sE Electronics KLS-150

sE Electronics KLS 150 – Professional Closed-Back Studio Headphones with Mechanically Adjustable Acoustics

The sE Electronics KLS 150 are professional closed-back, over-ear headphones featuring a mechanically adjustable acoustic system that allows the bass response to be physically altered. Unlike headphones that rely on electronic bass adjustment, the KLS 150 use a passive acoustic solution that changes the low-frequency response mechanically within the earcup system. Combined with custom-engineered 40 mm dynamic drivers, effective passive sound isolation and a rugged construction, the KLS 150 are designed for critical monitoring, mixing, recording and professional live sound applications.

The closed-back, dual-shell earcup construction helps reduce external noise and minimise headphone bleed during recording. Premium memory foam ear pads provide comfort during extended sessions, while a detachable locking cable, swivelling earcups and reinforced components make the KLS 150 well suited to demanding professional use.

Mechanically Adjustable Acoustics – More Than a Conventional Bass Control

The most distinctive feature of the KLS 150 is their integrated Bass Control system. Rather than using conventional electronic bass enhancement or digital EQ, the headphones adjust their low-frequency response through a physical, mechanical change to the acoustic system within the earcups.

This means the adjustment changes the acoustic conditions of the headphones themselves, rather than simply altering the level of an electrical audio signal. The system operates entirely passively and requires no batteries, DSP or external software.

Separate rotary controls allow the bass response to be adjusted directly on the headphones. These controls sit beneath removable earcup covers, with clear markings that make it easier to return to a previously selected setting and maintain a consistent monitoring reference.

For audio engineers, this provides a practical way to adapt the bass presentation to different workflows. A familiar reference setting can be maintained for critical mixing, while a different low-frequency balance may be useful during tracking, monitoring or live sound work.

The removable earcup covers also protect the controls against accidental adjustment, helping to keep the selected settings in place during use and transport.

Custom-Engineered 40 mm Drivers for Detailed Monitoring

At the heart of the KLS 150 are custom-engineered 40 mm heavy-duty dynamic drivers with neodymium magnets. The drivers are designed to deliver detailed, well-balanced reproduction with controlled low frequencies and low distortion.

The specified frequency range extends from 12 Hz to 28 kHz, providing the foundation for reproducing both deep bass frequencies and fine high-frequency detail.

Controlled low-frequency reproduction is particularly important when working with bass guitars, kick drums, synth bass and other sources where accurate low-end balance is essential.

With a 39-ohm impedance, the headphones can be used with a wide range of professional audio interfaces, headphone amplifiers and other compatible audio sources.

Effective Passive Isolation with Dual-Shell Earcup Construction

The KLS 150 feature an innovative closed-back earcup design built around a dual-shell construction. This design is engineered to provide effective passive sound isolation, reducing the amount of sound passing between the headphones and the surrounding environment.

During vocal recording, the isolation helps minimise headphone bleed into open microphones. When recording acoustic instruments or other sensitive sources, reduced spill can contribute to cleaner recordings.

For FOH and monitor engineers, the same isolation is particularly useful in loud venues, helping them focus on individual signals with less interference from stage sound and audience noise.

The isolation is entirely passive and does not rely on active noise cancellation.

Comfort Designed for Long Studio Sessions

During extended recording and mixing sessions, comfort becomes an essential part of the monitoring experience. The KLS 150 feature ergonomically designed ear pads with premium memory foam that adapts to the shape of the head and helps distribute pressure evenly.

The ear pads are finished in high-quality leatherette, providing a comfortable fit while helping maintain a consistent seal around the ears. A secure seal is important for both passive isolation and predictable low-frequency reproduction.

Weighing 335 grams, the KLS 150 are designed to balance a stable fit with long-session comfort. Optional velour ear pads are also available for users who prefer an alternative material.

Rugged Construction for Studio and Touring

The KLS 150 are engineered for regular professional use in studios, on stages and on the road. Glass-fibre-reinforced components are combined with corrosion-resistant spring steel to provide mechanical strength and long-term reliability.

The detachable cable features a locking connector that helps prevent accidental disconnection during use. The earcups can swivel through 90 degrees, allowing convenient one-ear monitoring for FOH work, quick signal checks and other professional applications.

