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The Boulder MK-III from Unity Audio is redefining expected levels of sonic performance and accuracy for this truly world-class monitoring system.


Like the critically acclaimed MK-I & MK-II, the new MK-III boast's a fast, accurate detailed sound and prodigious extended bass response, and delivers even greater levels of SPL to fit into any critical listening environment or scenario.

Crystal Membrane 8.5" / 220mm Woofers

The eye-catching surface of the precision built German Crystal Membrane is more than just an attractive design feature. The Crystal Membrane woofer construction uses Aluminum-Sandwich AS Technology. The crystal-shaped inverse aluminium dome is joined to the paper cone in a special gluing process to result in the desired sandwich construction. Resembling the surface of a large crystal, the aluminium-foil stamping stiffens the aluminium dome, diminishing resonances and minimizing coloration, while improving power handling and dynamics.


The voice coil design of the bass drivers results in an expanded range of the respective drivers by nearly an octave. The wide, double-asymmetrical rubber surround of the 220m woofer can handle up to ±20 mm excursions for truly prodigious volume and lowest distortion, a unique engineering achievement for a driver of its size.

Amplification - Class D & Class A/B with two separate power supplies

Regarded as easily rivalling many larger and more costly monitoring systems, the new MK-III is now fitted with 2 x 300 watt Class D amplifiers with their own separate power supply specifically for the 2 x Crystal Membrane woofers. The Boulder MK-III still retains it's two original discrete custom Class A/B amplifiers with their own dedicated power supply for the Coaxial X-Jet mid-range/ribbon tweeter.With the power delivery of the two large Class D amplifiers running the two 8.5" woofers alongside the custom Class A/B amplifier for the Coaxial X-Jet mid-tweeter, the Boulder delivers a life-like sense of scale and take any performance in their stride offering high SPL figures with incredible effortless dynamics and transients.

X-JET Coaxial Mid-Range & Folded Ribbon Tweeter Drive Unit

The unique and exclusive centrally mounted Coaxial unit which is hand built in Germany comprises of a 5" ring mid-range drive unit and a centrally mounted JET5 50 kHz folded ribbon tweeter. The combination provides a reduced stray magnetic field with higher efficiency, improved dynamics and smooth, even frequency dispersion.


This compact design assures true point source phase accurate delivery across it's entire frequency spectrum from 694 Hz to 50 kHz, eliminating phase rotation and frequency anomalies. The result is exceptional imaging and detail, significantly improved impulse and power control providing much improved dynamic range and an even frequency response and dispersion throughout the listening space.

The X JET driver can be described as dynamic and detailed with depth and spaciousness over a broad listening area providing exceptional detail to beyond 50kHz.

JET 5 Folded Ribbon Tweeter

This concentrically located JET5 ribbon tweeter uses a unique folded ribbon technology providing a wide, smooth dispersion and a flat frequency response exceeding 50kHz.The precision German built JET 5 tweeter, which is also used in the Mini-Rock and The Rock has been highly regarded for years due to its superior impulse control, smooth sound character and incredible detail. Delivering true high-definition sound, the JET 5 tweeter enthrals with its lightning-fast response and wide dynamic range, offering minimal distortion, lots of headroom and a distinctly wider frequency range than conventional dome tweeters. The ELAC JET tweeter is one of the most legendary tweeters in the industry and has won international praise with its transparent and effortless sound image.


The JET tweeter was developed to perfection on the basis of the famous Air Motion Transformer by loudspeaker pioneer Dr. Oskar Heil. Its operating principle is based on a concertinaed-foil membrane, driven by a strong magnet system of neodymium rods. This motor drives the air considerably faster than the pistonic motion of a conventional driver, with gains in higher sensitivity and extraordinary dynamics. Due to many additional design changes, like an improved new neodymium magnet system, even higher efficiency, higher sound pressure levels and frequency response up to 50 kHz was achieved.


The core of the JET tweeter is the folded foil membrane. With a fold width of only 0.84 mm, a major requirement in the JET production is precision. To guarantee repeated accuracy and unchanging quality even with high production capacity, gluing and handling are now executed by two SCARA robots. The folding and fixing of the membrane, however, are executed by hand, since for production steps requiring extreme precision, the manual dexterity of skilled technicians is irreplaceable. Due to continuous improvement, the JET 5 tweeter creates an effortless, airy and resonance-free image up to 50,000 Hz, and with its linear frequency response is ideally suited for the reproduction of DVD-A and SACD.

Sealed Cabinet DesignAccurate Bass Reproduction

Like all Unity Audio monitors, the cabinet is a sealed enclosure that doesn't rely on a traditional resonate port to deliver low bass frequencies. The advantage of this design philosophy is more accurate bass with better time domain performance and a gradual 12dB per octave roll off as opposed to a 24dB roll off with ported designs.

Superior Transient Response

This approach also guaranties super fast transient reproduction far quicker than conventional ported enclosures allowing the user to hear every detail of a sounds initial attack making decisions about compressor envelopes far easier to judge.

Accurate Frequency Response At Any Level

Another invaluable attribute of the sealed cabinet design is the ability to monitor at extremely low levels without compromising low frequency reproduction which is an issue with other types of cabinet designs. No longer does the user have to monitor at higher monitoring levels to judge the bass correctly. Working for long periods of time at low to moderate listening levels while maintaining a full and accurate picture is all possible with the Boulder MK-III.

Cabinet Construction

To accommodate the large 220mm woofers the sealed cabinet uses 18mm Baltic Birch plywood and a huge 30mm Corian front baffle with large radius edges to reduce reflection and cabinet resonances. This adds density, mass and rigidity providing a solid and resonant free mounting platform for all the drive units.

DSP Version

This high performance Mac and PC compatible 24bit/96k Burr Brown converter design offers a huge amount of DSP control for the user with precise 1/10th dB level control on the input channel and output channels , mute, phase, delay and 8 bands of fully parametric EQ including various filter types, limiter protection. Plenty of factory and user presets are included such as full 3 way crossover integration for the Unity Audio Avalanche sub-woofer and B.A.B.E (Boulder Active Bass Extender).


Ther New MK-III Features

2 x New 8.5" / 220mm Crystal Membrane Woofers.

2 x New 300 watt Class D amplifiers inc dedicated PSU for woofers.

Unity Audio The Boulder MK-III 3-Way Active Monitor (Single)

  • Unity Audio The Boulder MK-III
  • 3-Way Active Monitor
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