Published On: May 27, 2015

PSB Introduces Innovative M4U 4 In-Ear Monitor

Published On: May 27, 2015
Last Updated on: October 31, 2020
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PSB Introduces Innovative M4U 4 In-Ear Monitor

PSB has introduced its first in-ear monitor, the M4U 4, due out in June. This $299, two-way in-ear monitor combines a moving coil dynamic low-frequency driver and a balanced armature high-frequency driver. Three sizes of soft inserts are included, as are...

PSB Introduces Innovative M4U 4 In-Ear Monitor

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PSB-M4U4.jpgPSB has introduced its first in-ear monitor, the M4U 4, due out in June. This $299, two-way in-ear monitor combines a moving coil dynamic low-frequency driver and a balanced armature high-frequency driver. Three sizes of soft inserts are included, as are two tangle-free cords, one of which has a microphone and telephone controls. The M4U 4 is available in a Black Diamond or Arctic White finish.

From PSB Speakers
PSB Speakers announced their newest headphone, the In-Ear Monitor M4U 4. This unique, two-way hybrid design is the company's first IEM and features a moving coil dynamic low frequency driver and a balanced armature high frequency driver controlled by a precision crossover network. The PSB M4U 4 ($299 MSRP) comes in choice of Black Diamond or Arctic White finishes and will be shipping in June, 2015.

PSB Performance
The M4U 4 incorporates balanced armature drivers with very low moving mass making them ideal for reproducing high frequencies with great transient response and detail. Musical textures are finely wrought, bringing great insight into the music and clearly delineating individual instruments and their unique voices. The precision BA driver used in the M4U 4 is individually calibrated to meet the exacting response tolerances of this In-Ear-Monitor. A wave-guide is used to link the sound tube of the BA driver to the woofer, creating time-aligned driver integration. A miniature PCB using surface mount parts creates the electrical crossover network that divides the signal between drivers.

The moving coil dynamic woofer is no less unique, tuned for accurate response with three separate chambers, creating an aperiodic loading that smooth's response and suppresses resonances. The result is deep, deep bass response that is punchy and crisp without sounding fat or boomy.

Voiced for a flat, neutral response, the PSB M4U 4 was developed at the NRC (National Research Council of Canada) using the KEMAR dummy head testing system, with the addition of low frequency room gain that one would expect to hear with normal loudspeakers in a room. This is the same room gain compensation transfer function that was developed in the ATHENA PROJECT at NRC.

These findings have led PSB to a unique feature the company calls, "RoomFeel." RoomFeel makes music sound more natural by taking into account the effects of the room on music playback. Almost all recorded music is monitored using direct radiating loudspeakers to determine the acoustic balance for the final mix. So the transfer function PSB developed for its M4U 4 headphones takes into account the "room gain" that occurs when playing direct radiator loudspeakers in a room. The result is a much richer, more immersive and more natural listening experience.

Comfort and Ergonomics
The M4U 4 was ergonomically designed to be comfortable even when worn for long periods of time. Comfort was paramount in the M4U 4's development, which led to several useful features. First of all, the cord is detachable, and the IEM's are reversible. The user has a choice of looping the cord over and behind their ear, or they can swap the left for right color-coded cord to allow the cord to drop down in front of the ear.

Three sizes of soft inserts are included to fit any size ear canal, and two types are provided; soft silicone and Comply Foam with wax guards. Comply foam is extremely comfortable, precisely fitting the individual ear canal and forming an air-tight seal that blocks outside noise and provides amazing bass extension. Silicone tips are also comfortable and can be cleaned and reused indefinitely.

Convenience and Ease of Use
The M4U 4 can be easily stored and transported in a semi-hard travel case. The M4U 4 features a unique detachable cord with a removable shirt clip. Two tangle-free cords are supplied; one is made for iPhone with convenient microphone and telephone controls. Also supplied are a 1/4 inch adaptor and a dual 1/8 inch airplane adaptor.

Key Features of the PSB M4U 4:
• Two-way hybrid design with Moving Coil Dynamic LF Driver
• Balanced Armature HF Driver
• Precision Crossover Network
• RoomFeel for immersive, lifelike experience
• Two tangle-free cords supplied, one made for iPhone certified
• Unique detachable cord design with removable shirt clip
• Comes supplied with Silicone and Comply Foam Ear Tips in small, medium and large
• Comes supplied with travel case, ¼" stereo and 1/8" dual input flight adaptors

Additional Resources
PSB Introduces Compact SubSeries 150 Subwoofer at
PSB Imagine X Speaker System Reviewed at

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