ULN-2 3d

Real mic pres for real recording

Out of Stock, not currently available for order

The ULN-2 3d is the result of our dream to create a piece of audio gear that provides unbelievable audio quality while at the same time offering a degree of mobility, functionality, convenience and expandability that was simply not possible until now.

The successful integration of world-class analog stages, excellent A/D/A conversion, and the amazing routing, digital mixing and MHLink connectivity enabled by the 3d platform, places the ULN-2 3d in a unique position among computer audio interfaces.

The ULN-2 3d is a portable, high–quality, modular multi-format audio converter, interface, and processor.


Each ULN-2 3d integrates:

  • Exceptional A/D Conversion (2 channels)
  • Exceptional D/A Conversion (2 channels - line level)
  • Exceptional D/A Conversion (2 channels) with independent:
    • Analog domain monitor control
    • Exceptional headphone output with dedicated Volume control
  • MH ULN preamps (2 channels)
  • AES I/O (2 Channels)
  • SPDIF I/O (2 Channels)
  • ADAT I/O (8 Channels)
  • All Analog I/O supports 96k
  • All Digital I/O supports 192k
  • 128 Channel x 64 bus mixer (up to 192k)
  • Instantiable DSP processing with over 100 plugins
  • Integrated surround-capable Monitor Controller
  • Incredibly accurate DPLL clock with ultra-low jitter
  • Seamless hardware multi-unit unification over MHLink (mixer, routing and transport)
  • MH EdgeBus Card slot with support for AES/SPDIF/MADI/ADAT/TOSLINK/MIDI (depending on card)
  • SMUX support for ADAT and MADI
  • Front panel metering and control with dedicated gain knobs
  • Bullet-proof recording with the integrated Record Panel
  • MIO Console 3d
  • MHLink Ethernet connectivity
  • USB-C connectivity

Amazing Mic Pres

ULN stands for Ultra Low Noise and the Mic Pres in ULN-2 live up to the name. Providing massive gain (up to 72 dB) with an EIN of -130.5 dBu, fantastic detail and an ultra-fast slew rate, the ULN Mic pres are up to the most demanding recording situations you can throw at them. Each input supports independently switchable P48 phantom power.

They are not just great for preamps on an interface; they are great preamps, full-stop.

The combination of the super transparent ULN preamp and Metric Halo’s exclusive insertable Character Component Modeling Processing provides flexibility and sound quality that’s unavailable on any other interface. 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 desire.

The preamp input path on the ULN-2 also supports input levels of up to +20dBu with its switchable input trim, 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).

In all cases the input noise of the mic pre is incredibly low, providing an EIN of -130.50 dBu (@ 60dB of gain) with a mic that has a 150 Ω source impedance.

Jensen Transformer option for ULN-2

The ULN-2 possesses virtually every characteristic that is coveted in a Mic Preamp: exceptionally low noise at all gains, exceptionally high gain, excellent common mode and RFI rejection, incredibly flat frequency response, and ultra-low distortion. It simply increases the level of what you put into it without having to consider the nature of the source: Dynamic Mics, Phantom Powered Mics, Ribbon Mics, Instrument or line level signals are all handled with equal ease and quality.

The ULN-2 is an incredibly good Mic Pre, but sometimes you want something that isn’t quite “so pristine”. It is well known that a certain amount of low-order harmonic distortion has a way of adding “depth” and “sheen” to everything — which explains the high regard for classic transformer coupled preamps.

With the transformer option installed, the ULN-2 acquires that classic character. A few years ago, we fitted a prototype ULN-2 with a pair Jensen JT16-A's just for fun. We found that there were some very nice benefits to transformer coupling the input stage of the ULN-2. The Transformers impart a more “glossy”, “smoothed” sound than the capacitively coupled ULN-2, which simply faithfully passes the source. Sonically, it's kind of like the difference between images shot on film and images shot in HD.

A second benefit is that the transformer completely electrically isolates the preamp from the source – raising the common mode rejection above its already excellent performance, and providing a measure of confidence when dealing with the unknowns of location sound.

