Overview

The ESI Amber i4 is a 24-bit/192kHz 4-in/4-out USB-C audio interface from German manufacturer ESI. It features two Class-A microphone preamps, a claimed 115dB dynamic range, and zero-latency monitoring, designed for music production and recording. It connects to modern computers via USB-C and includes MIDI ports in an all-in-one design.

Scientific Validity

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The ESI Amber i4 shows excellent performance in its published specifications. The manufacturer claims a dynamic range of 114dB for the A/D converter and 115dB for the D/A converter, with a THD+N of -100dB. These figures meet or approach the standards for “transparent” audio quality as defined by our review policy (Dynamic Range ≥ 105dB, THD ≤ 0.01%/-80dB). While comprehensive data like detailed measurement graphs are not provided—a common practice for many manufacturers—the key published metrics indicate a high level of performance. However, for a more definitive and precise assessment, independent verification by a reliable third party would be required.

Technology Level

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The ESI Amber i4 uses AKM’s AK5554VN ADC and AK4458VN DAC chips, which are solid, mid-tier components common in the industry. The inclusion of Class-A preamps, 48V phantom power, and USB-C connectivity is modern, but the design lacks any standout proprietary or advanced technology. Support for low latency down to 32 samples is standard. Overall, the technology level is average, representing a competent assembly of existing components.

Cost-Performance

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The ESI Amber i4 is priced at approximately 240 USD. Based on its 4-in/4-out configuration and claimed specifications, our research found no alternative product that is both cheaper and verifiably offers equivalent or superior performance based on reliable measurement data. While some cheaper products exist, they lack the objective evidence to confirm their performance is on par with or exceeds the Amber i4. According to our review policy, if no cheaper alternative can be found, the product receives the highest score. Therefore, as one of the most affordable options for its feature set, its cost-performance is rated at 1.0.

Reliability & Support

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ESI has a long-standing presence in the audio industry and provides basic product support, including standard warranties and firmware updates. However, their support infrastructure and global repair network are less extensive than those of major manufacturers. A lack of public data on failure rates or MTBF makes long-term reliability difficult to assess. The support is considered average for the industry.

Rationality of Design Philosophy

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The design philosophy of the ESI Amber i4 is fundamentally rational, aiming to provide a compact 4-in/4-out interface. The use of 24-bit/192kHz converters and low-noise preamps is a scientifically sound approach to achieving good audio quality. The excellent published specifications support a rational design philosophy that aims for high performance while keeping costs down. It is a rational product that balances features, performance, and cost effectively.

Advice

The ESI Amber i4 stands out as one of the most cost-effective options on the market for a 4-in/4-out audio interface. Its published specifications are excellent, making it an extremely attractive product for users who need a multi-channel setup on a budget. For those who demand proven, absolute performance, a more expensive alternative like the MOTU M4 might be considered. However, based on the provided specs, the Amber i4 offers performance that punches well above its price class, making it a very wise choice.

(2025.7.20)