Sennheiser HD 400 PRO – Open-Back Studio Reference Headphones

The HD 400 PRO offers neutral, transparent sound in a lightweight package, built for serious mixing and monitoring. With angled drivers, velour pads, and interchangeable cables, it delivers clarity, comfort, and flexibility for long studio sessions.

Key Features

• Dynamic open-back design: Produces an airy, spacious soundstage for reference listening
• Angled transducers: Optimise stereo imaging and reduce distortion at high sound pressure levels
• 120 Ω impedance: Designed for professional sources, with headroom for detailed listening
• Frequency response 6 Hz – 38 kHz: Covers extended bandwidth for both low-end and subtle high frequencies
• Velour earpads & lightweight build: Offers all-day comfort with minimal fatigue (≈ 240 g without cable)
• Interchangeable cables included: 3 m coiled and 1.8 m straight cables, plus 6.3 mm adapter

Customer Benefits

HD 400 PRO gives you a clear, uncolored sonic canvas ideal for critical listening, mixing, and mastering. The angled drivers and open acoustic design offer a realistic spatial presentation. Its comfort and light weight make it usable for extended sessions, and by including both coiled and straight cables, it adapts to different studio setups effortlessly.

Quick Specs

• Acoustic principle: Dynamic, open-back
• Ear coupling: Circumaural (over-ear)
• Impedance: 120 Ω
• Frequency response: 6 Hz – 38 kHz (−10 dB)
• Sound pressure level (SPL): 110 dB (1 kHz / 1 V RMS)
• Total harmonic distortion (THD): < 0.05 % (1 kHz / 90 dB SPL)
• Weight (without cable): 240 g
• Included cables: 3 m coiled + 1.8 m straight (3.5 mm), plus 6.3 mm adapter

What’s in the Box

• Sennheiser HD 400 PRO headphones
• 3 m coiled cable (3.5 mm twist-lock)
• 1.8 m straight cable (3.5 mm twist-lock)
• 6.3 mm adapter
• Quick start & safety guides

Use Cases / Ideal For

Designed for producers, engineers, and audiophiles who need reliable reference headphones. Excellent for mixing, editing, mastering, and general studio monitoring where open-back accuracy matters.

Compatibility

Best suited for interfaces, DACs, and headphone amps that can comfortably drive 120 Ω loads. The included cables and adapter allow connection to a wide range of studio gear.

Pros & Cons

✅ Pros:

• Accurate, balanced sound suitable for critical listening
• Wide soundstage and natural spatial cues
• Comfortable design with velour pads and light weight
• Interchangeable cables provide flexibility

⚠️ Cons:

• Open-back design leaks sound and offers minimal isolation
• Requires quality amplification for full low-frequency control
• No carrying case included

The Sennheiser HD 400 PRO strikes a fine balance between accuracy, comfort, and usability. It’s a smart choice for anyone seeking dependable reference headphones for studio and creative work.