RME Fireface UCX II
Professional 20-in/20-out USB interface with excellent engineering, stable low-latency drivers, and comprehensive I/O. Independent tests and official specs indicate performance at the transparency border (≈105 dB SINAD, DR 112 dB/115 dBA, THD+N <0.00063%). Cost-performance is pressured by cheaper interfaces with equal-or-better measured performance.
Overview
The Fireface UCX II is a compact half-rack 40-channel USB interface (20-in/20-out) with two mic pres, AES/EBU, ADAT, S/PDIF, word clock, MIDI, DC-coupled line outputs, TotalMix FX, DURec stand-alone recording, and Class Compliant mode up to 192 kHz. RME’s SteadyClock FS and in-house USB drivers underpin its reliability. [1][2]
Scientific Validity
\[\Large \text{0.8}\]Third-party measurements report line-out SINAD just under 105 dB (4 V RMS / 48 kHz). [4] Manufacturer technical data specify dynamic range 112 dB (115 dBA), THD+N < −104 dB (0.00063%), frequency response −0.5 dB @ 20.8 kHz (44.1 kHz), and channel separation >110 dB, all consistent with audibly transparent performance in normal use. [2] Round-trip latency reports using RTL Utility show <5 ms at 48 kHz with small buffers on Windows (system dependent). [5]
Technology Level
\[\Large \text{0.9}\]SteadyClock FS (femtosecond-class clocking), FPGA/DSP-based TotalMix FX, DURec (40-ch stand-alone recording), DC-coupled outputs, and long-lived cross-platform drivers (recent Windows USB driver updates) reflect a mature, well-integrated platform. [1][2]
Cost-Performance
\[\Large \text{0.6}\]Current market price: 1,259 USD. As the cheapest equal-or-better comparator, MOTU UltraLite-mk5 offers 18-in/22-out with ADAT I/O and a DSP mixer; independent tests show equal-or-better SINAD (~111–114 dB). [6][7]
Calculation: 729 USD ÷ 1,259 USD = 0.579 → 0.6 (rounded to one decimal). Result: the UCX II does not lead on value when equal-or-better measured performance is obtainable for substantially less.
Reliability & Support
\[\Large \text{0.9}\]RME is recognized for long driver/firmware support and stability. Updates and documentation are active; manufacturer warranty is 2 years in the US region. [1][3]
Rationality of Design Philosophy
\[\Large \text{1.0}\]The design emphasizes measurable fidelity: low-jitter clocking, flat FR, low distortion/noise, comprehensive routing/monitoring, and robust driver engineering. Investments (TotalMix FX, DURec, DC coupling) improve measurable utility rather than aesthetics. [1][2]
Advice
Choose UCX II for proven driver stability, AES/EBU plus word clock, DURec stand-alone capture, and TotalMix FX routing in a compact format. If you mainly need multichannel USB I/O with strong measured transparency and ADAT expansion, MOTU UltraLite-mk5 delivers similar audible transparency at a lower price, yielding better objective value. [6][7]
References
[1] RME, “Fireface UCX II – Product Page,” https://rme-audio.de/fireface-ucx-ii.html, accessed Aug 25, 2025.
[2] RME, “Fireface UCX II – Manual v1.3,” https://rme-audio.de/downloads/fface_ucx2_e.pdf, accessed Aug 25, 2025.
[3] RME USA, “Product Support / Warranty,” https://www.rme-usa.com/support.html, accessed Aug 25, 2025.
[4] Audio Science Review (forum), “(Unofficial) RME UCX II Interface Review and Measurements,” Sep 21, 2021, https://www.audiosciencereview.com/forum/index.php?threads/unofficial-rme-ucx-ii-interface-review-and-measurements.26755/ , accessed Aug 25, 2025.
[5] RME Forum, “Fireface UCX II Latencies,” Feb 27, 2023, https://forum.rme-audio.de/viewtopic.php?id=36957 , accessed Aug 25, 2025.
[6] Audio Science Review (forum), “MOTU UltraLite-mk5 Review (Audio Interface),” Jul 7, 2021, https://www.audiosciencereview.com/forum/index.php?threads/motu-ultralite-mk5-review-audio-interface.24777/ , accessed Aug 25, 2025.
[7] MOTU, “UltraLite-mk5 – Product Page,” https://motu.com/products/gen5/ultralite-mk5/ , accessed Aug 25, 2025.
(2025.8.25)