What are the Firewire audio interfaces with the lowest latency?

Product ⇅ Price ⇅ I/O Count ⇅ Sample Rate (Hz) ⇅ Bit Depth (bits) ⇅ Latency (ms) ⇅ Number of Preamps ⇅ Phantom Power ⇅
Metric Halo Labs Mobile I/O ULN-2 Expanded
US 		£875.33 ≈ 4 inputs, 6 outputs 96 kHz 24-bit near-zero (mixer-based) 2 ✓

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.

Sources:
Music Store Professional Metric Halo (product page)
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MOTU Traveler MK3 FireWire
US 		£632.47 ≈ 28 inputs / 30 outputs (at 44.1/48 kHz) Up to 192 kHz 24-bit — 4 ✓

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.

Sources:
Markertek Guitar Center RK Audio
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Universal Audio Apollo 8 (FireWire via legacy interfaces or adapters)
US 		£1489.18 ≈ 18 x 24 192 kHz 24-bit 1.1 ms 4 ✓

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.

Sources:
Guitar Center Music Store Professional
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