen” transformers and discrete amplifiers - it’s got a lot of character!

PYE Modules from Make Believe Studio

The output level impacts the euphonic distortion created by the analog design, so we added a pre-EQ drive control to allow you to tune precisely how hard you hit the output stage. There is also a post-output stage fader to allow you to fine tune the final output level. Since you can switch off the Sauce, the MBEQ is really two completely different sounding equalizers.

The UI focuses on the EQ itself to allow you to intuitively concentrate on the sound. It features a set of modifier keys that allow you to “play” the EQ like an instrument; with a little practice you can develop your chops and you can effortlessly dial in the tone you are looking for.

The EQ is preconfigured with 7 fully parametric bands and features the ability to add more… up to 12 bands.

Powerful. Intuitive. Sounds Unbelievably good. MBEQ.

MB Parallel 1, 2, & 3+4

“Have you ever wondered how they got that sound? Have you ever searched through old GearSpace postings at 3 in the morning hoping for some nugget of information to take your work to the next level only to find yourself further away from the goal than when you started?

The parallel process plugins are not going to help you sleep better at night, but they may help you get one step closer to a sound in your head!

Crafted after some of the best sounding tricks that I have personally come across, the parallel process plugins take complicated multi-step setup and breaks them down into very simple to use tools.

While they have some suggestions for intended use, we also suggest mixing and matching. You never know what sounds good until you try.

People have been loving a combination of Parallel 1 and Parallel 3-4 in series on a lead vocal; or try using Parallel 2 on a whole mix. None of those tools were designed for these positions but they sound great because they are tried and true tricks from the history of sound!

Parallel 1 is based on a west coast trick for incredibly thick snare drums. It has been found to lend warmth to almost any source you throw at it!

Parallel 2 Smacks. This tool will bring you a step closer to popping right out of a speaker and while originally designed for live drums it has made its way onto vocals and even masters!

Parallel 3-4 is classy top end. This will help anything with midrange sound like it went to a nicer college!!”

- Rick Carson
MB Good Math
GoodMath UI

“Good Math is just that. Good Math. If you want to try and get more technical with it you could try and say that it is something between a clipper, a limiter and rounding error but really… It’s just Good Math!”

- Rick Carson

Control Surface

MIO Console supports the industry-standard Mackie Control protocol as well as Avid’s EuCon control surface protocol. If you want tactile control over MIO Console, all you have to do is add one of the many supported control surfaces.


Faders, pans, mute, solo, headamp controls and Session transport controls are at your finger tips, and MIO Console is ultra-responsive - no lag between the surface and the DSP.

You can navigate through your mix from your surface. Moving an Aux to the faders is a single button push, and if your surface has a master fader, the selected bus master is always on the master fader.

The Monitor Controller is also fully supported on EuCon. EuCon support includes things like source and destination selection, gain, mute, dim, mono and speaker mutes. EuCon also supports gain, dim and mute control for Cues.

GoodMath UI

Control surfaces that support the Mackie Control master section also give you access to tactile control for the Monitor Controller.

The comprehensive EuCon support included with MIO Console means that you can use the free Avid Control app on iOS or Android to wirelessly control your mkIV mixer, headamps and monitor controller.

GoodMath UI

MH EdgeBus Cards: The Ultimate Plugins

Every 3d-based unit includes an MH EdgeBus Card slot to provide additional flexibility in configuration. The EdgeBus is a programmable high-speed plugin slot that accepts a variety of audio interfacing cards. Its programmable design and full access to all the audio clocks and power rails allows for the creation of a wide variety of digital, analog, processing and interfacing plugin modules.

The currently available modules include (with I/O channel counts listed):

The EdgeCard modules are field installable/swappable and the hardware automatically detects the type of the installed card. All EdgeCard audio channels are first class I/O and may be used just like the built-in channels; all I/O is available simultaneously.

You can use EdgeCards to interface with other systems, get additional I/O via third-party A/D/A converters, provide ingest paths for digital recorders, or to patch into your existing digital console (e.g. via MADI interfacing).

The high-channel counts achievable via MADI interfacing means that you can us your LIO-8/4p mkIVs as remote-controlled headamps, side car processing, or as a multitrack recorder for your console.


Format Conversion as a First-class Feature

The combination of MH EdgeBus Cards and MHLink provides built-in, low-latency format conversion between multiple digital audio formats. Within one box, you can convert from any of the input formats supported by the box and it's installed EdgeCard to any of the output formats supported by the box and card.

If you need to convert between formats supported by multiple EdgeCards you can simply MHLink two boxes with different EdgeCards to achieve the conversion.

