Short answer: the Bowers & Wilkins Formation Flex. It ranks #11 of 24 powered bookshelf speakers by sound quality (rated 3.5/5); the Kanto YU4 ranks #14 (rated 3.3/5).
Why pick the Bowers & Wilkins Formation Flex: ASR’s Klippel data gives a 6.43 predicted preference score with an ideal subwoofer and broad horizontal coverage. The tradeoff: Standalone preference is only 3.69.
Why pick the Kanto YU4: Phono, optical and Bluetooth inputs, remote control and a subwoofer output make it convenient for a compact multi-source system. Watch for: Standalone preference is only 2.89, with a -3dB point around 86Hz and a 4.2dB midrange response span.
Buy the Bowers & Wilkins Formation Flex. It is rated higher for sound quality than the Kanto YU4.
Want more options? Browse the full Powered Home rankings.
Specifications Side By Side
| Bowers & Wilkins Formation Flex | Kanto YU4 | |
|---|---|---|
| Price | £898 per pair | $479.99 per pair |
| Ranked | #11 of 24 in Small Size Powered Bookshelf Speakers | #14 of 24 in Small Size Powered Bookshelf Speakers |
| Enclosure | 2-way active wireless | Powered 2-way, rear-ported |
| Drivers | 1" decoupled double-dome tweeter, 4" woven-glass woofer | 1" silk-dome tweeter, 4" Kevlar woofer |
| Dimensions | 8.5H x 5.1W x 5.1D in | 8.7H x 5.5W x 7.5D in |
| Weight | 5.1 lbs (2.3 kg) each | 6.8 lbs (3.1 kg) powered / 5.5 lbs (2.5 kg) passive |
| Amplifier Power | 100W each (2 x 50W) | 70W RMS / 140W peak per pair |
| Wireless | AirPlay 2, Spotify Connect, Bluetooth, Formation mesh | - |
| Country | United Kingdom (design) | - |
| Spinorama Preference Score | 3.69 | 2.89 |
| Spinorama Preference Score with Perfect Sub | 6.43 | 5.83 |
| Inputs | AirPlay 2, Spotify Connect, Roon Ready, Bluetooth, Wi-Fi | Bluetooth, optical, RCA/phono, 3.5mm |
| XLR Input | No | No |
| RCA Input | No | Yes |
| TRS Input | No | No |
| Optical Input | No | Yes |
| Coaxial Input | No | No |
| USB Input | No | No |
| HDMI Input | No | No |
| AES Input | No | No |
| Aux Input | No | Yes |
| Bluetooth | Yes, 4.1 | Yes, 4.0 |
| Frequency Response | 50Hz - 28kHz (Manufacturer specified) | 60Hz-20kHz |
| Bluetooth Codecs | - | SBC, aptX |
| Outputs | - | Subwoofer |
| Subwoofer Output | - | Yes |
Related Speaker Comparisons
More worthwhile head-to-heads for Bowers & Wilkins Formation Flex:
- Cambridge Audio L/R S vs Bowers & Wilkins Formation Flex
- HiVi Swan X3 vs Bowers & Wilkins Formation Flex
- Sovox MiniMax3 vs Bowers & Wilkins Formation Flex
- Bowers & Wilkins Formation Flex vs Fostex PM0.3
- Bowers & Wilkins Formation Flex vs Audioengine A2+
Prices on this page were last checked September 23, 2026 at 11:24 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
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The Two Speakers In Full
Bowers & Wilkins Formation Flex: £898 per pair Bowers & Wilkins eBay
Pros: ASR’s Klippel data gives a 6.43 predicted preference score with an ideal subwoofer and broad horizontal coverage. Its wireless stereo-pair capability and network streaming can suit a minimalist system without conventional source cables. The measured tonal result is more credible than judging sound quality from the compact wireless format alone.