The transformer option requires factory installation; we have to remove the cap coupling from your existing ULN-2 and carefully add the Jensen transformers to the signal path. When you order your upgrade, we will issue an RMA for you to send your unit into the Custom Shop and our technicians will install the option for you. Turn around time is typically 1 week from date of receipt of the unit. If you simply want to order a new ULN-2 with the transformer option pre-installed at the factory, you can do that as well; this version of the ULN-2 is available directly from Metric Halo via Metric Halo Direct or from your dealer.

Balanced Analog Sends and Returns

The ULN-2 also features balanced analog inserts for each input. This lets you use ULN-2 as a standalone analog Mic pre/direct box; use the sends as an active splitter to drive a backup recorder, or even patch in analog dynamics processing between the Mic Pre and the integrated 24bit/96kHz A/D converters.

Flexible Powering Options

The 4-pin XLR power port on the ULN-2 allows you to power the unit with a variety of readily available broadcast battery systems. The 4-pin power port is compatible with power sources having the following characteristics: 9-30V DC, Pin 4 Hot, 15 Watts.

A/D/A Conversion

Audio converters stand at the heart of every digital audio product. If the conversion is not up to snuff, you might as well toss the product out the window -- as the best you can hope for is that it doesn’t damage your precious audio (or reputation) too much. No matter how good the DSP is, if your converters don’t capture (or render) your audio accurately you are starting at a deficit.

RackAudio conversion is something that is more than the sum of its parts. You can’t simply look at the converter chip and determine how something is going to sound. Excellent audio conversion requires careful attention to detail and the tuning of every element of the entire conversion system; this includes the analog front end, the power system, the clock and the converter chip 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. As any system can be no better than it’s weakest link, it is vitally important that the component you use to capture and render all of your audio is not the weakest link in your system.

The analog converters in the ULN-2 provide exceptional conversion that “simply gets out of the way.” Metric Halo’s converter philosophy is to come as close to the original analog signal as possible; converters should not color your signal. By accurately reproducing your input, the ULN-2 3d allows you to properly capture the nuance of your sources, whether they be mics, tape decks or classic analog gear.

Accurate conversion means that when you monitor your production, you actually hear what you will deliver - not some approximation with euphonic distortions introduced by your monitoring chain. And if you add euphonic distortion with an analog loop, you can be sure that the results will be captured accurately. In other words, the ULN-2 doesn’t distort the distortion. You choose where and when your signal is processed.


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 ULN-2 3d integrates two different monitoring options.

The first option is via the balanced monitor output connection which features an analog, front-panel mounted volume control. The D/A for this path is shared between the monitor output and the headphones - each with independent gain control on the front panel.

The second option is a transparent digital Monitor Controller to ensure that you can use with the line output path or via external converters or digitally connected speakers.

The Monitor Controller in the ULN-2 3d provides sophisticated monitor control features that are only available in dedicated monitor controllers that paradoxically cost more than the ULN-2 3d. These features include:

  • Multiple source selection
  • Multiple speaker output selection
  • Shared speaker set support
  • Per speaker gain and delay
  • Per speaker solo/mute control
  • Output path calibration support
  • Multichannel support from Stereo up to 7.1.4 Surround (Dolby Atmos®) with external converters
  • Mono fold-down
  • Mute and Dim
  • Analog domain gain control
  • Talkback
  • Listenback
  • Multiple cue output support
  • PFL/AFL integration with the mixer
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 ULN-2 3d includes a high quality headphone amplifier fed by the monitor path D/A conversion with independent analog domain gain control. So you don’t need to add a headphone amp to your system.



Cue Control

In addition to monitoring the mix in your control room, multitrack production requires providing multiple output cues to performers and other stakeholders (such as 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 are not Mixes. Cues are output points with gain and routing controls that can be fed by specific mixes, the current monitor controller source, or a mix of a source and the talkback signal. They serve as named output mults with direct access to associated output gain controls.

