Short answer: the Infinity Primus 360. It ranks #32 of 56 floorstanding speakers by sound quality at $650; the KEF Q11 Meta ranks #36 and costs $1249.99, so there is not much of a tradeoff to weigh.
On the Infinity Primus 360 side: 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. Set against that: Manufacturer-spec sensitivity of 93dB runs about 3-4dB optimistic versus the measured 89.4dB average.
What the KEF Q11 Meta gets right: Three-way tower design with a coaxial layout: a 3/4” aluminum dome tweeter (with KEF’s Metamaterial Absorption Technology behind it) mounted at the center of a 4” mid-range, plus three 6.5” bass drivers. The catch: Genuinely dark-sounding on raw on-axis measurement, and needs a typical room with sidewall reflections (within about 6 feet/2 meters) to sound properly neutral - in a large room with little sidewall interaction.
Buy the Infinity Primus 360. It ranks higher for sound quality than the KEF Q11 Meta and costs less, so there is no real case for the other one.
Specifications Side By Side
| Infinity Primus 360 | KEF Q11 Meta | |
|---|---|---|
| Price | $650.00 Discontinued | $1,249.99 |
| Ranked | #32 of 56 in Large Size Floorstanding Speakers | #36 of 56 in Large Size Floorstanding Speakers |
| Bass Extension (-10dB) | 37Hz (measured, Erin’s Audio Corner) | 29Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-3dB) | 53Hz (measured, Erin’s Audio Corner) | 60Hz (measured, Erin’s Audio Corner) |
| Drivers | Two 6.5" mid-woofers, 4" mid-range, 0.75" dome tweeter | 25mm tweeter + dual 165mm drivers |
| Sensitivity | 89.4dB (measured, Erin’s Audio Corner; 93dB manufacturer specified) | 88.6dB (measured, Erin’s Audio Corner) |
| Impedance | 8 ohms nominal, 3.5 ohms minimum (measured, Erin’s Audio Corner) | 4 ohms nominal (3.2 ohms minimum, measured, Erin’s Audio Corner) |
| Discontinued | Yes | - |
| Dimensions | 39"H x 8-1/8"W x 13-7/8"D (990 x 208 x 330mm) | 43.8"H x 12.5"W x 15"D (1112.8 x 317.5 x 381.0 mm) |
| Weight | 48.5 lbs (48.5 lbs / 22 kg) each | 106.9 lbs / 48.5 kg |
| Frequency Response | 38Hz - 20kHz (±3dB, Manufacturer specified) | - |
| Crossovers | 350Hz & 3.3kHz, 24dB/octave | - |
| Recommended Power | 10-200W | - |
| Woofer Cabinet | - | ported, rear |
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The Two Speakers In Full
Infinity Primus 360: $650.00 Discontinued
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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KEF Q11 Meta: $1,249.99 Amazon
Pros: Three-way tower design with a coaxial layout: a 3/4” aluminum dome tweeter (with KEF’s Metamaterial Absorption Technology behind it) mounted at the center of a 4” mid-range, plus three 6.5” bass drivers. Extremely linear estimated in-room response when placed correctly, thanks to a deliberately declining on-axis response paired with well-controlled directivity - a technically sound design philosophy, even though it reads as “dark” in raw anechoic on-axis measurements. In-room bass extension to about 40-50Hz when placed near a wall, thanks to extended bass-shelf tuning. Sounds excellent whether pointed directly at the listener or toed out a full 30° parallel to the back wall - unusually flexible placement. More vertical listening leeway than standard non-coaxial two-way designs, thanks to the coincident tweeter/midrange. Distortion looks good at both 86dB and 96dB, and multitone distortion holds up well too. Comes with a plinth/outrigger kit for stability given its floorstanding height (about 43-44”).
Cons: Genuinely dark-sounding on raw on-axis measurement, and needs a typical room with sidewall reflections (within about 6 feet/2 meters) to sound properly neutral - in a large room with little sidewall interaction, it may sound too dull for some listeners. Must be placed close to a rear wall (about 1 foot) to get proper bass - pulling it out to the “standard” 3-foot audiophile recommendation causes bass output to drop off noticeably. Horizontal radiation of about ±50° is narrower than the reviewer’s preferred ±60°, giving a slightly less enveloping soundstage than some rivals. Notably darker than sibling KEF models in the same product family - measures 2-5dB less top-end energy than the R3 Meta and a few dB less than the Q Concerto Meta. Minor lingering resonances appear in burst decay measurements between 500Hz-1kHz. The tweeter shows some strain at very high output volumes, a limitation the reviewer notes is common even among more budget-friendly speakers generally.
Full KEF Q11 Meta review and specifications →
| Bass Extension (-10dB) | 29Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 60Hz (measured, Erin's Audio Corner) |
| Dimensions | 43.8"H x 12.5"W x 15"D (1112.8 x 317.5 x 381.0 mm) |
| Drivers | 25mm tweeter + dual 165mm drivers |
| Impedance | 4 ohms nominal (3.2 ohms minimum, measured, Erin's Audio Corner) |
| Sensitivity | 88.6dB (measured, Erin's Audio Corner) |
| Weight | 106.9 lbs / 48.5 kg |
| Woofer Cabinet | ported, rear |
As an eBay Partner, we may be compensated if you make a purchase.
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