Short answer: the Monolith Encore T6, if you are buying new. The Infinity Primus 360 ranks higher than it (#40 vs #47 of 73 floorstanding speakers, 4.2/5 vs 4.0/5) but is discontinued, so only consider it used; the Monolith Encore T6 is still sold new at $800.
What the Infinity Primus 360 does well: 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. The tradeoff: Manufacturer-spec sensitivity of 93dB runs about 3-4dB optimistic versus the measured 89.4dB average.
What the Monolith Encore T6 does well: Three 6.5-inch pulp-cone drivers provide more displacement and cleaner cinema output than the B6, with good compression behavior at normal levels. Watch for: Despite its size, Erin measured F3 around 68Hz, so the tower does not eliminate the need for a subwoofer.
Buy the Monolith Encore T6 new; the Infinity Primus 360 is no longer sold new, so it only makes sense as a used find.
Want more options? Browse the full Passive Home rankings.
Specifications Side By Side
| Infinity Primus 360 | Monolith Encore T6 | |
|---|---|---|
| Price | $650.00 per pair Discontinued | $800 per pair |
| Ranked | #40 of 73 in Large Size Floorstanding Speakers | #47 of 73 in Large Size Floorstanding Speakers |
| Bass Extension (-10dB) | 37Hz (measured, Erin’s Audio Corner) | 31.1Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-3dB) | 53Hz (measured, Erin’s Audio Corner) | ~68Hz (measured, Erin’s Audio Corner) |
| Drivers | Two 6.5” mid-woofers, 4” mid-range, 0.75” dome tweeter | Three 6.5-inch pulp woofers; 25mm waveguided silk dome |
| Sensitivity | 89.4dB (measured, Erin’s Audio Corner; 93dB manufacturer specified) | 87.8dB/2.83V/1m (manufacturer) |
| Impedance | 8 ohms nominal, 3.5 ohms minimum (measured, Erin’s Audio Corner) | 4 ohms nominal |
| Dimensions | 39” x 8.2” x 13” (990 x 208 x 330 mm) | 40H x 7.9W x 13.8D inches |
| Weight | 48.5 lbs (22 kg) each | 49.2 lbs (22.3 kg) each |
| Frequency Response | 38Hz - 20kHz (±3dB, Manufacturer specified) | - |
| Crossover Frequency | 350Hz & 3.3kHz, 24dB/octave | - |
| Recommended Power | 10-200W | - |
| Spinorama Preference Score | 4.97 | 4.57 |
| Spinorama Preference Score with Perfect Sub | 7.10 | 6.45 |
| DIY Kit | No | No |
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The Two Speakers In Full
Infinity Primus 360: $650.00 per pair 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. Measured bass extension of 53Hz (-3dB), with a measured sensitivity of 89.4dB.
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.
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) |
| Crossover Frequency | 350Hz & 3.3kHz, 24dB/octave |
| DIY Kit | No |
| Dimensions | 39” x 8.2” x 13” (990 x 208 x 330 mm) |
| 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) |
| Spinorama Preference Score | 4.97 |
| Spinorama Preference Score with Perfect Sub | 7.10 |
| Weight | 48.5 lbs (22 kg) each |
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Monolith Encore T6: $800 per pair Amazon Monoprice eBay
Pros: Three 6.5-inch pulp-cone drivers provide more displacement and cleaner cinema output than the B6, with good compression behavior at normal levels. Erin found the revised waveguided tweeter’s horizontal radiation consistent enough for predictable EQ, while the gloss-capped, heavily braced 49lb cabinet feels far above its price. The tower can produce useful midbass impact when crossed to a subwoofer. Measured bass extension of ~68Hz (-3dB).
Cons: Despite its size, Erin measured F3 around 68Hz, so the tower does not eliminate the need for a subwoofer. The native response needs equalization: crossover-region unevenness and excess top-octave energy prevent a fully neutral presentation. The four-ohm load and low-frequency phase angle warrant a robust amplifier, and the tall multi-driver array creates a narrower vertical listening window than a compact two-way.
Full Monolith Encore T6 review and specifications →
| Bass Extension (-10dB) | 31.1Hz (measured, Erin’s Audio Corner) |
|---|---|
| Bass Extension (-3dB) | ~68Hz (measured, Erin’s Audio Corner) |
| DIY Kit | No |
| Dimensions | 40H x 7.9W x 13.8D inches |
| Drivers | Three 6.5-inch pulp woofers; 25mm waveguided silk dome |
| Impedance | 4 ohms nominal |
| Sensitivity | 87.8dB/2.83V/1m (manufacturer) |
| Spinorama Preference Score | 4.57 |
| Spinorama Preference Score with Perfect Sub | 6.45 |
| Weight | 49.2 lbs (22.3 kg) each |
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- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons