Short answer: the Definitive Technology BP-9020. It ranks #29 of 54 floorstanding speakers by sound quality at $500; the Infinity Primus 360 ranks #30 and costs $650, so there is not much of a tradeoff to weigh.
What the Definitive Technology BP-9020 offers: Integrated powered 8” side-firing subwoofer with a 150-watt Class D amplifier provides exceptional sub-bass extension down to an F3 of 35Hz and F10 of 29Hz without requiring a standalone subwoofer enclosure. Watch for: Significant high-frequency boost creates notable treble brightness and noticeable sibilance on vocal s-sounds.
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.
Buy the Definitive Technology BP-9020. It ranks higher for sound quality than the Infinity Primus 360 and costs less, so there is no real case for the other one.

Specifications Side By Side
| Definitive Technology BP-9020 | Infinity Primus 360 | |
|---|---|---|
| Price | $500.00 Discontinued | $650.00 Discontinued |
| Ranked | #29 of 54 in Large Size Floorstanding Speakers | #30 of 54 in Large Size Floorstanding Speakers |
| Bass Extension (-10dB) | 29Hz (measured, Erin’s Audio Corner) | 37Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-3dB) | 35Hz (measured, Erin’s Audio Corner) | 53Hz (measured, Erin’s Audio Corner) |
| Dimensions | 35.3"H x 11"W x 13"D (895.4 x 279.4 x 330.2 mm) | 39"H x 8-1/8"W x 13-7/8"D (990 x 208 x 330mm) |
| Discontinued | Yes | Yes |
| Impedance | 8 ohms nominal | 8 ohms nominal, 3.5 ohms minimum (measured, Erin’s Audio Corner) |
| Sensitivity | 87.7dB (measured average, Erin’s Audio Corner) | 89.4dB (measured, Erin’s Audio Corner; 93dB manufacturer specified) |
| Drivers | 1 in. annealed aluminum dome tweeter, two 3.5 in. BDSS midrange (front), one 3.5 in. BDSS midrange (rear), 8 in. powered subwoofer | Two 6.5" mid-woofers, 4" mid-range, 0.75" dome tweeter |
| Weight | 30 lbs / 13.6 kg each | 48.5 lbs (48.5 lbs / 22 kg) each |
| Woofer Cabinet | ported, slot | - |
| 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
Definitive Technology BP-9020: $500.00 Discontinued
Pros: Integrated powered 8” side-firing subwoofer with a 150-watt Class D amplifier provides exceptional sub-bass extension down to an F3 of 35Hz and F10 of 29Hz without requiring a standalone subwoofer enclosure. Forward-Focused Bipolar Array technology (dual 3.5” front midrange drivers + 1” annealed aluminum dome tweeter, plus a 3.5” rear-firing midrange driver) creates a remarkably wide, spacious soundstage with broad room envelopment. On-axis frequency response stays smooth and relatively neutral when listened to directly aligned with the tweeter. Measured average sensitivity of 87.7dB SPL (2.83V/1m) allows comfortable drive from standard multi-channel receivers.
Cons: Significant high-frequency boost creates notable treble brightness and noticeable sibilance on vocal s-sounds. Bipolar rear driver radiation creates a diffuse soundstage that compromises razor-sharp imaging focus and pinpoint instrument placement. DSP-based internal limiter aggressively compresses output below 80Hz at higher listening levels, causing lower mid-bass and sub-bass impact to diminish as volume increases. Midrange clarity shows slight ‘cuppiness’ and upper-frequency directivity irregularities due to front/rear driver interaction. Discontinued.
Full Definitive Technology BP-9020 review and specifications →
| Bass Extension (-10dB) | 29Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 35Hz (measured, Erin's Audio Corner) |
| Dimensions | 35.3"H x 11"W x 13"D (895.4 x 279.4 x 330.2 mm) |
| Discontinued | Yes |
| Drivers | 1 in. annealed aluminum dome tweeter, two 3.5 in. BDSS midrange (front), one 3.5 in. BDSS midrange (rear), 8 in. powered subwoofer |
| Impedance | 8 ohms nominal |
| Sensitivity | 87.7dB (measured average, Erin's Audio Corner) |
| Weight | 30 lbs / 13.6 kg each |
| Woofer Cabinet | ported, slot |
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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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