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 MC to any sub-set 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.


ULN-2 3d includes 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.

Each ULN-2 3d 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. ULN-2 3d 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. 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.


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):

  • AES/SPDIF EdgeCard (4 in/4 out)
  • DB-25 AES EdgeCard (8 in/8 out)
  • SPDIF + MIDI EdgeCard (2 in/2 out + MIDI I/O)
  • SPDIF + 2x ADAT EdgeCard (18 in/18 out)
  • 2x SPDIF + 2x ADAT EdgeCard (20 in/20 out)
  • 4x ADAT EdgeCard (32 in/32 out)
  • 2x MADI Optical EdgeCard (128 in/128 out)
  • 1x MADI Optical + 1x MADI Copper EdgeCard (128 in/128 out)
  • 4x MADI Copper EdgeCard (256 in/256 out)

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 use your ULN-2 as additional 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.

Integration for the Win

By implementing all the functions of a complete audio front end in a single package, the ULN-2 is able to provide unprecedented power and quality in a lightweight, low-power consumption, single RU hardware unit. This integration provides significant benefits to the owner in the form of reduced cabling (lower cost, weight and less opportunity for failure), weight, power consumption, and cost, while at the same time providing unprecedented performance.

In 3d, the command architecture, conversion and DSP processing systems were all designed in concert with the clocking and transport architecture, resulting in a system with superior sound compared with external clocking systems costing tens of thousands of dollars.

The MHLink routing and transport architecture allows you to build a system with units up to 100 meters apart with no added latency. Audio and clock transport with up to 256 channels of audio (at 192k) is accomplished with light-weight, inexpensive, commodity Cat 5e cabling, that is available virtually anywhere on the planet 24/7. And yet, the entire system still appears to the host computer as a single unified interface.

What does this integration mean to you?

Rather than pay for duplicate case work, duplicate power supplies and redundant interconnects, you get a product where all the components are engineered to work together and everything you pay for is dedicated to providing functionality towards the execution of your task.

The benefits don’t stop there. By tuning all the functional blocks of the system and removing external interconnects, the ULN-2 provides enhanced performance and reduced chance of failure from external influences. Connectors and cables are all potential sources of failure and interference. By eliminating preamp to converter and converter to interface cabling, these sources of cost and potential failure and interference are also eliminated. Internal operating levels within the box are tuned for optimal performance.

The ULN-2’s integrated design provides maximal performance with a minimum use of material and power.

ULN-2 Key Benefits at a Glance

  • Exceptional Converter Quality
  • Exceptional, Boutique–Quality Mic Preamps
  • Flexible, Integrated Analog-Domain Monitor Controller
  • Up to 96k Sample Rate Support
  • Analog, AES, ADAT, Ethernet, USB and EdgeCard Interfacing
  • Rock Solid Stability: Mature, Real-World-Tested Firmware, Software and Drivers
  • Hardware-based MHLink multi-unit unification network
  • Instant Access to Tactile Controls
  • Comprehensive Metering — you always know what is going on
  • Works with or without a Computer
  • Metric Halo’s Exclusive instantiable Character — from ultra clean to nice and gooey
  • Integrated ultra-low-latency instantiable processing with plenty of DSP power to run it
  • Most Compact, Lowest Weight, Lowest Power and Lowest Price in its Class

Suite Solution

With everything you need to record, mix, process, and master audio (just add your DAW of choice and transducers), the ULN-2 is your one-stop solution for recording, edit, mix and mastering suites. Even if you are using a DAW or recording system that does not support the ULN-2 Ethernet or USB interface, the unit’s standalone operation and standard AES and analog interface (and optional ADAT or MADI interfaces) allow you to use it as the Audio Front End and Monitor Controller for Pro Tools HD, standalone and PC based recording systems.

