Review: KEF iQ50 Compact Floorstanding Speakers

Accuracy and affordability for audiophiles

KEF iQ50 Floorstanding Speakers

Audiophiles and avid music lovers know the KEF name well and associate it with fine loudspeakers. KEF is a British speaker manufacturer founded in 1961 by the late Raymond Cooke, a former electrical engineer with the BBC who loved music and endeavored to design a better speaker for music reproduction. Almost fifty years later, KEF speakers are still found in fine audio systems and with the introduction of the Q Series speakers, music lovers with exacting tastes but more modest budgets can enjoy KEF speakers.

KEF Design

The iQ50 is a 2 ½-way floorstanding bass reflex speaker in the middle of the Q series line with a sound that belies its small size. It could be classed as a mini tower. The iQ50 enclosures are curved, a characteristic KEF design that minimizes internal standing waves and the cabinets are braced inside to produce a solid, acoustically inert enclosure. The iQ50 has one 5.25" bass driver, a 5.25" mid-bass driver and a concentrically aligned .75" aluminum dome tweeter, part of the KEF Uni-Q story. The iQ50s can also be bi-wired or bi-amplified.

The Uni-Q driver configuration is a signature KEF technology. The Uni-Q design precisely aligns the sound waves from the midrange and tweeter to create a unified sound field. The acoustic centers or voice coils of the drivers are time aligned in order to achieve a 'point source' speaker where all sounds emanate from the same point in space. Interference between the sound waves from different drivers is minimized and the results provide a coherent sound quality with wide dispersion characteristics. A coherent speaker presents a sound wave as if listening to a single driver for all frequencies, not separate drivers interconnected by a crossover. In our experience, sound coherency is one of the most important and often overlooked characteristics of accurate music reproduction.

The Uni-Q array in the Q Series speakers has been further refined with a 'tangerine' waveguide surrounding the tweeter that helps direct and control the sound coming from the tweeter.

First Impressions: Movies

It takes time to become familiar with a speaker's character and sound qualities, but first impressions are always important. It's helpful to listen casually before doing any critical listening, but the initial impression of the iQ50s was that it's incredibly smooth and has well-defined bass with both music and movie sources.

Good bass can be difficult to achieve even when speakers are correctly placed in a room with good acoustic qualities, but the iQ50s had great bass right out of the box with excellent extension. There were no apparent peaks or dips in low-frequency response and bass sounded evenly distributed throughout the room.

A case in point was the sixth season of the Fox series '24' (DVD, Dolby Digital), which had abundant suspense-inducing deep bass. Considering their size, the KEFs reached unbelievable bass depths without a subwoofer. It was a surprising visual disconnect. In fact, we checked the sub to make sure it was not operating. Normally, we would use a subwoofer for soundtracks with an LFE channel, but this was a good test of the KEF iQ50s and they clearly passed.

Lasting Impressions: Music

Mary Black's 'Columbus' from her No Frontiers CD (Gift Horse Records), has a robust bass track that the KEF iQ50s reproduced with solid definition and tightness. Diana Krall's 'How Insensitive' ('From This Moment On', CD, Verve Records) combined well-defined bass with spot-on center imaging.

The iQ50s have a front mounted port or vent that comes with a removable foam plug in the event bass is too strong for personal listening preferences, but we did not find it necessary to use the plugs.

Moving beyond bass, the KEF iQ50s had a proportional, balanced quality that bespeaks a neutral sounding loudspeaker. Mids and vocals had a natural timbre and the upper ranges were detailed and accurate but averted any high-end sizzle or tizzyness that tends to wear on the ears and quickly results in listening fatigue. The KEFs delivered a delicate, relaxed listening experience, the kind that lets you enjoy music without the boom-sizzle. It's an excellent example of sound coherency and it makes casual and critical listening effortless and enjoyable.


The KEF iQ50 speakers are among the best speakers in the sub-$1000 per pair price range and it's clear to us why serious music lovers revere KEF speakers. Fifty years of speaker design research and refinement has paid off. Although the KEF speakers sounded great with movie sources, their real strong points are music reproduction. Neutral, uncolored and balanced are a few of the descriptions we'd use.

Their compact size is unobtrusive and the fine fit and finish of the cabinets are impressive. With three finishes available, Black Ash, Dark Apple, and American Walnut the iQ50s will blend easily with almost any room décor.

KEF recommends 15 – 130 watts for the iQ50s, but with a sensitivity specification of only 88 dB (relatively low), we would suggest an amp or receiver with 100 watts per channel or more to get the most dynamic range from the KEF iQ50s.


  • 1- 5.25" bass driver
  • 1- 5.25" Uni-Q mid-bass driver and one 0.75" aluminum dome tweeter in Uni-Q array
  • Frequency response: 40 Hz – 40 kHz
  • Crossover frequency: 2.5 kHz
  • Recommended power: 15 – 130 watts
  • Sensitivity: 88 dB
  • Maximum output: 109 dB
  • Nominal impedance: 8 ohms
  • Magnetically shielded: yes
  • Dimensions (W x H x D): 6.9" x 32" x 10.3"
  • Weight: 22.5 lbs.