Short answer: the KEF R11 Meta for better sound quality, the Infinity Primus 360 for the lower price. The KEF R11 Meta ranks #26 of 68 floorstanding speakers at $3499.99. The Infinity Primus 360 ranks #40 at $650, $2849.99 cheaper.
What the KEF R11 Meta offers: CEA2034 spinorama shows a generally flat on-axis response with good directivity and very deep bass extension (F10 of 30Hz). Predicted in-room response is very smooth aside from the small 1-1.5kHz dip. The coaxial Uni-Q driver gives excellent, symmetric vertical directivity, unusual for a tower speaker. Distortion is incredibly low even down to 30Hz at 86dB SPL/1m, and stays low even at 96dB and 102dB SPL/1m - the reviewer found essentially no audible tonality change across that whole output range. Watch for: A dip around 1-1.2kHz on-axis is attributed to a diffraction effect, and shows up as a smaller dip in the predicted in-room response. Horizontal beamwidth of about ±40 degrees is on the narrower side, though the transition from wide to constant directivity is smooth. Minimum impedance dips to 3.2 ohms around 580Hz, calling for an amplifier comfortable with a demanding load. 4-ohm nominal impedance overall.
What the Infinity Primus 360 offers: A three-way tower from 2005 (two 6.5” mid-woofers, a 4” mid-range, and a 0.75” dome tweeter, 8 ohms nominal) that holds up remarkably well by modern measurement standards: on-axis linearity is within about ±2dB, and the listening window stays consistent out to roughly ±30° horizontal and ±10° vertical off the mid-range axis. Horizontal directivity is well controlled out to about ±75° before tonality starts to drift, meaning the reflected sound in a room stays close in character to the direct sound - a speaker that takes EQ well without fighting itself. Harmonic distortion measures low at both 86dB and 96dB, and multitone distortion stays under the reviewer’s 3% threshold. Silky, smooth midrange with a rich lower-midrange/upper-bass character. No mechanical issues or surround degradation found in a 20-year-old pair, and a second unit measured within about 1-1.5dB of the first, suggesting good long-term consistency for the design. Watch for: Manufacturer-spec sensitivity of 93dB runs about 3-4dB optimistic versus the measured 89.4dB average. Bass output drops off fairly quickly below about 50Hz in-room (F3 53Hz, F10 37Hz), so a subwoofer is needed for real low-end extension. Resonances show up around 170Hz, 220Hz, and 350Hz. On-axis, the lower treble can sound a bit bright or sibilant when the speaker is aimed directly at the listener; toeing out about 10-15° (rather than the more extreme 30°) gave the best balance, and some sidewall acoustic absorption further tamed a 4-5kHz peak. Placed close to the rear wall, bass gets boomy - pulling the speakers out about a foot resolves most of it, with roughly 1.5 feet from the wall as a good compromise between bass character and typical room aesthetics. Straying beyond about 25° above or below the mid-range axis introduces audible suckout. No longer in production, so it’s a used/secondhand purchase only.
Buy the KEF R11 Meta if sound quality matters more than the price. Buy the Infinity Primus 360 if the price matters more than sound quality.
Specifications Side By Side
| KEF R11 Meta | Infinity Primus 360 | |
|---|---|---|
| Price | $3,499.99 | $650.00 Discontinued |
| Ranked | #26 of 68 in Large Size Floorstanding Speakers | #40 of 68 in Large Size Floorstanding Speakers |
| Bass Extension (-10dB) | 31Hz (measured, Audio Science Review) | 37Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-3dB) | 64Hz (measured, Audio Science Review) | 53Hz (measured, Erin’s Audio Corner) |
| Dimensions | 51"H x 12.2"W x 15.1"D (1295.4 x 309.9 x 383.5 mm) | 39"H x 8-1/8"W x 13-7/8"D (990 x 208 x 330mm) |
| Impedance | 4 ohms | 8 ohms nominal, 3.5 ohms minimum (measured, Erin’s Audio Corner) |
| Drivers | 4 x 165 mm (6.5 in.) hybrid aluminium cone woofers, 125 mm (5 in.) aluminium cone midrange, 25 mm (1 in.) vented aluminium dome with MAT tweeter | Two 6.5" mid-woofers, 4" mid-range, 0.75" dome tweeter |
| Sensitivity | 89.5dB | 89.4dB (measured, Erin’s Audio Corner; 93dB manufacturer specified) |
| Weight | 80.5 lbs / 36.5 kg each | 48.5 lbs (48.5 lbs / 22 kg) each |
| Woofer Cabinet | ported, rear | - |
| Discontinued | - | Yes |
| Frequency Response | - | 38Hz - 20kHz (±3dB, Manufacturer specified) |
| Crossovers | - | 350Hz & 3.3kHz, 24dB/octave |
| Recommended Power | - | 10-200W |
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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 R11 Meta: $3,499.99 Amazon eBay
Pros: CEA2034 spinorama shows a generally flat on-axis response with good directivity and very deep bass extension (F10 of 30Hz). Predicted in-room response is very smooth aside from the small 1-1.5kHz dip. The coaxial Uni-Q driver gives excellent, symmetric vertical directivity, unusual for a tower speaker. Distortion is incredibly low even down to 30Hz at 86dB SPL/1m, and stays low even at 96dB and 102dB SPL/1m - the reviewer found essentially no audible tonality change across that whole output range.