The ULN-2 Starts Where Other Interfaces End

All these features make for an impressive package, but we’re just beginning. The ULN-2 is built around Metric Halo’s 3d DSP platform, giving you the power to run a sophisticated mixer with up to 128 inputs and 64 busses across multiple boxes. Of course you can run plug-ins inside the box as well. It also includes a full +DSP license, giving you the ability to create powerful mixing, sound design and master plug-ins. Beauty and brains, all in 1RU.

At Home in Any Situation

ULN-2 is the perfect tool for capturing audio wherever inspiration hits, in the studio or on the road. Use a ULN-2 for capturing your ideas and with ultimate quality. Add more 3d units if you need more channels. Location sound engineers can now capture the two mix — anywhere, anytime.

When you’re done recording, use the ULN-2 in the studio as an extremely high quality audio interface to transfer your tracks into a DAW. You’ll be amazed at the sound of this box! And weighing only 4 pounds, and a little larger than a laptop, you can be the first one out of the gig, with no hassle.

The ULN-2’s exceptional inputs and outputs, coupled with Metric Halo’s exclusive Character processing, provide flexibility and sound quality unavailable on any other interface. You can transition from a wire-with-gain to a gooey tube pre with one click of the mouse, and every input and bus can have the right character for the material you are recording.

The ULN-2 is the only unit in its class with an on-board processing engine that supports fully instantiable processing, allowing you to use Metric Halo’s world-renowned signal processing effects without sacrificing your computer’s processing power or introducing any additional latency in your monitor path. From MIOStrip to HaloVerb, the ULN-2 comes with a full +DSP license that provides all the basic production processing you need — and more. And remember, this one rack space audio interface has the ability to run entirely from any DC power source (9V-24V), making it truly and completely mobile.

Organically Scalable

A unique feature of the Metric Halo 3d system is that MH’s interfaces work as well as a group as they do individually. Mix and match ULN-2 with LIO-8 3d, 2882 3d, and ULN-8 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. By standardizing on the 3d platform, each member of the band can have ultimate quality while working alone, and the band can have huge track counts when playing together. You can’t lose!




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 ULN-2. The ULN-2’s front-panel controls allow the unit to function equally as well as a stand-alone Mic Pre/Converter system. In standalone mode, the ULN-2 operates with the converters directly routed to and from the AES/SPDIF I/O, ADAT or TOSLINK, and the analog domain sends allow purely analog operation of the preamps.

As a standalone converter, the ULN-2 provides a 24bit/96kHz two channel front-end with 2 world-class boutique-quality ULN 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.


The ULN-2 3d supports a variety of applications. For studio recording, it provides the highest quality interface to a DAW, offering sound processing or simple file transfer between workstations. Its exceptional sound quality makes it perfect as any studio’s primary analog to digital conversion and monitoring chain. Songwriters and engineers can use the ULN-2 to record and edit on the road, in the hotel, while traveling, or anywhere that inspiration strikes.

The ULN-2 is suitable for broadcast applications, too. It offers instant playback of two individual stereo sends for music cues or sound effects. The compact package and portable power features mean that the unit can go anywhere users need to work, and make on-site fixes or edit location recordings without the need to send files back to the studio, saving valuable time before air.

In the live performance arena, in addition to operating as a remote recorder for archiving performances or to play out backing tracks and musical cues, the ULN-2 can operate as a soft-synth mixer and I/O interface. The ULN-2 is also a great addition to a live sound engineer’s setup, providing a simple and efficient tool for analysis and system venue tuning with SpectraFoo.

