Overview

The AKG K701 is an open-back studio monitor headphone formerly produced by the Austrian audio equipment manufacturer AKG. It once captivated the market with its elegant design and was celebrated for its vast and delicate soundstage, earning a dedicated following among audiophiles and professionals for many years. Its distinctive sound became widely known as “the K701 sound,” and it even gained mainstream recognition after being featured in an anime series. However, this review will set aside historical reputation and brand image to provide a dispassionate assessment of its performance based on modern technical standards and measurement data.

Scientific Validity

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From a fidelity-to-the-master-recording standpoint, the AKG K701’s frequency response does not meet contemporary standards. The low-frequency range, in particular, exhibits a significant roll-off below 100Hz, resulting in a lack of deep bass reproduction, which is crucial for the foundation of music. This falls into the “problematic” category on our criteria chart. Furthermore, there is a prominent peak in the high-frequency range around 6-8kHz. While this creates a unique “brightness” and “sense of detail,” it can sound harsh on certain recordings and detracts from a natural timbre. Although the midrange is relatively flat, the significant deviations in the bass and treble lead to an overall evaluation that the sound is not faithful to the source material.

Technology Level

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The K701 incorporates AKG’s proprietary technologies, such as the “flat-wire voice coil” and “Varimotion technology.” At the time of its release, these were advanced approaches aimed at improving driver response and reducing distortion, and its design originality is commendable. The commitment to pursuing a unique sound with in-house technology, rather than assembling off-the-shelf components, is a positive aspect. However, measurement data reveals high-frequency resonance (ringing), and when compared to more sophisticated modern driver designs, its technological advantage has diminished. While it surpasses the industry average, it does not reach the highest standards.

Cost-Performance

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We will use the current market price of the K701’s successor, the K702 (approximately 140 USD), as a benchmark. As a comparison, HIFIMAN’s planar magnetic headphone, the HE400se (retailing overseas for 109 USD, approx. 115 USD), stands as one of the world’s most affordable products with equivalent or superior performance. The HE400se is noted for its superior bass extension and more natural high-frequency characteristics compared to the K701. Since a more capable and cheaper alternative exists, the cost-performance ratio is not high. Based on the formula “115 USD / 140 USD ≈ 0.819,” the score rounds to 0.8.

Reliability & Support

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While the AKG brand has a long history, the K701 has a distinct design flaw. As many users have reported, the elastic bands that adjust the headband length stretch out after a few years, making it impossible to maintain a proper fit. This is a structural defect that goes beyond normal wear and tear. Additionally, the non-detachable cable makes repairs difficult in case of a break, significantly compromising long-term reliability. Due to these issues, the rating is extremely low.

Rationality of Design Philosophy

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The design philosophy of the K701, which aims for analytical listening with a flat midrange and a wide soundstage, is rational in itself. However, the execution is questionable. Specifically, the approach of creating perceived “detail” and “air” by introducing an intentional peak in the high frequencies is irrational from a scientific standpoint of faithfully reproducing the master recording. This adds coloration not present in the original source and is inconsistent with the latest scientific consensus. Therefore, the rationality of the design philosophy must be rated as low.

Advice

The AKG K701 is a headphone still talked about for its beautiful design and the unique sound that once defined an era. It has a certain charm, especially with female vocals and string instruments. However, when evaluated as a modern audio product, its performance falls short in many areas. The lack of bass and the peak in the treble result in an unbalanced sound for most music genres, and it cannot be recommended for users seeking faithful reproduction of master recordings.

From a cost-performance perspective, numerous headphones in the same price range or lower offer a flatter frequency response and superior overall performance (e.g., HIFIMAN HE400se, Sennheiser HD 560S). Furthermore, the fatal flaw of the stretching headband elastic makes it a risky choice for long-term use.

If you wish to experience the specific sound character known as “the K701 sound,” or are attracted to its historical value and design, it might be a viable option. However, for those seeking pure acoustic performance and value for money, we strongly recommend considering other modern alternatives.

(2025.7.14)