Overview

The AKG K240 Studio is a semi-open studio monitor headphone manufactured by the Austrian company AKG. Inheriting the design of the K240 launched in 1991, it has been a standard model used in studios worldwide for over 30 years. It features 30mm XXL transducers and Varimotion diaphragms, designed specifically for professional applications. The current market price is around 42 USD, making it widely popular as a low-priced studio headphone.

Scientific Validity

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According to measurement data, the K240 Studio reaches problematic levels across multiple acoustic performance indicators. The most serious issue is Total Harmonic Distortion (THD), which increases significantly in the low frequencies, preventing faithful reproduction of the source material. This is a clear issue based on headphone evaluation criteria. The frequency response shows deviations exceeding ±3dB below 100Hz and above 5kHz, which also fails to meet the standard. Furthermore, its semi-open design results in poor noise isolation; many measurements report it below 10dB, which also constitutes a problematic level.

Technology Level

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The K240 Studio is based on a 1991 design, technically inheriting an approach from over 30 years ago. The 30mm XXL transducers and Varimotion diaphragms were advanced for their time but represent modest specifications by current technical standards. The 55-ohm impedance design considers compatibility with a wide range of equipment but offers no special technical advantage. The implementation of the semi-open structure is a conventional design approach. No innovative technologies that contribute to improved measurement performance are evident, placing it at an industry-average level of technical implementation.

Cost-Performance

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The cost-performance of the K240 Studio (around 42 USD) is evaluated by comparing it with the cheapest alternative that offers equivalent or superior performance. A suitable comparison is the Superlux HD681, another semi-open model available for around 27 USD. While the HD681 has its own performance quirks, it serves as a functional alternative, particularly given its lower price. Based on the policy, the calculation is: 27 USD ÷ 42 USD = 0.642… Rounding this result gives a score of 0.6.

Reliability & Support

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Given its 30-plus years of continuous manufacturing, the K240 Studio’s basic design reliability is considered high. However, its plastic housing and lightweight-focused construction raise concerns about long-term durability in a professional setting. The warranty is typically one year, but repair support can be limited compared to domestic brands in many regions. Considering these factors, the support system is evaluated as being near the industry’s lowest level.

Rationality of Design Philosophy

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The design philosophy of the K240 Studio has a clear rationality in its goal of providing a semi-open soundstage at a low cost. Continuing the 1991 design without major changes is a commendable strategy to minimize development costs and achieve a very affordable price point of around 42 USD. However, the decision to neglect significant measurement issues, such as the severe low-frequency distortion that could be technically improved, is an irrational aspect for an audio product aiming for fidelity. Overall, while it establishes its reason for existence, the presence of these key flaws prevents it from being fully rational.

Advice

The K240 Studio is recommended only for users who prioritize budget above all else and want to experience a semi-open soundstage affordably. However, its high harmonic distortion in the low frequencies is a significant drawback for music production or critical listening, making it unsuitable for bass-heavy genres. A cheaper semi-open alternative is the Superlux HD681 (around 27 USD). If a closed-back design is acceptable, the Audio-Technica ATH-M40x (around 67 USD) offers far superior measurement performance. When using the K240 Studio, it is crucial to understand its sonic limitations and always use it alongside a more reliable reference system.

(2025.7.21)