Short answer: the Infinity Primus 360 for better sound quality, the Polk T50 for the lower price. The Infinity Primus 360 ranks #40 of 71 floorstanding speakers at $650. The Polk T50 ranks #55 at $209, $441 cheaper.
What the Polk T50 offers: Pretty deep bass for the price. Distortion at 86dB SPL/1m is reasonably controlled outside a narrow spike around 250Hz. The reviewer notes performance is “not too bad for a budget speaker” once the two main tonal issues are addressed with EQ. Watch for: 5dB peak at 1khz, 4dB bright top end from 11khz on up. Just okay vertical off axis. Impedance and phase show several resonances between 200Hz-1kHz, with a minimum impedance of 4.2 ohms. Distortion rises substantially at 96dB SPL/1m across the midrange, with repeated peaks between 100Hz-2kHz.
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 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. Watch for: 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.
Buy the Polk T50 if the price matters more than sound quality. Buy the Infinity Primus 360 if sound quality matters more than the price.
If sound quality matters at all to you, skip the Polk T50. It ranks near the bottom of the 71 floorstanding speakers, so look higher up the list instead.
Specifications Side By Side
| Polk T50 | Infinity Primus 360 | |
|---|---|---|
| Price | $209.00 | $650.00 Discontinued |
| Ranked | #55 of 71 in Large Size Floorstanding Speakers | #40 of 71 in Large Size Floorstanding Speakers |
| Bass Extension (-10dB) | 38Hz (measured, Audio Science Review) | 37Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-3dB) | 47Hz (measured, Audio Science Review) | 53Hz (measured, Erin’s Audio Corner) |
| Impedance | 4 ohms nominal (4.2 ohms minimum, measured by Audio Science Review) | 8 ohms nominal, 3.5 ohms minimum (measured, Erin’s Audio Corner) |
| Drivers | 2x 6.5" bi-laminate paper cone woofers, 1x 1" Terylene dome tweeter + 2x 8" passive bass radiators | Two 6.5" mid-woofers, 4" mid-range, 0.75" dome tweeter |
| Weight | 75.4 lbs / 34.2 kg | 48.5 lbs (48.5 lbs / 22 kg) each |
| Sensitivity | 86.3dB (2.83V/1m, measured by Audio Science Review) | 89.4dB (measured, Erin’s Audio Corner; 93dB manufacturer specified) |
| Dimensions | 40.4"H x 9.3"W x 12.5"D (1026.2 x 235.0 x 317.5 mm) | 39"H x 8-1/8"W x 13-7/8"D (990 x 208 x 330mm) |
| Woofer Cabinet | passive radiator | - |
| Discontinued | - | Yes |
| Frequency Response | - | 38Hz - 20kHz (±3dB, Manufacturer specified) |
| Crossovers | - | 350Hz & 3.3kHz, 24dB/octave |
| Recommended Power | - | 10-200W |
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Prices on this page were last checked August 25, 2026 at 6:19 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.
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The Two Speakers In Full
Polk T50: $209.00 Amazon eBay
Pros: Pretty deep bass for the price. Distortion at 86dB SPL/1m is reasonably controlled outside a narrow spike around 250Hz. The reviewer notes performance is “not too bad for a budget speaker” once the two main tonal issues are addressed with EQ.
Cons: 5dB peak at 1khz, 4dB bright top end from 11khz on up. Just okay vertical off axis. Impedance and phase show several resonances between 200Hz-1kHz, with a minimum impedance of 4.2 ohms. Distortion rises substantially at 96dB SPL/1m across the midrange, with repeated peaks between 100Hz-2kHz.
Full Polk T50 review and specifications →
| Bass Extension (-10dB) | 38Hz (measured, Audio Science Review) |
|---|---|
| Bass Extension (-3dB) | 47Hz (measured, Audio Science Review) |
| Dimensions | 40.4"H x 9.3"W x 12.5"D (1026.2 x 235.0 x 317.5 mm) |
| Drivers | 2x 6.5" bi-laminate paper cone woofers, 1x 1" Terylene dome tweeter + 2x 8" passive bass radiators |
| Impedance | 4 ohms nominal (4.2 ohms minimum, measured by Audio Science Review) |
| Sensitivity | 86.3dB (2.83V/1m, measured by Audio Science Review) |
| Weight | 75.4 lbs / 34.2 kg |
| Woofer Cabinet | passive radiator |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
Infinity Primus 360: $650.00 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.
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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