# What are the Firewire audio interfaces with the lowest latency? — Verified Specification Comparison

> All specification data verified from official manufacturer documentation.

What are the Firewire audio interfaces with the lowest latency?

## Products

### Metric Halo Labs Mobile I/O ULN-2 Expanded
```yaml
product: metric-halo-labs-mobile-i-o-uln-2-expanded
brand: Metric Halo Labs
price_gbp: 875.33
origin_country: null
confidence_score: null
summary_source: generated_from_verified_specs_v1
latency: near-zero (mixer-based)
bit_depth: 24-bit
i_o_count: 4 inputs, 6 outputs
sample_rate: 96 kHz
phantom_power: 48V
number_of_preamps: 2
```

- **Price:** £875.33 [^1]
- **Summary:** The ULN-2 Expanded is a FireWire professional audio interface offering 4 simultaneous inputs and 6 outputs with high-quality 24-bit/96 kHz converters, two ultra-low-noise mic preamps, ADAT expansion and an onboard low-latency mixer and DSP. It supports bus or external power, word clock and multiple digital I/O formats, making it suitable for mobile and studio use.
- **Ideal For:** Suited for lowest-latency FireWire setups because it provides an onboard near-zero-latency multibus mixer for direct monitoring combined with 24-bit/96 kHz converters and low-noise preamps.
- **Additional Sources:** [^2]

### MOTU Traveler MK3 FireWire
```yaml
product: motu-traveler-mk3-firewire
brand: MOTU
price_gbp: 632.47
origin_country: null
confidence_score: null
summary_source: generated_from_verified_specs_v1
bit_depth: 24-bit
i_o_count: 28 inputs / 30 outputs (at 44.1/48 kHz)
sample_rate: Up to 192 kHz
phantom_power: Individual 48V on each mic input
number_of_preamps: 4
```

- **Price:** £632.47 [^3]
- **Summary:** Portable FireWire audio interface with four combo mic/hi-Z inputs, 8 analog outputs, extensive digital I/O (ADAT, AES/EBU, S/PDIF), CueMix FX DSP mixing and optional battery operation-suited for mobile recording and studio use. It supports high-resolution recording up to 192 kHz and standalone operation with front-panel control.
- **Ideal For:** It suits lowest-latency FireWire interface searches because it provides onboard CueMix FX DSP mixing (hardware monitoring) and FireWire connectivity, minimizing host round-trip latency.
- **Additional Sources:** [^4], [^5]

### Universal Audio Apollo 8 (FireWire via legacy interfaces or adapters)
```yaml
product: universal-audio-apollo-8-firewire-via-legacy-interfaces-or-adapters
brand: Universal Audio
price_gbp: 1489.18
origin_country: null
confidence_score: null
summary_source: generated_from_verified_specs_v1
latency: 1.1 ms
bit_depth: 24-bit
i_o_count: 18 x 24
sample_rate: 192 kHz
phantom_power: +48V
number_of_preamps: 4
```

- **Price:** £1489.18 [^6]
- **Summary:** Rackmount 18-in / 24-out Apollo with four Unison-enabled mic preamps, onboard UAD DSP for realtime plug-ins, and high-quality 24-bit/192 kHz conversion. Suits project and professional studios that need low-latency realtime processing and multiple analog I/O in a single unit.
- **Ideal For:** Well suited for lowest-latency FireWire interfaces because it offers sub-2ms realtime UAD processing and an analog round-trip latency of 1.1 ms at 96 kHz (FireWire connection) which is among the lowest for FireWire-equipped units.
- **Additional Sources:** [^7]

---
## References & Sources
[^1]: Music Store Professional, accessed 2026-06-15. https://www.musicstore.com/en_US/USD/Metric-Halo-Labs-Mobile-I-O-ULN-2-Expanded/art-PCM0008149-000
[^2]: Metric Halo (product page), accessed 2026-06-15. http://www.mhlabs.com/metric_halo/products/mio/uln2/
[^3]: Markertek, accessed 2026-06-15. https://www.markertek.com/product/motu-travelermk3/motu-traveler-mk3-firewire-digital-audio-workstation-mac-and-windows
[^4]: Guitar Center, accessed 2026-06-15. https://www.guitarcenter.com/MOTU/Traveler-mk3-FireWire-Audio-Interface-1274034484332.gc
[^5]: RK Audio, accessed 2026-06-15. https://www.rkaudio.com/motu-traveler-mk3-28x38-firewire-audio-interface..html
[^6]: Guitar Center, accessed 2026-06-15. https://www.guitarcenter.com/Universal-Audio/Apollo-Interface-18x24-FireWire-Audio-Interface-w-UAD-2-DUO-DSP-Thunderbolt-I-O-Option-Bay-1326304997010.gc
[^7]: Music Store Professional, accessed 2026-06-15. https://www.musicstore.com/en_US/USD/Universal-Audio-Apollo-8-Quad/art-PCM0013686-000