KEF Q350 vs Dynaudio Special Forty

Last updated: August 24, 2026

Short answer: the Dynaudio Special Forty for better sound quality, the KEF Q350 for the lower price. The Dynaudio Special Forty ranks #84 of 125 bookshelf speakers at $3600. The KEF Q350 ranks #101 at $699, $2901 cheaper.

What the KEF Q350 offers: CEA2034 spinorama shows a reasonably flat on-axis response with excellent directivity, aided by the coaxial Uni-Q driver. Vertical directivity is better than most non-coaxial two-way speakers, another benefit of the concentric design. Watch for: Two resonances at 700Hz and 1.2kHz show up on-axis, alongside an upper-bass boost. Predicted in-room response looks a bit boomy as a result. Distortion climbs substantially in the 100Hz-1kHz range at 96dB SPL/1m, with a distinct resonance-driven peak around 900Hz-1kHz at both test levels.

What the Dynaudio Special Forty offers: Smooth, “buttery” overall tonal character consistent with Dynaudio’s house sound. Surprisingly precise, focused imaging despite wide horizontal radiation (about ±70°) - atypical, since wide-radiating speakers usually sacrifice some image precision in reflective rooms. Strong output capability: reached 100-101dB average at 3.5 meters with no audible distortion or woofer distress, and compression testing at 102dB shows the cabinet holding up mechanically well at extreme output. Bass reaches a genuine 50Hz (potentially 40Hz) in most rooms from a rear-ported design. Distortion stays below 1% at 86dB and doesn’t cross 3% THD until about 50Hz even at 96dB. Extra weight and impact on snares and percussion around 700-800Hz that the reviewer found appealing on many tracks. Watch for: A glaring, sometimes sibilant quality around 3-4kHz was the most noticeable issue in listening, the one thing the reviewer would want notched out with EQ. Multiple enclosure resonances appear between 500Hz-1kHz across on-axis, listening window, early-reflections, and sound-power measurements, corroborated by independent third-party CSD data showing similar 500-800Hz cabinet resonances. A dip around 1.2kHz traces to a cone-edge-to-surround compliance mismatch in the driver itself (confirmed by testing the bare driver’s impedance) - a known artifact common to many similarly-sized drivers across several manufacturers, contributing to elevated second-order distortion in that region. A somewhat laid-back, recessed 1-2kHz character (sometimes described as a “BBC dip”) gives an overall subdued quality that isn’t overtly problematic but shapes the tonal balance. Impedance drops below 3 ohms in the 100-200Hz region, requiring a genuinely 4-ohm-stable amplifier rather than an AVR. Rear port means it can’t be placed directly against a wall.

Buy the KEF Q350 if the price matters more than sound quality. Buy the Dynaudio Special Forty if sound quality matters more than the price.

If sound quality matters at all to you, skip the KEF Q350. It ranks near the bottom of the 125 bookshelf speakers, so look higher up the list instead.

KEF Q350 vs Dynaudio Special Forty

Specifications Side By Side

KEF Q350 Dynaudio Special Forty
Price$699.00 Discontinued$3600
Ranked#101 of 125 in Large Size Bookshelf Speakers#84 of 125 in Large Size Bookshelf Speakers
Bass Extension (-10dB)38Hz (measured, Audio Science Review)39Hz (measured, Erin’s Audio Corner)
Bass Extension (-3dB)70Hz (measured, Audio Science Review)54Hz (measured, Erin’s Audio Corner)
Impedance4 ohms6 ohms nominal (4.9 ohms minimum above 80Hz, measured, Erin’s Audio Corner)
Sensitivity86dB (measured, Audio Science Review)83.5dB (measured, Erin’s Audio Corner; 86dB manufacturer specified)
Drivers25mm tweeter + 165mm woofer5.9" MSP (Magnesium Silicate Polymer) cone woofer, 1" Esotar soft dome tweeter
DiscontinuedYes-
Weight29.5 lbs / 13.4 kg17.9 lbs / 8.1 kg each
Dimensions14.1"H x 8.3"W x 12"D (358.0 x 210.0 x 306.0 mm)14.1"H x 7.7"W x 12.1"D (358.1 x 195.6 x 307.3 mm)
Woofer Cabinetported, rearported

