Overview

The Sennheiser HD600 is an open-back dynamic headphone released in 1997 that has been used as a reference in the professional audio industry for many years. With its high impedance design of 300Ω and excellent measured performance, it has been recognized as an acoustically superior design for over a quarter-century. It continues to be beloved by many studios and engineers today, and its design philosophy aimed at neutral and accurate sound reproduction maintains its value across generations.

Scientific Validity

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The HD600 demonstrates excellent measured performance. THD (Total Harmonic Distortion) is maintained below 0.1% across the 100Hz-20kHz range, with third-order harmonics well below audible thresholds. The frequency response achieves a flat characteristic of ±1.5dB across the 20Hz-20kHz range, approaching the transparent level (±0.5dB) in the measurement criteria. S/N ratio is above 105dB, and crosstalk is below -70dB. Sensitivity is 97dB SPL (1kHz), and the 300Ω high impedance design delivers stable performance when properly driven by appropriate amplifiers. Third-party measurements from ASR and Stereophile consistently confirm excellent measured results, making this a product with scientifically audible sound quality improvement effects.

Technology Level

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The HD600, despite being a 1990s design, employed advanced dynamic driver technology for its time. The 300Ω high impedance design enhances stability against current fluctuations and was optimized for professional audio environments. However, by current standards, it has fallen behind technological innovations such as planar magnetic drivers, modern DSP technology, and new material utilization. While the design completion is high and measured performance excellent, it remains conservative from an industry technology perspective, with limited technical innovation.

Cost-Performance

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The HD600’s current market price is 325 USD (Amazon US, August 2025). As a competitive product with equivalent performance, the HD560S from the same company is available for 154 USD. The HD560S features 120Ω impedance, 0.05% THD or below (1kHz/90dB SPL), and 20Hz-20kHz frequency response ±2dB, with S/N ratio above 105dB, and professional reviews confirming acoustic characteristics extremely close to the HD600. Calculation: 154 USD ÷ 325 USD = 0.474, which rounds to 0.5. The HD560S is technically newer and offers advantages in driving ease, making the HD600’s cost-performance average in terms of pure performance-to-price ratio.

Reliability & Support

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Sennheiser is a German audio manufacturer with over 75 years of history, maintaining high reliability standards in the industry. The HD600 has been in continuous production for over a quarter-century since its 1997 release, demonstrating a long-term product supply track record. Repair services and parts supply continue, supporting long-term use in professional applications. While the consumer business transferred to Sonova in 2021, product support continues. The warranty period is industry-standard, and failure rates are within typical ranges.

Rationality of Design Philosophy

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The HD600’s design philosophy is scientifically rational. The 300Ω high impedance design was optimized for 1990s professional audio environments, and the design premise of stable operation with dedicated amplifiers is reasonable. The tuning aimed at neutral and accurate sound reproduction is supported by measurement results, representing a rational approach that doesn’t rely on subjective or unscientific claims. The open-back design for natural soundstage reproduction is also acoustically appropriate. However, there is room for improvement in terms of modern efficiency improvements such as low-power driving and new material adoption.

Advice

The HD600 is a high-quality headphone with excellent measured performance, but at the current price of 325 USD, it cannot be actively recommended. The HD560S, which offers equivalent acoustic characteristics, is available for 154 USD and is more practical with easier driving requirements. The HD600’s value proposition is limited to cases where professional environment track record or long-term supply reliability is prioritized. If budget allows and you seek the value of a reference model with a quarter-century of history, it remains an option, but for pure sound quality and cost-performance, the HD560S is a more rational choice. Configurations like smartphone+DAC cannot easily replicate the open-back soundstage, so the dedicated device rationality is maintained. In either case, using an appropriate headphone amplifier is essential.

(2025.8.5)