The Infinity Primus 360 ranks #40 out of 71 total Large Size Floorstanding Speakers for sound quality. See all Passive Home rankings for every top pick.
Brand: Infinity
Prices on this page were last checked September 16, 2026 at 12:41 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.
As an eBay Partner, we may be compensated if you make a purchase.
#40 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. Discontinued.
How it compares: Just above it: Definitive Technology BP-9020 - $150 cheaper, 1.7Hz lower bass extension (-3dB). Just below it: Klipsch Forte IV - $4850 more, 4.4Hz higher bass extension (-3dB).
| 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 |
| Dimensions | 39" x 8.2" x 13" (990 x 208 x 330 mm) |
| 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) |
| Spinorama Preference Score | 4.05 |
| Spinorama Preference Score with Perfect Sub | 6.19 |
| Weight | 48.5 lbs (22 kg) each |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Infinity Primus 360 vs Definitive Technology BP-9020
- Infinity Primus 360 vs Klipsch Forte IV
- Infinity Primus 360 vs Linkwitz Lab LXmini
- Infinity Primus 360 vs Klipsch Heresy IV
- Infinity Primus 360 vs Polk Reserve R500
- Infinity Primus 360 vs ELAC Debut 3.0 DF63
- Infinity Primus 360 vs KEF Q11 Meta
- Infinity Primus 360 vs PSB Imagine T65
- Infinity Primus 360 vs Q Acoustics 5040
- Infinity Primus 360 vs Klipsch RP-5000F II
- Infinity Primus 360 vs Polk Audio Reserve R700
- Infinity Primus 360 vs SVS Ultra Evolution Pinnacle
- Infinity Primus 360 vs Monolith Encore T6
- Infinity Primus 360 vs Emotiva Airmotiv T2+
- Infinity Primus 360 vs Klipsch RP-8000F II
- Infinity Primus 360 vs JBL HDI-3600
- Infinity Primus 360 vs Dynaudio Emit 30
- Infinity Primus 360 vs KEF R11 Meta
- Infinity Primus 360 vs Polk T50
- Infinity Primus 360 vs Revel Concerta2 F35
- Infinity Primus 360 vs Focal Aria Evo X N°2
- Infinity Primus 360 vs Revel F206
- Infinity Primus 360 vs JBL Studio 698
- Infinity Primus 360 vs Magnepan LRS+
- Infinity Primus 360 vs Revel F228Be
- Infinity Primus 360 vs Revel F208
- Infinity Primus 360 vs Focal Chora 816
- Infinity Primus 360 vs KEF Reference 203
- Infinity Primus 360 vs Revel F226Be
- Infinity Primus 360 vs KEF R5
- Infinity Primus 360 vs JBL HDI-3800