Monitor Audio Radius 3 4G Bookshelf Speakers

A Mini-Monitor With Full-Size Ambitions

Small speakers usually ask you to give something up. The Monitor Audio Radius 3 4G asks for less than most. It is a two-way standmount measuring 255 x 150 x 201 mm, about 10 by 5.9 by 7.9 inches, weighing 3.7 kg each.

The Radius line has run since 2004, and this fourth generation arrived in June 2026. The Radius 3 is the larger of the two standmounts, above the cube-shaped Radius 1 4G. Inside is a 4.5-inch C-CAM RST III bass-mid driver and a 25 mm C-CAM Gold Dome tweeter, crossing at 2.7 kHz. In-room response runs from 44 Hz to 35 kHz, and maximum peak SPL is 107 dB. Finishes are high gloss black and satin white, sold as a pair.

RST III Cones, a Vented Gold Dome, and a Bigger Port

C-CAM is Ceramic-Coated Aluminium/Magnesium, Monitor Audio’s cone material for decades. The fourth generation adds RST III cone geometry, a ribbed surface that pushes breakup further out of the audible band, plus a new magnet, an improved voice coil and better venting.

The tweeter was rebuilt around an external magnet motor rather than the usual internal puck magnet, and the dome is fully vented. A UD waveguide keeps dispersion even, which is why these hold a soundstage off-axis. Cabinet walls are thick for the size, and through-bolt bracing ties both drivers to the rear panel.

Bass comes from a rear HiVe II port tuned to 53 Hz, which Monitor Audio says is 50 percent larger than the previous generation’s.

What Reviewers Are Saying

David Price reviewed the Radius 3 4G for StereoNET on 15 June 2026, scoring it 8.5 out of 10 with an Applause Award. His verdict: "Clearly the best of Monitor Audio’s long line of small speakers so far." He praised the stereo imaging and the way the speaker holds together at volume.

He was candid about the limits. The deepest bass is essentially absent, and he does not rate it as the last word in neutrality at this price, noting that Monitor Audio’s larger Bronze models dig deeper. He also tried the supplied foam port plug: fitted, bass is tauter but there is less of it.

Who Is This Bookshelf Speaker Best For?

• Small rooms and apartments — A cabinet this size disappears where a floorstander dominates.
• Desktop and near-field listeners — Even dispersion and a tight cabinet suit close listening.
• Surround and height channels — Wall, stand or shelf mounting makes them easy to place.
• Anyone building around an existing amp — Monitor Audio asks 40 to 75 W into 8 ohms, which most integrateds cover.
• Not right if you want deep bass without a subwoofer — Response stops at 44 Hz. With floor space to spare and no sub, see our floorstanding speakers.

How Does It Connect to Your System?

These are passive speakers, so any stereo amplifier or AV receiver will drive them. Nominal impedance is 8 ohms, with a minimum of 4 ohms at 250 Hz. Give them real power and they open up.

Placement matters because the port fires backward. Close to a wall you get more bass and less control; pull them out and the low end tightens. Aim for tweeters at seated ear height, toe in slightly, then move an inch at a time until the center image locks.

Pairs Well With

Here is what usually goes around them.

• Integrated amplifiers — At 84 dB sensitivity, a capable amp matters more than usual. See our integrated amplifiers.
• Subwoofers — The partner if you want the bottom octave back. Browse our subwoofers.
• Speaker stands — Height is the cheapest improvement you can make. See our speaker stands.
• Speaker cables — Measure the run, then buy once. Shop speaker cables.

Frequently Asked Questions

Are the Radius 3 4G sold as a pair?

Yes. Each speaker weighs 3.7 kg, about 8 pounds.

How much amplifier power do they need?

Monitor Audio recommends 40 to 75 W into 8 ohms. Continuous handling is 75 W and sensitivity is 84 dB, so err toward more power.

Can they be wall mounted?

Yes, with Monitor Audio’s FIX-M bracket, sold separately. The Radius Floor Stand 4G and Desk Pad 4G also fit.

Do I need a subwoofer?

For music in a small room, often not. For films, add one. Monitor Audio recommends a subwoofer for full-range performance.

How close to a wall can they go?

The port fires backward, so leave breathing room. Closer means more bass but less control.

See It in Action

Monitor Audio’s channel introduces the whole Radius Series 4G, Radius 3 included.

Monitor Audio also unboxes the Radius Series 4G, carton by carton.

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Learn More

Want to learn more about speaker placement, amplifier matching, or adding a subwoofer? Visit our Learning Center for guides, tips, and expert advice.