New headphones designed for a detailed and honest sound
Review by Alex Hawley
Sennheiser has been a leader in the headphone space for decades. With models covering the full spectrum from consumer to pro audio to audiophile, the new HD 400 PRO headphones represent the latest flagship model in the Sennheiser Pro series—an open-back design for mixing, mastering, and music production.
The HD 400 PRO headphones are intended to provide a natural and accurate listening experience in a lightweight housing. The open cup over-ear design is optimized for providing a wide and transparent soundstage that feels closer to a studio monitor experience. While closed designs certainly have a place in professional studios, I have always found open-backs to provide a more authentic experience for mixing and longer marathon sessions without getting as fatigued.
Past Featured Reviews
- March 2024: JZ Microphones BT202
- February 2024: JH Audio Pearl + Ruby
- February 2024: Antares Vocal Reverb by Auto-Tune
- January 2024: Ableton Push 3
- December 2023: KIT Plugins BB A5
- Focal Twin6 ST6
- Earthworks SR117 & SR3117
- November 2023: AEA TRP3 and RPQ3
- October 2023: AudioScape 260VU Compressor/Limiter
- September 2023: Sound Devices MixPre-6 II
- August 2023: Soundtoys SuperPlate
- July 2023: Strymon Zelzah Multidimensional Phaser
The headphones use comfortable velour earpads with an adjustable headband for sizing. I have a larger head than most, and there was still plenty of room for a comfortable fit. I did find that it has a firm clamp, causing some pressure around the ears. While this helps maintain a tight seal, in my case it also led to taking more breaks than usual to rest the sides of my head. The housing seems durable for day-to-day studio use, but all the critical components are made of plastic, likely chosen to keep the weight down and make them more affordable.
The HD 400 PRO looks strikingly similar to the very popular HD 560S in the Sennheiser audiophile lineup. I didn’t directly compare the two, but they do have a lot in common on paper. The 5XX series has been around for a long time—the ‘S’ in HD 560S designates a brand new 120 ohm transducer. This move was an immediate success, so it’s no surprise that Sennheiser would issue a PRO model with the same transducer. It uses a specialized polymer blend in its diaphragm that improves transient response and detail above 10 kHz. The drive magnet achieves better bass extension through high power, and a damping system manages ventilation. The new transducer design brings the distortion rating down to an impressive < 0.05% THD. The frequency response is listed from 6 Hz to 38 kHz, and it ships with both coiled and straight cables along with a 1/8” to 1/4” adapter.
I have extensive experience with the Sennheiser HD 650 model in the audiophile line—in fact, I’ve used them on just about every mix I’ve done as a professional mixer. The open and detailed signature of the HD 400 PRO sounded immediately familiar. The low-frequency response is controlled, with excellent bass definition and low-mid clarity. The high frequencies have an airy brilliance but do not feel overly hyped or emphasized. Overall, I’d describe them as detailed, naturally bright, and controlled. It gives an honest representation of the mix in a way that isn’t overly mid-forward or sterilized; the music still has life and excitement, the lows still have energy and punch, and the highs have an intimate sheen. The soundstage is immersive, with superb spatial detail and definition.
Next to the industry-standard HD 6XX series, its high frequencies are a touch more present, while the mids feel slightly more pulled back by comparison.
Sennheiser has always been highly regarded for honest sound, especially with its open-back models. The new transducer builds on this trademark focus and accuracy. The response is incredibly accurate, and I didn’t have any red flags with mixes translating from the HD 400 PRO to any other speaker systems. At $249, these headphones fall into the low-price column of the pro tier, but perform in a way that far exceeds it—well suited to be your new workhorse mix reference headphones, and with a great blend of comfort and performance.
More from: en-us.sennheiser.com