Multiple folding configurations make the headphones easier to store and transport. Laser-etched reference markings also allow users to return quickly to their preferred headband position.

Flexible Connectivity and Practical Accessories

The KLS 150 are supplied with a straight, detachable 3-metre cable and a screw-on 3.5 mm to 6.35 mm jack adaptor. A 3.5 mm to USB-C adaptor is also included for connection to compatible digital devices.

The package also includes removable earcup covers, a dedicated earcup-cover opening tool and a protective drawstring pouch.

Additional accessories, including velour ear pads, a coiled cable, protective cases and alternative earcup covers, offer further ways to customise the headphones for different professional workflows.

Key Features

• Professional closed-back over-ear headphones for studio, recording, mixing and live sound
• Mechanically adjustable acoustic system that physically changes the bass response
• Passive Bass Control without DSP, batteries or electronic EQ
• Independent bass controls with clear markings for repeatable settings
• Custom-engineered 40 mm dynamic drivers with neodymium magnets
• Frequency range of 12 Hz to 28 kHz
• Dual-shell earcup construction for effective passive sound isolation
• Premium memory foam ear pads with leatherette covering
• Removable earcup covers that protect the bass control settings
• Glass-fibre-reinforced components and corrosion-resistant spring steel
• Detachable 3-metre cable with locking connector
• 90-degree swivelling earcups for one-ear monitoring
• Foldable construction and laser-etched reference markings
• USB-C adaptor and protective drawstring pouch included

Technical Specifications

• Type: Closed-back, over-ear headphones
• Drivers: Custom-engineered 40 mm heavy-duty dynamic drivers
• Magnets: Neodymium
• Bass adjustment: Mechanical, passive acoustic Bass Control
• Earcup construction: Dual-Shell
• Frequency range: 12 Hz – 28,000 Hz
• Impedance: 39 ohms
• Sensitivity: 98 dB
• Maximum input power: 1,600 mW
• Ear pads: Memory foam with leatherette covering
• Earcup swivel: 90 degrees
• Cable: Straight, detachable 3 m cable with locking connector
• Connection: 3.5 mm jack
• Adaptors: 6.35 mm jack and USB-C
• Dimensions (L × W × H): 166 × 83 × 200 mm
• Weight: 335 g

What's in the Box

• sE Electronics KLS 150 headphones
• Removable earcup covers
• Earcup-cover opening tool
• Straight, detachable 3 m cable
• Screw-on 3.5 mm to 6.35 mm jack adaptor
• 3.5 mm to USB-C adaptor
• Protective drawstring pouch

Frequently Asked Questions About the sE Electronics KLS 150

How does the mechanical bass adjustment on the KLS 150 work?

The KLS 150 use a passive acoustic system that is adjusted mechanically on the headphones themselves. Changing the setting physically alters the acoustic conditions affecting the bass response. This is an acoustic adjustment rather than digital EQ or electronic bass enhancement.

Do the KLS 150 have a physically adjustable acoustic chamber?

The KLS 150 feature a mechanically adjustable acoustic system within the earcups that physically changes the bass response. The manufacturer does not specify the precise internal mechanism in detail.

Does the bass adjustment require batteries or software?

No. The Bass Control system operates entirely mechanically and passively, without batteries, DSP or software.

Are the KLS 150 suitable for professional mixing?

Yes. The KLS 150 are designed for critical monitoring and mixing. Their custom-engineered 40 mm drivers and mechanical bass adjustment allow engineers to establish and maintain a consistent listening reference.

Are the KLS 150 suitable for vocal recording?

Yes. The closed-back Dual-Shell construction provides effective passive sound isolation and helps reduce headphone bleed into microphones during recording.

Do the KLS 150 feature active noise cancellation?

No. The KLS 150 rely on passive sound isolation provided by their closed-back, dual-shell earcup construction and sealing ear pads.

Can the KLS 150 be used for FOH and live monitoring?

Yes. The KLS 150 are designed for professional live sound applications. Their passive isolation, rugged construction and 90-degree swivelling earcups make them suitable for FOH and monitor engineers.

What accessories are included with the KLS 150?

The headphones include a straight 3-metre cable, a screw-on 3.5 mm to 6.35 mm jack adaptor, a USB-C adaptor, removable earcup covers, an opening tool and a protective drawstring pouch.