Features in Detail

  • 2 Channels of Exceptional 96k A/D converters
    • Exceptionally flat, low-distortion A/D conversion
  • 2 Channels of Exceptional 96k D/A converters (line-level)
    • Exceptionally flat, low-distortion D/A conversion
  • 2 Channels of Exceptional 96k D/A converters with integrated headphone amp/monitor amp
    • Dedicated, analog controlled high-power headphone amplifier
    • Independent monitor gain
  • 2 Channels of Exceptional Ultra-Low-Noise Preamps
    • Custom designed Switch Controlled analog preamps
    • Discreet gain and trim stages for ultra-high headroom operation
  • Analog Send/Return architecture for analog access to preamps (pre A/D)
    • Analog domain sends from preamps (mult’ed pre-A/D)
    • Analog only preamp operation capable
    • Integrated switching to allow insert of external analog processing pre-A/D
  • Integrated Surround Monitor Controller
    • Provides switching between any set of user specified sources (Host, USB, AES, Analog, ADAT, MADI or Mix)
    • Analog domain gain control for monitor output from Front Panel
    • Supports input and monitor paths from Mono to 7.1.4 (with external converters)
  • 4 Channels of 192k capable AES/SPDIF Inputs and Outputs
    • Available as computer I/O or direct routed I/O for converters
    • Support full channel count at all sample rates
    • Professional interfacing
  • 8 Channels of SMUX capable ADAT Inputs and Outputs
  • Comprehensive Front Panel Controls
    • Full support for standalone converter and preamp operation
      • Gain selection
      • Phantom power selection
      • Input source selection
      • Phantom power control
    • Tactile Control of Input and Output gains
    • Tactile Control Headphone level
    • Tactile Control Monitor Stereo Output gain
    • Preset recall
  • Comprehensive, High Resolution 10 Segment Precision Front Panel Metering
    • Real, functional metering for analog inputs and outputs
  • Comprehensive Clocking (Internal, Word Clock, AES, SPDIF, ADAT, MADI, MHLink)
  • Dedicated internal clock sources for all rates
  • Optional MIDI I/O (with EdgeCard)
    • MIDI Input and Output on standard DIN connectors
    • MIDI transported to computer
  • Rock-solid, time-tested fifth-generation software and drivers
  • Integrated Mixing and Deep Instantiable DSP Processing (Includes Full +DSP License)
    • Fully configurable multibus mixer with surround support (up to 7.1)
    • Full Send/Return architecture
    • Ultra-low latency, on-the-metal monitoring
    • Insert model for inserting zero-latency plugins
    • Insertable +DSP plugin graphs for configurable processing
    • Insertable graph macros for complex, pre-configured processing
    • Includes over 100 high-quality processing plugins, including:
      • MIOStrip — channel strip processing
      • Dynamics (Compressor and Limiter)
      • Transient Controller
      • EQ (6 band and 12 band)
      • HaloVerb
      • Signal Processing primitives
      • Crossovers
      • and much more…
    • Per-channel and Per-bus Insertable Character™
  • MHLink Interfacing between boxes
  • Ethernet Interfacing to computer with MHLink Audio
    • Supports Mac OS X v. 10.8.5 and newer
  • Bidirectional Control Surface Support
    • Eucon Control Surfaces
    • Mackie Control Protocol Control Surfaces
  • Integrated Multichannel Recorder (Record Panel)
    • Multichannel, multi-box tape-style high-performance recorder
    • Exceptional Stability and Sound Quality
    • Realtime waveform display
    • Extensive File Format support (BWF, WAVE, CAF, AIFF, SD2)
    • BWF time-stamping from TOD or LTC (any input channel or dedicated SMPTE input)
    • Support for basic BWF metadata
    • Support for limiting record file size and seamless file breaking
    • Seamless manual file breaking (with time-stamping)
    • Support for mirrored recording (recording to multiple drives at once)
    • Pre-roll/Pre-record
    • Dreamcatcher™ Level Based trigger
    • Timecode based trigger
    • Monophonic and polyphonic recording (determined by source strip width)
  • DC-Powerable
  • High quality, custom designed formed powder-coated aluminum case
    • Strong
    • Light weight
    • Scratch and fingerprint resistant
    • Smooth contours for snag-free transportation in a gig-bag
    • Rack-mountable with included rack-ear kit
  • Exceptional Power Performance (only 8 Watts)
  • Low mass (4 lbs / 1.8 kg)
  • Extremely Compact (everything in 1 RU)
  • Future Proof, Expandable, and software-enhanceable

