Short answer: the KEF R3. It ranks #15 of 130 bookshelf speakers by sound quality at $2200; the Sonus Faber Sonetto II G2 ranks #103 and costs $3500, so there is little reason to consider the other one.
What the KEF R3 offers: True three-way stand-mount with a 6.5-inch woofer below KEF’s 5-inch Uni-Q midrange/1-inch tweeter. Erin measured approximately 86-87dB/2.83V/1m sensitivity, exceptionally low sub-1% distortion at 86dB and orderly directivity in both planes. The coaxial geometry maintains image stability across seats, while Flexible Port Technology avoids the strong midrange port resonance common to rear-vented competitors. A 110W Parasound drove it successfully in Erin’s listening. Watch for: The low-frequency alignment rolls gradually rather than delivering high-output sub-bass; KEF specifies 58Hz +/-3dB and Erin’s high-level data supports using an 80Hz subwoofer crossover. Narrow high-frequency features and natural Uni-Q narrowing toward the top octave make toe angle audible, although off-axis tracking remains smooth. Sensitivity is moderate, the cabinet weighs almost 30 lb, and this original R3 lacks the Meta successor’s MAT absorber.
What the Sonus Faber Sonetto II G2 offers: Two-way design with a 1.125” damped Apex Dome silk tweeter and 6.5” cone woofer, using a base of concrete, aluminum, and steel with under-cabinet venting. Notably more neutral than Sonus Faber’s own Lumina 2, which runs 2-5dB hotter in the treble. Horizontal directivity narrows at a fairly constant, well-behaved rate rather than narrowing-then-widening-then-narrowing like some rivals (including the Lumina 2), meaning sidewall reflections match the direct sound well enough that the reviewer doesn’t recommend sidewall absorption for this speaker. The tweeter-to-woofer crossover handoff around 3kHz looks clean, suggesting a higher-order crossover than typical for the size/price class. Good dynamic range - the low end loses only about 2dB from 76dB to 96dB, otherwise holding up well. Not a difficult amplifier load (about 4.2 ohms minimum impedance). Bass extension reaches a genuine 50Hz in-room, fuller than the Lumina 2. Watch for: Sounds notably bright pointed directly on-axis; toeing the speaker out about 30° reduces treble energy and sibilance meaningfully. A resonance around 700Hz gives vocals a slightly nasal, hollow quality. A dip in the upper midrange (roughly 1-2kHz) reduces perceived detail and attack, while the elevated treble can read as “analytical” or “detailed” to some listeners despite being a coloration rather than true resolution. Needs more clearance from the rear wall than some rivals - about 1.5-2 feet in an ideal room, more or less depending on your specific room modes - or the 80-120Hz region can become boomy. Vertical listening window is limited to about ±10-15° from the tweeter axis. Some unexplained directivity irregularities appear around 1.2kHz and 1.6kHz, possibly port-related, along with a longer decay in the 800Hz-1600Hz range in burst-decay measurements. Multitone distortion approaches the reviewer’s 3% threshold through the midrange, though likely not obviously audible without direct A/B comparison. A resonance in the cabinet appears around 400Hz in impedance measurements.
Buy the KEF R3. It ranks higher for sound quality than the Sonus Faber Sonetto II G2 and costs less, so there is no real case for the other one.
The Sonus Faber Sonetto II G2 is not a sound-quality pick. It sits near the bottom of the 130 bookshelf speakers; there are better options higher up.
Looking for alternatives? See the complete Passive Home rankings.
Specifications Side By Side
| KEF R3 | Sonus Faber Sonetto II G2 | |
|---|---|---|
| Price | $2,200 per pair | $3500 per pair |
| Ranked | #15 of 130 in Large Size Bookshelf Speakers | #103 of 130 in Large Size Bookshelf Speakers |
| Bass Extension (-3dB) | Approximately 58Hz (manufacturer specified; consistent with Erin's measured roll-off) | 62Hz (measured, Erin's Audio Corner) |
| Bass Extension (-10dB) | 35.2Hz (measured, Audio Science Review) | 38Hz (measured, Erin's Audio Corner) |
| Sensitivity | Approximately 86-87dB/2.83V/1m (measured, Erin's Audio Corner) | 87dB (measured, Erin's Audio Corner) |
| Impedance | 8 ohms nominal; suitable for Erin's 4/8-ohm-rated amplifier | 4 ohms nominal (4.2 ohms minimum, measured by Erin's Audio Corner) |
| Drivers | 1" tweeter coaxial with 5" midrange; 6.5" woofer | 1x 6.5" mid-woofer (paper cone), 1x 1.1" (28mm) DAD soft dome tweeter |
| Dimensions | 16.6"H x 7.9"W x 13.2"D | 16.3"H x 8.9"W x 14"D (414.3 x 227.0 x 355.6 mm) |
| Woofer Cabinet | ported, rear Flexible Port | ported, front |
| Weight | - | 38.4 lbs (17.4 kg) |
| Spinorama Preference Score | - | 3.34 |
| Spinorama Preference Score with Perfect Sub | - | 5.62 |
Related Speaker Comparisons
How KEF R3 compares with other leading options:
- KEF R3 vs Perlisten S4b
- KEF Reference 1 Meta vs KEF R3
- KEF R3 vs GR-Research NX-Studio
- AsciLab C6B vs KEF R3
- KEF R3 vs Audio First Cadentia 3
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The Two Speakers In Full
KEF R3: $2,200 per pair Amazon eBay
Pros: True three-way stand-mount with a 6.5-inch woofer below KEF’s 5-inch Uni-Q midrange/1-inch tweeter. Erin measured approximately 86-87dB/2.83V/1m sensitivity, exceptionally low sub-1% distortion at 86dB and orderly directivity in both planes. The coaxial geometry maintains image stability across seats, while Flexible Port Technology avoids the strong midrange port resonance common to rear-vented competitors. A 110W Parasound drove it successfully in Erin’s listening. Measured bass extension of 35.2Hz (-10dB), with a measured sensitivity of 87dB.