Cons: Standalone preference is only 3.69. The response rises toward the treble, and the -3dB point is about 95Hz, so lower bass is substantially reduced even though the preference model’s separate LFX metric is 62Hz. Those two bass metrics are not interchangeable. A stereo pair is costly, and the lack of conventional analog input limits system flexibility.
Full Bowers & Wilkins Formation Flex review and specifications →
| AES Input | No |
|---|---|
| Amplifier Power | 100W each (2 x 50W) |
| Aux Input | No |
| Bluetooth | Yes, 4.1 |
| Coaxial Input | No |
| Country | United Kingdom (design) |
| Dimensions | 8.5H x 5.1W x 5.1D in |
| Drivers | 1" decoupled double-dome tweeter, 4" woven-glass woofer |
| Enclosure | 2-way active wireless |
| Frequency Response | 50Hz - 28kHz (Manufacturer specified) |
| HDMI Input | No |
| Inputs | AirPlay 2, Spotify Connect, Roon Ready, Bluetooth, Wi-Fi |
| Optical Input | No |
| RCA Input | No |
| Spinorama Preference Score | 3.69 |
| Spinorama Preference Score with Perfect Sub | 6.43 |
| TRS Input | No |
| USB Input | No |
| Weight | 5.1 lbs (2.3 kg) each |
| Wireless | AirPlay 2, Spotify Connect, Bluetooth, Formation mesh |
| XLR Input | No |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Bowers & Wilkins Formation Flex vs Fostex PM0.3
- Bowers & Wilkins Formation Flex vs Audioengine A2+
- Bowers & Wilkins Formation Flex vs Sovox MiniMax3
- Bowers & Wilkins Formation Flex vs Monacor SOUND-4BT
- Bowers & Wilkins Formation Flex vs HiVi Swan X3
- Bowers & Wilkins Formation Flex vs Klipsch ProMedia Lumina
- Bowers & Wilkins Formation Flex vs Monoprice Monolith MM-3
- Bowers & Wilkins Formation Flex vs Audioengine HD3
- See all 9 comparisons
Kanto YU4: $479.99 per pair Kanto eBay
Pros: Phono, optical and Bluetooth inputs, remote control and a subwoofer output make it convenient for a compact multi-source system. ASR’s measured horizontal coverage is broad enough for some freedom of seating position. The ideal-subwoofer preference score of 5.83 indicates that bass support would materially improve its usefulness.
Cons: Standalone preference is only 2.89, with a -3dB point around 86Hz and a 4.2dB midrange response span. Response irregularities remain even after bass extension is removed from the comparison, so a subwoofer alone will not make it neutral. Sensitivity measured at an arbitrary powered-speaker gain setting is not a reliable basis for judging efficiency or maximum volume.
Full Kanto YU4 review and specifications →
| AES Input | No |
|---|---|
| Amplifier Power | 70W RMS / 140W peak per pair |
| Aux Input | Yes |
| Bluetooth | Yes, 4.0 |
| Bluetooth Codecs | SBC, aptX |
| Coaxial Input | No |
| Dimensions | 8.7H x 5.5W x 7.5D in |
| Drivers | 1" silk-dome tweeter, 4" Kevlar woofer |
| Enclosure | Powered 2-way, rear-ported |
| Frequency Response | 60Hz-20kHz |
| HDMI Input | No |
| Inputs | Bluetooth, optical, RCA/phono, 3.5mm |
| Optical Input | Yes |
| Outputs | Subwoofer |
| RCA Input | Yes |
| Spinorama Preference Score | 2.89 |
| Spinorama Preference Score with Perfect Sub | 5.83 |
| Subwoofer Output | Yes |
| TRS Input | No |
| USB Input | No |
| Weight | 6.8 lbs (3.1 kg) powered / 5.5 lbs (2.5 kg) passive |
| XLR Input | No |
- Links
- Reviews, Comparisons and Sound Samples
- Kanto YU4 Measurements (spinorama.org)
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