Cons: A dip around 1-1.2kHz on-axis is attributed to a diffraction effect, and shows up as a smaller dip in the predicted in-room response. Horizontal beamwidth of about ±40 degrees is on the narrower side, though the transition from wide to constant directivity is smooth. Minimum impedance dips to 3.2 ohms around 580Hz, calling for an amplifier comfortable with a demanding load. 4-ohm nominal impedance overall.
Full KEF R11 Meta review and specifications →
| Bass Extension (-10dB) | 31Hz (measured, Audio Science Review) |
|---|---|
| Bass Extension (-3dB) | 64Hz (measured, Audio Science Review) |
| Dimensions | 51"H x 12.2"W x 15.1"D (1295.4 x 309.9 x 383.5 mm) |
| Drivers | 4 x 165 mm (6.5 in.) hybrid aluminium cone woofers, 125 mm (5 in.) aluminium cone midrange, 25 mm (1 in.) vented aluminium dome with MAT tweeter |
| Impedance | 4 ohms |
| Sensitivity | 89.5dB |
| Weight | 80.5 lbs / 36.5 kg each |
| Woofer Cabinet | ported, rear |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
Infinity Primus 360: $650.00 Discontinued eBay
Pros: A three-way tower from 2005 (two 6.5” mid-woofers, a 4” mid-range, and a 0.75” dome tweeter, 8 ohms nominal) that holds up remarkably well by modern measurement standards: on-axis linearity is within about ±2dB, and the listening window stays consistent out to roughly ±30° horizontal and ±10° vertical off the mid-range axis. Horizontal directivity is well controlled out to about ±75° before tonality starts to drift, meaning the reflected sound in a room stays close in character to the direct sound - a speaker that takes EQ well without fighting itself. Harmonic distortion measures low at both 86dB and 96dB, and multitone distortion stays under the reviewer’s 3% threshold. Silky, smooth midrange with a rich lower-midrange/upper-bass character. No mechanical issues or surround degradation found in a 20-year-old pair, and a second unit measured within about 1-1.5dB of the first, suggesting good long-term consistency for the design.
Cons: Manufacturer-spec sensitivity of 93dB runs about 3-4dB optimistic versus the measured 89.4dB average. Bass output drops off fairly quickly below about 50Hz in-room (F3 53Hz, F10 37Hz), so a subwoofer is needed for real low-end extension. Resonances show up around 170Hz, 220Hz, and 350Hz. On-axis, the lower treble can sound a bit bright or sibilant when the speaker is aimed directly at the listener; toeing out about 10-15° (rather than the more extreme 30°) gave the best balance, and some sidewall acoustic absorption further tamed a 4-5kHz peak. Placed close to the rear wall, bass gets boomy - pulling the speakers out about a foot resolves most of it, with roughly 1.5 feet from the wall as a good compromise between bass character and typical room aesthetics. Straying beyond about 25° above or below the mid-range axis introduces audible suckout. No longer in production, so it’s a used/secondhand purchase only. Discontinued.
Full Infinity Primus 360 review and specifications →
| Bass Extension (-10dB) | 37Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 53Hz (measured, Erin's Audio Corner) |
| Crossovers | 350Hz & 3.3kHz, 24dB/octave |
| Dimensions | 39"H x 8-1/8"W x 13-7/8"D (990 x 208 x 330mm) |
| Discontinued | Yes |
| Drivers | Two 6.5" mid-woofers, 4" mid-range, 0.75" dome tweeter |
| Frequency Response | 38Hz - 20kHz (±3dB, Manufacturer specified) |
| Impedance | 8 ohms nominal, 3.5 ohms minimum (measured, Erin's Audio Corner) |
| Recommended Power | 10-200W |
| Sensitivity | 89.4dB (measured, Erin's Audio Corner; 93dB manufacturer specified) |
| Weight | 48.5 lbs (48.5 lbs / 22 kg) each |
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