  • Specifications

    Mic Inputs
    Stepped Gain Range +6 dB – +72 dB (6 dB Steps)
    Gain Range with Trim -14dB – +70 dB
    Input Impedance 3.3 kΩ
    Harmonic Distortion @1kHz
    (+9dBu in @ 6 dB Gain)
    Intermodulation Distortion
    1k component
    (19 kHz/20kHz @ +8dBu)
    -96 dBu
    Equivalent Input Noise (E.I.N.)
    20 Hz – 20 kHz Flat @ 72 dB Gain
    150Ω Source -130.5 dBu
    50Ω Source -132.0 dBu
    0Ω Source -134.0 dBu
    Frequency Response
    18 Hz – > 20 kHz ± 0.1 dB
    8 Hz – > 50 kHz ± 1.0 dB
    3 Hz – >100 kHz ± 3.0 dB
    Crosstalk @1kHz
    trim link engaged -107 dB
    trim link disengaged -132 dB
    Max Gain 72 dB
    Preamp Headroom 20 dB above Digital Clip
    Phantom Power +48v Regulated, high current, individually
    switchable, P48 test compliant, short circuit/
    hot-swap protected
    Physical Specs
    Controls Stepped Gain (12 steps 6dB – 72 dB)
    Continuous Attenuator on return
    Attenuation link
    Mic/Line Select switch
    Independent Monitor Volume Controls
    Independent Phantom Power Controls
    [W x D x H]
    13.75” x 8.25” x 1.73”
    34.9 cm x 21 cm x 4.4 cm
    Weight 4 lbs
    1.8 kg
    Rating 8 watts @ 9 – 30v DC
    Connectors 2.1 mm Coaxial
    4 pin XLR Broadcast Battery

    What’s Included in the Package

    Each ULN-2 includes the following items:
    • One ULN-2 unit
    • One IEC Power Cord appropriate for your area
    • One 18-volt 60-watt world-ready external power supply
    • One 12” CAT5e Ethernet Cable
    • One 14’ CAT5e Ethernet Cable
    • One USB-A to USB-C Cable
    • Two Rack Ears w/ fasteners
    • Rubber feet
    • Warranty/Registration Card

    Which interface is right for me?

    While all Metric Halo interfaces are multi-purpose, each has characteristics that make it shine in one use or another:

    • ULN-8 3d: Our top of the line, archival quality unit. The ULN-8 has the quality and features to handle the most demanding jobs. Perfect for everything from classical recording to the mastering suite, or any user that needs ultimate power and flexibility.
    • LIO-8 3d: All the audio quality of the ULN-8, minus the mic pres. Perfect for the editing suite, recording with your own pres or interfacing your analog console. In true MH style, the mics pres can be added in 4 channel groups if your needs change.
    • ULN-2 3d: Two channels of boutique quality mic pres in a small package. The ULN-2 is at home in the mastering studio as well as your home studio. Perfect for the discerning recordist who doesn’t require high channels counts but demands high quality and appreciates portability.
    • 2882 3d: Eight channels of analog I/O that fits in your backpack. The 2882 is clean without being pristine and packs a lot of power.

    Use the following table to see the notable differences between the interfaces.

