Overview

The MOTU M4 is a 4-input, 4-output USB-C audio interface positioned in the entry-level professional market. Released as part of MOTU’s M-series, it features ESS Sabre32 Ultra DAC technology and delivers a manufacturer-measured 120 dB dynamic range on the main outputs with 24-bit/192 kHz resolution [2]. It includes a full-color LCD for comprehensive metering and achieves an ultra-low 2.5 ms round-trip latency at 96 kHz/32-sample buffer (manufacturer measurement) [2]. Mic preamp EIN is specified at -129 dBu (manufacturer) [2]. These measurements and features establish it as a measurement-focused solution in the competitive sub-300 USD audio interface segment.

Scientific Validity

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Manufacturer measurements indicate 120 dB output dynamic range, -129 dBu EIN on mic inputs, and 2.5 ms round-trip latency at 96 kHz/32-sample buffer [2]. Independent testing (Audio Science Review) confirms transparent-class performance across core metrics (dynamic range/SINAD, THD+N/IMD) consistent with high-fidelity thresholds defined in this site’s criteria [1]. Overall, measured performance clears transparent thresholds for dynamic range (≥105 dB) and distortion (≤0.01% THD+N equivalent) with comfortable margin, supporting a high scientific validity score.

Technology Level

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The M4 incorporates ESS Sabre32 Ultra DAC technology, representing industry-standard high-performance conversion typically reserved for premium interfaces. The full-color LCD display providing real-time level metering for all inputs and outputs demonstrates advanced implementation uncommon in this price category. Ultra-low 2.5ms latency achievement at 96kHz with 32-sample buffer indicates sophisticated driver optimization. DC-coupled outputs enable modular synthesizer integration, while hardware monitoring provides zero-latency operation. The combination of premium converter technology with thoughtful feature implementation elevates the design above typical entry-level offerings.

Cost-Performance

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Current US market price: 269.95 USD (B&H) for M4 [3]. As a like-for-like comparator, Focusrite Scarlett 4i4 4th Gen is 299.99 USD (B&H) with comparable user-facing functions (4x4 I/O, MIDI, 24-bit/192 kHz) [4]. We could not identify any cheaper current-production interface that matches the M4’s measured transparent-class performance (dynamic range/distortion) and equivalent functions. Therefore, the M4 is the cheapest equivalent-or-better option at this time, and CP is set to 1.0.

Reliability & Support

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MOTU maintains established market presence with consistent driver updates supporting Windows, macOS, and iOS platforms. Standard warranty coverage and technical support infrastructure meet industry norms. Regular compatibility updates demonstrate ongoing development support. No significant reliability issues reported in user feedback or professional reviews. The company’s long-standing presence in professional audio provides confidence in continued support, though specific reliability metrics and MTBF data are not publicly available.

Rationality of Design Philosophy

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Design philosophy prioritizes measurable audio performance through ESS Sabre32 Ultra converter selection, achieving transparent-level specifications at entry-level pricing. LCD metering implementation provides objective visual feedback supporting measurement-based monitoring practices. Hardware monitoring eliminates software-induced latency for direct monitoring scenarios. The focus on quantifiable performance improvements over subjective enhancement features reflects scientifically rational development priorities. Software bundle includes practical tools without excessive marketing-driven additions.

Advice

The MOTU M4 represents optimal selection for users requiring 4x4 I/O with emphasis on measured audio quality and comprehensive monitoring capabilities. The ESS Sabre32 Ultra DACs deliver performance typically associated with interfaces costing 2–3x more, while LCD metering provides professional-grade visual feedback uncommon in this price range. Users prioritizing maximum headphone output should verify level requirements relative to their headphones. For recording applications prioritizing objective audio quality over subjective character, the M4 offers exceptional value through measurement-verified performance.

References

[1] Audio Science Review, “Motu M4 Audio Interface Review”, https://www.audiosciencereview.com/forum/index.php?threads/motu-m4-audio-interface-review.15757/ (accessed 2025-08-11)

[2] MOTU, “M4

MOTU.com”, https://motu.com/en-us/products/m-series/m4/ (accessed 2025-08-11)

[3] B&H Photo, “MOTU M4 USB-C Audio-MIDI Interface”, https://www.bhphotovideo.com/c/product/1514483-REG/motu_3140_m4_4x4_usb_c_audio.html (accessed 2025-08-11)

[4] B&H Photo, “Focusrite Scarlett 4i4 USB-C Audio/MIDI Interface (4th Generation)”, https://www.bhphotovideo.com/c/product/1779668-REG/focusrite_scarlett_4i4_4g_scarlett_4i4_4th.html (accessed 2025-08-11)

(2025.8.11)