Short answer: the Infinity Primus 360. It ranks #30 of 54 floorstanding speakers by sound quality at $650; the Monolith Encore T6 ranks #38 and costs $800, so there is not much of a tradeoff to weigh.
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… Watch for: Manufacturer-spec sensitivity of 93dB runs about 3-4dB optimistic versus the measured 89.4dB average.
What the Monolith Encore T6 offers: 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 Infinity Primus 360. It ranks higher for sound quality than the Monolith Encore T6 and costs less, so there is no real case for the other one.
Specifications Side By Side
| Infinity Primus 360 | Monolith Encore T6 | |
|---|---|---|
| Price | $650.00 Discontinued | $800/pair |
| Ranked | #30 of 54 in Large Size Floorstanding Speakers | #38 of 54 in Large Size Floorstanding Speakers |
| Bass Extension (-10dB) | 37Hz (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 |
| Discontinued | Yes | - |
| Dimensions | 39"H x 8-1/8"W x 13-7/8"D (990 x 208 x 330mm) | 40H x 7.9W x 13.8D inches |
| Weight | 48.5 lbs (48.5 lbs / 22 kg) each | 49.2lb each |
| Frequency Response | 38Hz - 20kHz (±3dB, Manufacturer specified) | - |
| Crossovers | 350Hz & 3.3kHz, 24dB/octave | - |
| Recommended Power | 10-200W | - |
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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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Monolith Encore T6: $800/pair Amazon Monoprice
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.
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 (-3dB) | ~68Hz (measured, Erin's Audio Corner) |
|---|---|
| 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) |
| Weight | 49.2lb each |
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