Overview

The Amber i4 is a 24-bit/192 kHz USB-C desktop interface providing 4×4 analog I/O, two Class-A mic preamps, independent 48 V phantom power, two auto-detect bidirectional MIDI ports, and dual headphone monitoring via OUTPUT A/B selection on the front panel [1][2]. Its LCD shows level meters and mode status, and the large amber main encoder controls the selected output bus. ESI’s ADM (Advanced Direct Monitoring) enables latency-free hardware mixes directly on the unit or from the Amber i4 Control app, with virtual channels & loopback for streaming/recording computer audio [1][2]. The unit is USB class-compliant (CoreAudio on macOS/iOS) and offers EWDM ASIO drivers for Windows (ASIO 2.0 / WDM / MME / DirectSound) [2]. The package includes Bitwig Studio 8-Track, Steinberg WaveLab LE, and Cubasis LE registration, plus both USB-C↔C and USB-A↔C cables in the box [2]. ESI publishes 115 dB(A) dynamic range for D/A (and 115 dB(A) class for the converters overall) [1][2].

Connections & Controls (from manual)

• Front: 2× XLR/TRS combo inputs (Mic/Line/Hi-Z), per-input GAIN, 48 V switches, LCD, SELECT / MONITORING / MIX / OUTPUT A/B keys, main encoder [2].
• Rear: LINE OUT A (1/2) & B (3/4) TRS, MIDI IN/OUT 1–2 (each bidirectional; can be configured as IN or OUT), USB-C, Power switch, optional 5 V DC input [2].
• Software: Amber i4 Control with firmware update, sample-rate and device settings, ADM mixer, and loopback routing. A third “DAW-Control” MIDI port is reserved for hardware–software comms and should be disabled in DAWs [2].

Scientific Validity

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There are no independent laboratory measurements for Amber i4’s converters/preamps at this time. ESI’s documentation provides concrete figures—115 dB(A) DR and low THD+N—which, if achieved, reach transparent performance targets for typical music production [1][2]. Per our scoring method when independent data are missing, we start at 0.5 and adjust slightly for specific, consistent manufacturer metrics, resulting in 0.6.

Technology Level

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Feature set is contemporary: 24-bit/192 kHz, Class-A pres, ADM hardware mixing, virtual channels/loopback, bidirectional MIDI, dual-bus headphone monitoring, and class-compliant operation with dedicated Windows drivers [1][2]. The manual and product page do not disclose converter chipset models or special proprietary DSP beyond ADM; thus we consider the implementation technically solid but not uniquely innovative.

Cost-Performance

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Typical street price is ≈ 240 USD for Amber i4 [5][1]. For comparison against the cheapest product with equal or better verified measurement performance, the MOTU M4 is a well-measured 4×4 interface with independently reported ≈120 dB output dynamic range and excellent loopback results [3]. In the US, M4 commonly sells for 269.95 USD at major retailers [4][6]. We did not find a cheaper interface with independent measurements meeting or exceeding the Amber i4’s 115 dB(A) class published spec. Therefore, Amber i4 is currently the lowest-cost option at this performance tier, earning 1.0.

Anchor comparison

• Amber i4 — ~240 USD, published 115 dB(A) DR, ADM/loopback, bidirectional MIDI [1][2][5].
• MOTU M4 — 269.95 USD, independent measurements ≈120 dB DR, widely validated performance [3][4][6].

Reliability & Support

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ESI offers standard warranty and actively maintains drivers/firmware via the Amber i4 Control app; documentation notes firmware update prompts and platform support (Windows 10/11; macOS 10.13+ incl. Apple Silicon) [2]. A knowledge-base entry clarifies single-unit per computer usage for Amber series (i1/i2/i4) [7]. With no public MTBF/failure-rate datasets and a smaller global service network than tier-one brands, we assess reliability/support as average.

Rationality of Design Philosophy

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The design prioritizes transparent capture, hands-on monitoring (ADM), streaming-oriented loopback, and MIDI flexibility (two auto-detect ports) in a small, bus-powered chassis with dual output buses for control-room/headphone workflows—an internally consistent, practical focus for creators on a budget [1][2].

Advice

If you want a budget 4×4 with dual-bus monitoring, loopback, and MIDI that integrates cleanly on Windows/macOS/iOS, Amber i4 is compelling. If you require independently verified top-tier measurements, the MOTU M4 remains the safe benchmark—at a higher price [3][4][6]. For cost-sensitive buyers comfortable with manufacturer-published specs, Amber i4 offers excellent value.

References

[1] ESI — Amber i4 product page: https://www.esi-audio.com/products/amberi4/
[2] ESI — Amber i4 User Manual (PDF): https://download.esi-audiotechnik.com/download/ESI/Amber_i4/Amber_i4-English.pdf
[3] Audio Science Review — MOTU M4 measurements: https://www.audiosciencereview.com/forum/index.php?threads/motu-m4-audio-interface-review.15757/
[4] B&H — MOTU M4 price: https://www.bhphotovideo.com/c/product/1514483-REG/motu_3140_m4_4x4_usb_c_audio.html
[5] Thomann — Amber i4 listing (typical street): https://www.thomannmusic.com/esi_amber_i4.htm
[6] Sweetwater — MOTU M4 price: https://www.sweetwater.com/store/detail/M4–motu-m4-4x4-usb-c-audio-interface
[7] ESI Knowledge Base — Using more than one Amber i1/i2/i4: https://download.esi-audiotechnik.com/tools/readme.asp?file=KB00338EN&key=lywp%3C03%7Czw0fwn653%2Fhj2d%7Boerlc1gev2pfg2fvpAhsyr%3DMC4563%3AFR

(2025.10.6)