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Monitor Audio - Radius 45 - Bookshelf Speakers

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For ultra-discreet sound all around the home, or partnered with the Radius 380 sub for explosive stereo, the miraculously small Radius 45 houses a 3" MMP II mid-bass driver and rear-firing 3/4" C-CAM tweeter, and has no right to sound as good as it does.



  • 3" MMP II Driver. All drivers are dedicated and model specific, with each model in the Radius series being designed and voiced individually.
  • 3/4" Gold C-CAM tweeter, rear-firing to enhance sound dispersion characteristics
  • Single through-bolt driver fixing. Provides mechanical de-coupling properties resulting in enhanced mid-band clarity and resolution.
  • Through-bolts also act as rigid cross bracing to give a very solid non-resonant cabinet.
  • Single point ¼" x 20TPI wall fixing. Use the optional Monitor
  • Audio speaker mount or any standard wall bracket
  • Optional floor-stand with internal (pre-wired) cable management system


Radius Overview

Great Sound With A Living Dimension

Back in the days before anyone had ever heard of ‘designer’ products and hi-fi came with wardrobe-like enclosures and racks of chunky boxes, Monitor Audio invented the Radius Series of stylish and versatile speaker systems. So radical was the idea that it changed expectations of home entertainment forever.

It seems perfectly natural for today’s audio fans to appreciate and expect a strong element of design in every product, but in 2003 it was new. Sure there existed super-chic systems, but they were also super-expensive and not considered as proper ‘hi-fi’. Radius was democratically priced, and from a respected hi-fi brand. It proved that real hi-fi could also be unashamedly stylish, space-efficient and easy to live with. In other words harmonious in every way.

From the options available, music and film lovers could choose a speaker system that not only delivered the wide natural response of a genuine Monitor Audio design, it could also match the shape and colour of their rooms. This was revolutionary. The world’s first widely available ‘designer’ speakers met with worldwide acclaim on launch, followed by repeat critical applause for subsequent upgrades, including a coveted Europe-wide EISA award in 2009.

Imbued with a rich heritage of innovation and energised by our driver technologies, this generation of Radius comes complete with more models, greater versatility and higher, wider, deeper sound. Living with great audio has never been easier.

Perfect Chemistry of Design & Performance

With its jewel-like size and lustre, Radius’ appeal is truly timeless, but its flexibility and performance set new standards. The eight-strong model line-up includes still slimmer versions of the 225 centre speaker and Radius One centre, together with a Radius 200 centre-channel for shelf or rack mounting, and two enormously powerful yet super-compact active subwoofers: Radius 380 and 390.

The precision of the Radius design, available in a choice of the most popular gloss black, satin white and walnut finishes, is emphasised by its smoothly chamfered cabinet edges and the stylish silver profiles of the driver surrounds. Each satellite will look perfectly at home fitted snugly to the wall on an integrated fixing point designed for any standard wall bracket, or Monitor Audio’s own MASM speaker mount, optional for Radius 45 and 90. The Radius 225 and Radius One are complete with their own wall-mounting plates. Naturally the floor-standing Radius 270 tower, the Radius 200 and the ground-breaking Radius subs demonstrate the peerless installation versatility of the Radius approach, mixing acoustically-matched floor and wall designs for maximum audio and visual effect.

Once your choice of Radius speakers is in place, you’ll want to complement their clear, dynamic wideband response with the seismic presence of our wholly upgraded Radius sub cubes.

These ultra-compact bass engines represent a major leap forward in design and performance over their predecessors, generating jaw-dropping deep bass impact from side-firing systems of active and passive drivers – colour-coded to match cabinet finish – and massively up-rated amplifiers. The 380 has twin 8” drivers powered by a 200 W Class D amplifier – twice the power of the Radius 360 it replaces; the 390 uses twin 10” drivers powered by a 220 W Class D amp. Both amplifiers are DSP controlled and the passive ABR drivers are tuned low to produce deep, taut, size-defying bass. Impact, music and movie EQ presets and a 12 V trigger on each cube will help you to customise their miraculous low frequency output to your system and room. It’s all part of the Radius magic.

Technical Features:

  • Pure C-CAM Drivers

Radius subs and satellites owe their extraordinary sound quality to break-through engineering by Monitor Audio’s design team. In all but the diminutive Radius 45, the range utilises C-CAM drivers throughout.

C-CAM is Monitor Audio’s signature driver material, which has been refined over many years and features in all of our award-winning speakers. Ceramic-Coated Aluminium/Magnesium is an innovative material originally developed by the aerospace industry for use as blades in jet engines. It has ideal qualities as a driver cone, being extremely light but also very strong – it doesn’t bend like more conventional materials. This means you hear clearer, wider, more dynamic sound, even at high volumes

  • Tweeters

The Radius 1” (25 mm) C-CAM tweeter has been optimised to deliver the finest and widest performance within the compact Radius cabinets. It benefits from a more efficient rear-venting design, releasing air trapped and compressed at the back of the tweeter dome, and guiding it around the drive assembly to a rear-loading chamber. A more fluid movement of the dome lowers resonance and distortion across a wider operating range for greater accuracy, and a smoother, more natural crossover with the bass driver

  • Bass Drivers

Monitor Audios bass drivers feature concave cone profiles, introduced by our top-of-the-range Platinum speakers. The key design breakthrough for Radius is the integration of new cone geometry and drive mechanisms, involving a continuous radiating dish innovatively coupled to a more efficient drive assembly. Unlike traditional driver cones, the voice-coil of the Radius drivers sits beneath the cone rather than protrude through it, permitting a completely unbroken driver surface for greatly improved strength and fidelity. Extensive research and FEA modelling have allowed us to perfect the relationship between the radiating diaphragm and its motor design, introducing larger motor sizes and voice coils for increased excursion, higher power capability and reduced distortion

  • HiVe II Port Design

Straight from Platinum’s design blueprint, the HiVe II reflex port makes its Radius debut. It’s shaped to have the same effect on airflow as a gun-barrel on a bullet. Rifled grooves inside the port help to accelerate the flow and reduce turbulence, so air moves in and out of the port more efficiently, for a faster more dynamic bass response.

  • Design For Sound

For the first time the very original Radius series gave music and home cinema fans a living dimension to hi-fi sound. Now Radius expands that dimension still further, with more ways to experience genuine fidelity perfectly in-tune with your home.



  • Frequency Response - 120 Hz — 20 kHz
  • Sensitivity (1W@1M) - 87 dB
  • Nominal Impedance - 8 ohms
  • Power Handling (RMS) - 25 W
  • System Power Handling (RMS) - 50 W
  • Recommended Amplifier Requirements - 15 — 50 W
  • Maximum SPL - 101 dBa
  • Bass Alignment - Sealed Cabinet
  • Drive Unit Complement - 1 x 3" (75 mm) MMP II cone bass/mid-range Driver, 1 x 3/4" (20 mm) C-CAM Gold Dome tweeter
  • Cabinet Dimensions (H x W x D) - 100 x 100 x 100 mm (315/16 x 315/16 x 315/16")
  • Cabinet Dimensions (Including Grille and Terminals (H x W x D)) - 100 x 100 x 124 mm (315/16 x 315/16 x 47/8")
  • Cabinet Dimensions (Including Grille and Bracket (H x W x D)) - 100 x 100 x 162 mm (315/16 x 315/16 x 63/8")
  • Pre-Construction Bracket - Optional - Monitor Audio Speaker Mount (MASM)
  • Weight - 1 kg (2 lb 4 oz)

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