    Feature ULN-8 3d LIO-8 3d ULN-2 3d 2882 3d
    Converter Technology 2nd Generation 2nd Generation 1st Generation 1st Generation
    Preamp Technology 3rd Generation Optional (1) 2nd Generation 1st Generation
    Analog Technology 3rd Generation 3rd Generation 2nd Generation 1st Generation
    DSP Technology 3rd Generation 3rd Generation 3rd Generation 3rd Generation
    Box-to-Box MHLink MHLink MHLink MHLink
    Computer Interface Ethernet/USB Ethernet/USB Ethernet/USB Ethernet/USB
    44.1k - 48k
    88.2k - 96k
    176.4k - 192k D/A & Digital D/A & Digital
    Channels of A/D 8 8 2 8
    Mic pres 8 0, 4, 8 (1) 2 8
    Gain 91.5 dB 91.5 dB (1) 72 dB 42 dB
    Jensen Option n/a n/a n/a
    Noise floor 117.9 dB 117.9 dB 110 dB 110 dB
    Insert points 8 0 (8 sends) 2 n/a
    Dedicated DIs 2 2 n/a n/a
    Metering 15 Segment Multicolor 15 Segment Multicolor 10 Segment
    Fixed Color
    10 Segment
    Fixed Color
    Channels of D/A 8
    4 8
    Output Control Digitally Controlled Analog Digitally Controlled Analog Analog (Monitor Outs), Digital (Analog Outs) Digital/Analog hybrid
    Output Control UI FP + Computer FP + Computer FP Only (Analog)
    Computer Only (Digital)
    Computer Only
    Monitor Controller Analog Domain Analog Domain Digital Domain Digital Domain
    AES Digital I/O 8 channels
    (single wire)
    8 channels
    (single wire)
    2 channels (2)
    via EdgeCard
    2 channels (2)
    via EdgeCard
    Optical Digital I/O via EdgeCard via EdgeCard 8 channels ADAT(3)
    or 2 Channels TOSLINK
    8 channels ADAT(3)
    or 2 Channels TOSLINK
    Wordclock I/O
    Multipurpose encoders 9 9 n/a n/a
    Tact Switches 7 7 2 (snapshot selection) 2 (Mute & Dim)
    Gain Control UI FP + Computer FP + Computer FP Only Computer Only
    Gain Control Encoder Encoder Switch/Pot Computer
    Gain Style Digitally Controlled Analog Digitally Controlled Analog Analog Digitally Controlled Analog
    3d Card
    Ultra-low Latency Mixer
    Basic DSP Plugin Bundle
    +DSP license
    Number of channels to/from Computer over USB 12 12 12 12
    Number of channels to/from Computer over Ethernet

    up to 128

    up to 128

    up to 128

    up to 128

    Bus powerable? No No No No
    DC powerable?
    Power Switch No No
    Audio I/O connectors DB-25 DB-25 XLR and TRS XLR and TRS
    SMPTE I/O n/a n/a
    MIDI I/O via EdgeCard via EdgeCard
    Dimensions 17" x 13" x 1.72"
    432 x 330 x 44 mm
    17" x 13" x 1.72"
    432 x 330 x 44 mm
    13.5” x 8.25” x 1.73”
    343 x 210 x 44 mm
    13.5" × 11" × 1.73"
    343 x 279 x 44 mm
    Weight 6 lbs
    2.7 kg
    6 lbs
    2.7 kg
    4 lbs
    1.8 kg
    4.5 lbs
    2 kg
    Suggested retail price $4495 $2995 $1595 $1795
    Early Access price $3195 $2495 $1395 $1595


    1: 4 or 8 channels of 3rd Generation ULN-R mic pres may be installed as a factory option or at a later time.
    2: AES and SPDIF active simultaneously and independently
    3: ADAT supports SMUX; operation supports up to 192 kHz with a corresponding reduction in channel count

    System Requirements

    • Any Mac that supports macOS 10.8.5 or newer with a 64-bit Intel Processor
    • One of:
      • USB port
      • Built-in Gigabit Ethernet Port
      • Thunderbolt Gigabit Ethernet Adapter
      • Thunderbolt Dock with Gigabit Ethernet Adapter
      • USB3 to Gigabit Ethernet Adapter
      • PCIe Gigabit Ethernet Card


    • macOS 10.8.5 or newer required


    • All CoreAudio compliant software is compatible with Mobile I/O, including:
      • Cubase
      • Digital Performer
      • GarageBand
      • iTunes
      • Abelton Live
      • Logic
      • Studio One
      • Bitwig
      • Nuendo
      • PreMaster CD
      • soundBlade
      • WaveBurner
      • Pro Tools
      • Final Cut Pro
      • and hundreds more…