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An introduction to Metric Halo ULN-8 mkIV, based on information from the maker and distributors: what it does, how to use it and who it may suit. It is not scored.
What is ULN-8 mkIV?
The ULN-8 mkIV is a 1U interface from Metric Halo that integrates eight ULN-R mic preamps, 8-channel A/D/A, a monitor controller, a 128-channel by 64-bus mixer and DSP. Distributor Media Integration presents it as a recording and mixing console.
The ULN-R preamps provide up to 90 dB of digitally controlled analog gain, recallable in 0.5 dB steps, with per-input phantom power, a non-degrading pad and inputs up to +20 dBu that can also serve as line inputs. Metric Halo's Character processing lets each input lean from clean to tube-like.
Analog send outputs allow use as a remote-controlled preamp or let you insert analog gear between preamp and converter. There are 2 guitar/bass DI inputs and 8 channels each of AES in and out.
The distributor page says new purchases include a free MH Production Bundle v4 license to mark its release. Compared with the previous ULN-8 3d, converter round-trip latency falls from 116 to 18 samples and power draw from 32 W to 20.7 W.
Eight ULN-R mic preamps
Eight boutique preamps are built in, with up to 90 dB of gain recallable in 0.5 dB steps, and the maker says they handle both low-output mics and high-SPL sources.
Analog send and split
A pre-A/D analog send gives a fully analog split for backup recorders or mixers, and send/return mode lets you patch analog processors in.
Fourth-generation converters
DC-coupled A/D/A with no low-frequency filtering on the D/A. Round-trip latency is much lower than the previous generation, and unity-gain analog loops are supported.
Relay mute and low power
Relay output muting prevents clicks and pops at power up and down. It is fanless and draws 20.7 W.
Over 100 DSP plug-ins
The Production Bundle, +DSP Bundle, Make Believe Bundle and Sontec MES-432D9D are included at no extra cost.
MHLink, EdgeBus and Session
MHLink carries up to 256 channels at 192 kHz over Cat5e up to 100 m, an EdgeBus slot expands I/O, and the Session tracking DAW is integrated.
Specifications
| Item | Details |
|---|---|
| Size | 1U |
| Mic preamps | 8 x ULN-R (up to 90 dB, 0.5 dB steps) |
| A/D and D/A | 8-channel A/D with analog trim, 8-channel D/A with analog gain |
| DI inputs | 2 channels |
| Digital I/O | 8-channel AES in and out |
| Mixer | 128 channels x 64 buses, 192 kHz |
| Round-trip latency | About 0.9 ms (44.1 kHz) / about 0.2 ms (192 kHz) |
| Converter RTL | 18 samples (116 on ULN-8 3d) |
| Power | 20.7 W (32 W on ULN-8 3d); 25 W with phantom on all channels |
| Connectivity | MHLink (Gigabit Ethernet), USB-C |
| System requirements | macOS 10.9 or later (Intel/Apple Silicon); USB or Ethernet port |
What is included and system requirements
- ULN-8 mkIV unit
- IEC power cord
- 19 V 60 W external power adapter
- CAT5e Ethernet cables (2 ft and 10 ft)
- USB-A to USB-C cable
- Two rack ears and rubber feet
- Jumper pins, warranty/registration card
- MH Production Bundle v4 license with new purchases, per the distributor page
How to use it
- Place the unit in a rack or on a desk and connect power.
- Connect to the Mac over USB-C or MHLink.
- Launch MIOConsole.
- Plug mics into the preamp inputs and switch on 48V if needed.
- Set gain and choose a Character setting.
- Build routing in the mixer and set monitor outputs.
- Send audio to your DAW via CoreAudio.
- Save a Boot State so it can run standalone.
Tracking bands and live instruments
The eight preamps may suit multi-channel tracking.
Location recording
Being fanless and low-power, it might suit quiet environments.
Monitor management in a mastering room
It could double as monitor controller and D/A.
Remote mic preamp
Over MHLink it could sit up to 100 m away as a stage-side preamp.
Who it may suit
- People who want eight preamps and converters in one box
- Those who want an integrated monitor controller
- Mac-based studios
- Users who may expand over MHLink later
Good to know before you buy
- The listed requirement is macOS; Windows and others connect as USB Class Audio.
- It sits in a high price range, which is a large investment for a home studio.
- There are many settings, so expect a learning curve.
- The bundled-license offer may change over time.
How it differs from similar products
We do not pick a winner; the official figures are placed side by side.
LIO-8 mkIV
The ULN-8 mkIV includes eight ULN-R preamps as standard, while the LIO-8 mkIV makes them optional. A/D/A, mixer and DSP are shared.
ULN-8 3d
Per the distributor's table, the ULN-8 mkIV has 4th-generation analog, 18-sample RTL and 20.7 W, while the ULN-8 3d has 3rd-generation analog (2nd-generation converters), 116 samples and 32 W.
Price
Please check the official page for the price.
See ULN-8 mkIV on the product page
Sources: minet.jp mhsecure.com (checked 2026-10-27)
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