So things like Analog ⇆ MADI, or MADI ⇆ AES, or AES ⇆ ADAT can all be accomplished without any third-party converter devices.

Kimleng Audio, Bangkok Thailand


Recording and playback capabilities have been a part of Metric Halo products since 1997 with the Capture Panel in our SpectraFoo Audio Analysis and Metering software package.

In 2002, elements of SpectraFoo’s Capture Panel found a new home as the multitrack MIOConsole Record Panel, included with each Mobile I/O 2882, ULN-2, and later with the second-generation LIO-8/4p and LIO-8 devices.

Renowned for its rock-solid reliability, sound quality and ease-of-use, the MIOConsole Record Panel remains a go-to recording tool for high-end mastering, audio preservation, live recording and technical analysis engineers today.

Every mkIV unit includes Session - the new tracking DAW that we evolved from the humble beginnings of the Record Panel.

Not limited to just recording, Session includes:

The same EDL (edit decision list) Engine that enables overdubs also supports audio editing functionality including segment drag, drop and copy, timeline selections, cut copy and paste, all with integrated fades.

Since Session is part of MIOConsole3d and has deep control of the hardware, overdubs are performed with dynamic monitor switching on record-enabled channels in the hardware mixer with crossfades on punch in/out, and with the ability to monitor both recorded tracks and live inputs through zero-latency DSP processing.

We have included track export functionality so that when you are ready to transition from tracking to production or mix down you can easily migrate your tracks to the DAW(s) of your choice.

The combination of zero latency monitoring with signal processing, automatic routing, pre-recording, overdubs and editing allows you to optimize your multichannel recording process. Whether you are doing long form live recordings, take-based recordings, or full-blown multipass recordings with overdubs Session will allow you to capture quickly and easily with ultimate fidelity and stability.

Session’s level-based trigger, loop-recording, and autopunch functionality makes it just as easy to record yourself by yourself as it is to record for others.

In addition to DAW-style timeline recording, Session supports the original Take-based field recording model that enables easy import of takes into other DAW systems and also enables take-based recording workflows simultaneously with the session based workflow.

Session supports BWF time stamping from SMPTE LTC and the integrated sample-accurate LTC time code reader. LTC can be input via any input, or via the dedicated SMPTE LTC input port included on every LIO-8/4p mkIV unit.

Session also includes extensive recording metadata in each file, including support for iXML.

The combination of pre-roll, time stamping, iXML metadata and polyphonic file recording allow you to optimize the take-based recording workflow for industry standard field recording operations.

Combined with the Mixer, Session provides a complete Production Mixing and Recording solution for for on-set recording for Film and TV.

Session Features

Kimleng Audio, Bangkok Thailand

Stand-alone Operation

Flexible signal routing and sophisticated patch and preset management systems as well as a comprehensive set of front panel controls are also featured in the LIO-8/4p mkIV. The mkIV’s front-panel controls allow the unit to function equally as well as a stand-alone Mic Pre/Converter system. In standalone mode, the mkIV operates with the converters directly routed to and from the AES I/O, and the analog sends allow purely analog operation of the preamps.

As a standalone converter, the LIO-8/4p mkIV provides a 24bit/192kHz eight channel front-end with 4 world-class boutique-quality ULN-R mic pres for any recording system. It also functions seamlessly as an analog monitor controller, making it ideal as a digital headphone amp and studio monitor controller.

Boot States / Snapshots

LIO-8/4p mkIV has support for saving and recalling hardware Boot States and Snapshots.

Boot States are automatically applied by the hardware when it is booting up. Snapshots may be recalled manually from the front panel.

When you save a snapshot to the hardware, everything required to restore the current running state of the hardware is gathered up and stored on the hardware. This includes:

On boot/recall all the settings listed above are set on the hardware (including all the connected units in an MHLink domain. The LIO-8/4p mkIV also provides extensive front panel controls that allow you to change a wide variety of hardware parameters after the recall of the boot state. This combination of features allows you to configure your hardware for Standalone operation - for example you can configure your LIO-8/4p mkIV as a standalone Mic Pre, A/D/A converter, Format Converter or Monitor controller (or any combination of these functions).

Features in Detail

System Requirements




What’s Included in the Package

Each LIO-8/4p mkIV includes the following items:

Differences between LIO-8/4p mk IV and LIO-8/4p 3d

LIO-8/4p mk IV features:

LIO-8/4p mk IV LIO-8/4p 3d
Digital Design Gen 3 Gen 3
Analog Design Gen 4 Gen 3
Converter Design Gen 4 Gen 2
Power Consumption 18 Watts 29 Watts
Converter RTL 18 samples 116 samples
Unity-gain analog loop Yes No
Relay Mute Yes No