Cons: The low-frequency alignment rolls gradually rather than delivering high-output sub-bass; KEF specifies 58Hz +/-3dB and Erin’s high-level data supports using an 80Hz subwoofer crossover. Narrow high-frequency features and natural Uni-Q narrowing toward the top octave make toe angle audible, although off-axis tracking remains smooth. Sensitivity is moderate, the cabinet weighs almost 30 lb, and this original R3 lacks the Meta successor’s MAT absorber.
Full KEF R3 review and specifications →
| Bass Extension (-10dB) | 35.2Hz (measured, Audio Science Review) |
|---|---|
| Bass Extension (-3dB) | Approximately 58Hz (manufacturer specified; consistent with Erin's measured roll-off) |
| Dimensions | 16.6"H x 7.9"W x 13.2"D |
| Drivers | 1" tweeter coaxial with 5" midrange; 6.5" woofer |
| Impedance | 8 ohms nominal; suitable for Erin's 4/8-ohm-rated amplifier |
| Sensitivity | Approximately 86-87dB/2.83V/1m (measured, Erin's Audio Corner) |
| Woofer Cabinet | ported, rear Flexible Port |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
Sonus Faber Sonetto II G2: $3500 per pair Crutchfield eBay
Pros: Two-way design with a 1.125” damped Apex Dome silk tweeter and 6.5” cone woofer, using a base of concrete, aluminum, and steel with under-cabinet venting. Notably more neutral than Sonus Faber’s own Lumina 2, which runs 2-5dB hotter in the treble. Horizontal directivity narrows at a fairly constant, well-behaved rate rather than narrowing-then-widening-then-narrowing like some rivals (including the Lumina 2), meaning sidewall reflections match the direct sound well enough that the reviewer doesn’t recommend sidewall absorption for this speaker. The tweeter-to-woofer crossover handoff around 3kHz looks clean, suggesting a higher-order crossover than typical for the size/price class. Good dynamic range - the low end loses only about 2dB from 76dB to 96dB, otherwise holding up well. Not a difficult amplifier load (about 4.2 ohms minimum impedance). Bass extension reaches a genuine 50Hz in-room, fuller than the Lumina 2. Measured bass extension of 62Hz (-3dB), with a measured sensitivity of 87dB.
Cons: Sounds notably bright pointed directly on-axis; toeing the speaker out about 30° reduces treble energy and sibilance meaningfully. A resonance around 700Hz gives vocals a slightly nasal, hollow quality. A dip in the upper midrange (roughly 1-2kHz) reduces perceived detail and attack, while the elevated treble can read as “analytical” or “detailed” to some listeners despite being a coloration rather than true resolution. Needs more clearance from the rear wall than some rivals - about 1.5-2 feet in an ideal room, more or less depending on your specific room modes - or the 80-120Hz region can become boomy. Vertical listening window is limited to about ±10-15° from the tweeter axis. Some unexplained directivity irregularities appear around 1.2kHz and 1.6kHz, possibly port-related, along with a longer decay in the 800Hz-1600Hz range in burst-decay measurements. Multitone distortion approaches the reviewer’s 3% threshold through the midrange, though likely not obviously audible without direct A/B comparison. A resonance in the cabinet appears around 400Hz in impedance measurements.
Full Sonus Faber Sonetto II G2 review and specifications →
| Bass Extension (-10dB) | 38Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 62Hz (measured, Erin's Audio Corner) |
| Dimensions | 16.3"H x 8.9"W x 14"D (414.3 x 227.0 x 355.6 mm) |
| Drivers | 1x 6.5" mid-woofer (paper cone), 1x 1.1" (28mm) DAD soft dome tweeter |
| Impedance | 4 ohms nominal (4.2 ohms minimum, measured by Erin's Audio Corner) |
| Sensitivity | 87dB (measured, Erin's Audio Corner) |
| Spinorama Preference Score | 3.34 |
| Spinorama Preference Score with Perfect Sub | 5.62 |
| Weight | 38.4 lbs (17.4 kg) |
| Woofer Cabinet | ported, front |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Sonus Faber Sonetto II G2 vs Audio Craftsmen Victoria
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- Sonus Faber Sonetto II G2 vs Sonus Faber Lumina II Amator
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