Metric Halo
Summary
Abstract
Metric Halo is a niche but deeply respected manufacturer of professional audio interfaces, best known for the LIO-8 and ULN-8. What sets Metric Halo apart is an unprecedented hardware upgrade program (the “3d” upgrade), allowing owners of units from the early 2000s to bring their hardware up to current specifications for around $600. Combined with excellent conversion, powerful onboard DSP, and Ethernet-based networking between units, Metric Halo interfaces have earned a devoted following among engineers who prioritize longevity, flexibility, and sound quality above all else.
Key Characteristics
- Type: Ethernet-networked Audio Interface with onboard DSP
- Topology: High-quality AD/DA conversion with powerful onboard DSP processing
- Notable Features: 3d hardware upgrade program (future-proofing legacy units), Ethernet networking between multiple boxes, onboard DSP for processing and monitoring, MIDI/EUCON/Stream Deck controller support, insert send/return loops on ULN-8, remote preamp control over network
Use Cases
Metric Halo interfaces are the choice for engineers who want a piece of gear that truly gets out of the way and lasts for decades. The Ethernet networking capability is particularly valued for recording setups where multiple rooms need to share a single system: boxes in the live room can have their preamps controlled remotely from the control room. Engineers who have left the UA ecosystem frequently land on Metric Halo, citing the combination of low latency, transparent conversion, and deep DSP as the primary draws. The LIO-8 is ideal for engineers who bring their own preamps, while the ULN-8 adds high-quality built-in preamps with hardware insert loops.
Settings & Sweet Spots
- Pair with a Stream Deck+ or EUCON controller for monitor volume and routing control. Bryan DiMaio calls this combination “sick” for daily workflow.
- Run at a 32-sample buffer for extremely low roundtrip latency. Bryan DiMaio notes that RME has the lowest latency driver, with Metric Halo a close second.
- The 3d upgrade for legacy units is the defining value proposition. Community members report buying old early-2000s boxes on Reverb and upgrading them to current specs for around $600, making it one of the most cost-effective paths to high-end conversion.
- For Atmos setups, you can chain up to 128 boxes over Ethernet, though each box provides 8 analog outputs. For a full 7.1.4 bed you need at minimum two boxes.
- Monitor through the DAW at low buffer rather than using onboard monitoring, paired with zero-latency plugins, for the most flexible workflow.
Comparable Alternatives
| Unit | How It Compares |
|---|---|
| RME UCX II/UFX III | RME offers marginally lower latency and TotalMix FX is more mature for routing. Metric Halo offers superior DSP, the 3d upgrade path, and arguably better long-term value. Both are frequently recommended together as top-tier options. |
| Lynx Aurora (n) | Lynx is cheaper for Atmos (16 channels in one box vs. needing two MH boxes) and has integrated speaker management. Bryan DiMaio chose Lynx initially for cost but later moved to MH for features and flexibility. |
| Universal Audio Apollo | Apollo is easier to learn and more widely known, but Metric Halo offers better conversion, lower latency, no plugin lock-in, and dramatically better longevity. Several community members describe leaving UA for MH as a one-way trip. |
| Apogee Symphony II | Both offer excellent conversion. Metric Halo wins on DSP, networking, and the 3d upgrade program. Apogee has simpler software and tighter macOS integration. |
Common Mistakes
- Underestimating the learning curve. Bryan DiMaio explicitly notes he does not blanket-recommend Metric Halo to everyone because the software and configuration have a steeper learning curve than Apollo or RME. Budget time for setup and learning.
- Expecting a hardware volume knob or remote out of the box. Unlike Apollo or RME with the ARC, Metric Halo requires pairing with an external MIDI controller, Stream Deck, or EUCON surface for physical monitor control.
- Overlooking the used market. The 3d upgrade program means that a used ULN-2 or LIO-8 from years ago can be brought to current specifications. Hunting on Reverb for older units is a well-known strategy in the community.
- Assuming the 8-channel limit per box is restrictive. While each box has 8 analog outputs, the Ethernet chaining allows massive expansion. Studios have built elaborate shared analog hardware routing systems between multiple Metric Halo units across rooms.
See Also
Source Discussions
Discord Source
Channel: gear-talk Date: 2024-07 through 2025-08 Key contributors: hyanrarvey, Bryan DiMaio, Iwan Morgan, Nomograph Mastering, Ed Sokolowski, Ross Fortune, Tristan, Will Trotman, Zack Hames