Superlux HD667

Built for maximum isolation

Few headphones match the Superlux HD667 when it comes to blocking out external noise. Its uncompromisingly secure fit is achieved at a cost: the clamping force is the strongest we’ve measured in almost a decade of headphone testing. While the padded headband and ear cushions provide comfort for a while, users will need to take breaks during extended sessions.

The 180° swivelling ear cups make the Superlux HD667 suitable for DJ monitoring as well, though its cable routing poses a flaw. The audio cable runs loosely through the headband and can slip out when the cups are rotated – an issue the manufacturer would do well to address. If improved, the HD667 would be a nearly perfect specialised tool for drummers, DJs and FOH technicians in need of extreme isolation.

Package contents

The Superlux HD667 comes with a practical two-metre detachable cable terminated with a 3.5 mm mini-jack, plus a screw-on 6.35 mm adapter. All connectors are gold-plated to resist corrosion and ensure reliable conductivity. A volume control is integrated into the cable via a small wheel – handy during live shows or recording sessions. Also included is a simple velvet drawstring pouch for transport. Overall, the accessories are well thought out and usable.

Design and construction

Clad in simple black, the Superlux HD667’s design is functional rather than flashy. A generously padded headband aids comfort, while the leatherette earpads seal tightly to maximise isolation. The closed-back ear cups are built as a single moulded piece, reducing potential leakage both in and out.

The headband’s size adjustment uses sliding arms to extend the cups. The standout (and not entirely positive) detail is the cable routing: unlike the HD665, the HD667 leaves the inter-cup cable exposed in the headband, which feels fragile for stage use.

Technical specifications

Inside are 40 mm dynamic drivers with neodymium magnets, offering a frequency range from 10 Hz to 20 kHz – extending lower than human hearing to deliver powerful sub-bass. Sensitivity measured at 101.53 dB SPL makes for robust output, which, combined with the isolation, cuts through loud environments.

With a measured impedance of 39 ohms, the Superlux HD667 runs easily from laptops, portable devices and low-powered headphone outputs – ideal for mobile monitoring.

Handling and ergonomics

The cable attaches on one side with a twist-lock connector, providing security during live use. The ear cups swivel 180° for one-ear monitoring, but as noted, this movement often dislodges the loose headband cable. The headphone also folds for transport, saving space in a gig bag.

At 342 g (without cable), the Superlux HD667 is relatively light. All the more surprising then is the extreme clamping pressure, the highest we’ve recorded in over eight years of reviews. While this ensures rock-solid stability even during rapid head movements, comfort suffers over long sessions. The integrated cable volume control is a clever touch, allowing gain staging via an external amp while the performer adjusts listening level directly.

Sound quality

Isolation is the Superlux HD667’s defining trait – outside noise is blocked with remarkable efficiency. Yet sonically, it holds its own. Sub-bass is delivered with authority, extending impressively deep before only distorting at very high levels.

The lower mids sound full and rounded, lending weight to voices and instruments. Vocal intelligibility is strong, though at higher volumes the mids are the first to show signs of distortion. Treble is present and reasonably detailed, without being overly sharp or fatiguing.

The stereo image is narrow and resolution modest, but for monitoring purposes it is entirely adequate. Dynamics are somewhat compressed, which suits its role as a live monitoring tool.

Verdict

The Superlux HD667 is a closed-back monitoring headphone that excels in one area above all others: sound isolation. It is a near-ideal choice for drummers, FOH engineers, and even DJs who demand maximum shielding from external noise. Its sound signature is bass-strong, warm in the mids and highs, and sufficiently detailed for monitoring, though not designed for hi-fi critical listening.

Its drawbacks – extreme clamping force and fragile cable routing – limit comfort and longevity, but for those who need uncompromising isolation at a very accessible price, the Superlux HD667 is a specialist’s gem.