More useful head-to-heads from the same speaker class:

Prices on this page were last checked August 24, 2026 at 6:53 AM 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

KEF Q350: $699.00 Discontinued Amazon eBay

KEF Q350 ranking card

Pros: CEA2034 spinorama shows a reasonably flat on-axis response with excellent directivity, aided by the coaxial Uni-Q driver. Vertical directivity is better than most non-coaxial two-way speakers, another benefit of the concentric design.

Cons: Two resonances at 700Hz and 1.2kHz show up on-axis, alongside an upper-bass boost. Predicted in-room response looks a bit boomy as a result. Distortion climbs substantially in the 100Hz-1kHz range at 96dB SPL/1m, with a distinct resonance-driven peak around 900Hz-1kHz at both test levels. Discontinued.

Bass Extension (-10dB)38Hz (measured, Audio Science Review)
Bass Extension (-3dB)70Hz (measured, Audio Science Review)
Dimensions14.1"H x 8.3"W x 12"D (358.0 x 210.0 x 306.0 mm)
DiscontinuedYes
Drivers25mm tweeter + 165mm woofer
Impedance4 ohms
Sensitivity86dB (measured, Audio Science Review)
Weight29.5 lbs / 13.4 kg
Woofer Cabinetported, rear

Dynaudio Special Forty: $3600 Safeandsoundhq eBay

Dynaudio Special Forty ranking card

Pros: Smooth, “buttery” overall tonal character consistent with Dynaudio’s house sound. Surprisingly precise, focused imaging despite wide horizontal radiation (about ±70°) - atypical, since wide-radiating speakers usually sacrifice some image precision in reflective rooms. Strong output capability: reached 100-101dB average at 3.5 meters with no audible distortion or woofer distress, and compression testing at 102dB shows the cabinet holding up mechanically well at extreme output. Bass reaches a genuine 50Hz (potentially 40Hz) in most rooms from a rear-ported design. Distortion stays below 1% at 86dB and doesn’t cross 3% THD until about 50Hz even at 96dB. Extra weight and impact on snares and percussion around 700-800Hz that the reviewer found appealing on many tracks.

Cons: A glaring, sometimes sibilant quality around 3-4kHz was the most noticeable issue in listening, the one thing the reviewer would want notched out with EQ. Multiple enclosure resonances appear between 500Hz-1kHz across on-axis, listening window, early-reflections, and sound-power measurements, corroborated by independent third-party CSD data showing similar 500-800Hz cabinet resonances. A dip around 1.2kHz traces to a cone-edge-to-surround compliance mismatch in the driver itself (confirmed by testing the bare driver’s impedance) - a known artifact common to many similarly-sized drivers across several manufacturers, contributing to elevated second-order distortion in that region. A somewhat laid-back, recessed 1-2kHz character (sometimes described as a “BBC dip”) gives an overall subdued quality that isn’t overtly problematic but shapes the tonal balance. Impedance drops below 3 ohms in the 100-200Hz region, requiring a genuinely 4-ohm-stable amplifier rather than an AVR. Rear port means it can’t be placed directly against a wall.

Bass Extension (-10dB)39Hz (measured, Erin's Audio Corner)
Bass Extension (-3dB)54Hz (measured, Erin's Audio Corner)
Dimensions14.1"H x 7.7"W x 12.1"D (358.1 x 195.6 x 307.3 mm)
Drivers5.9" MSP (Magnesium Silicate Polymer) cone woofer, 1" Esotar soft dome tweeter
Impedance6 ohms nominal (4.9 ohms minimum above 80Hz, measured, Erin's Audio Corner)
Sensitivity83.5dB (measured, Erin's Audio Corner; 86dB manufacturer specified)
Weight17.9 lbs / 8.1 kg each
Woofer Cabinetported