Short answer: the JBL HDI-3600. It ranks #58 of 188 floorstanding speakers by sound quality (rated 4.3/5) at $3,800 and is still sold new; the Infinity Primus 360 ranks #77 (rated 4.2/5) and is discontinued, so it is only an option used.
The case for the JBL HDI-3600: CEA2034 spinorama shows a fairly even on-axis response and flat overall frequency response, with high 90dB sensitivity and very low distortion through the midrange. The tradeoff: A wide shelving-down above 2kHz affects the in-room response, and vertical dispersion is a bigger issue than horizontal: the reviewer noted the dip is wider here than on the smaller JBL HDI-1600, making it more audible.
The Infinity Primus 360 is the deeper-bass choice. Its bass reaches about 53Hz before falling 3dB, against 78Hz for the JBL HDI-3600. Watch for: Manufacturer-spec sensitivity of 93dB runs about 3-4dB optimistic versus the measured 89.4dB average.
Buy the JBL HDI-3600. It is rated higher for sound quality and still sold new, while the Infinity Primus 360 is discontinued.
Want more options? Browse the full Passive Home rankings.
Specifications Side By Side
| JBL HDI-3600 | Infinity Primus 360 | |
|---|---|---|
| Price | $3800 per pair | $650 per pair Discontinued |
| Ranked | #58 of 188 in Large Size Floorstanding Speakers | #77 of 188 in Large Size Floorstanding Speakers |
| Bass Extension (-3dB) | 78Hz - the on-axis curve also shows an unusual step/dip around 40-55Hz that may be a near-field-scan artifact for this tower (measured, Audio Science Review) | 53Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-10dB) | 62Hz - the on-axis curve also shows an unusual step/dip around 40-55Hz that may be a near-field-scan artifact for this tower (measured, Audio Science Review) | 37Hz (measured, Erin’s Audio Corner) |
| Sensitivity | 89.5dB (2.83V/1m, measured, Audio Science Review) | 89.4dB (measured, Erin’s Audio Corner; 93dB manufacturer specified) |
| Impedance | 4 ohms nominal | 8 ohms nominal, 3.5 ohms minimum (measured, Erin’s Audio Corner) |
| Frequency Response | 38Hz - 30kHz (+/-3dB) (Manufacturer specified) | 38Hz - 20kHz (±3dB, Manufacturer specified) |
| Drivers | 2410H-2 1” compression driver, 3x 6.5” Advanced Aluminum Matrix woofers | Two 6.5” mid-woofers, 4” mid-range, 0.75” dome tweeter |
| Weight | 61.7 lbs (28 kg) each | 48.5 lbs (22 kg) each |
| Dimensions | 40.5”H x 10.2”W x 13.5”D (1029 x 260 x 343 mm) | 39” x 8.2” x 13” (990 x 208 x 330 mm) |
| Woofer Cabinet | ported, dual rear-firing | - |
| Spinorama Preference Score | 4.64 (spinorama.org) | 4.97 |
| Spinorama Preference Score with Perfect Sub | 6.95 (spinorama.org) | 7.10 |
| DIY Kit | No | No |
| Crossover Frequency | - | 350Hz & 3.3kHz, 24dB/octave |
| Recommended Power | - | 10-200W |
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The Two Speakers In Full
JBL HDI-3600: $3800 per pair Audio Advice eBay
Same family: the JBL HDI-1600 (bookshelf, rated 4.2/5), the JBL HDI-3800 (larger floorstanding, ranked higher, rated 4.5/5) and the JBL HDI-4500 (center, rated 3.7/5).
Pros: CEA2034 spinorama shows a fairly even on-axis response and flat overall frequency response, with high 90dB sensitivity and very low distortion through the midrange. Triple 6.5” Advanced Aluminum Matrix woofers and a 1” compression driver in JBL’s HDI waveguide. Measured bass extension of 78Hz (-3dB), with a measured sensitivity of 89.5dB.
Cons: A wide shelving-down above 2kHz affects the in-room response, and vertical dispersion is a bigger issue than horizontal: the reviewer noted the dip is wider here than on the smaller JBL HDI-1600, making it more audible. Narrow vertical sweet spot means careful listener-height positioning matters more than usual.
Full JBL HDI-3600 review and specifications →
| Bass Extension (-10dB) | 62Hz - the on-axis curve also shows an unusual step/dip around 40-55Hz that may be a near-field-scan artifact for this tower (measured, Audio Science Review) |
|---|---|
| Bass Extension (-3dB) | 78Hz - the on-axis curve also shows an unusual step/dip around 40-55Hz that may be a near-field-scan artifact for this tower (measured, Audio Science Review) |
| DIY Kit | No |
| Dimensions | 40.5”H x 10.2”W x 13.5”D (1029 x 260 x 343 mm) |
| Drivers | 2410H-2 1” compression driver, 3x 6.5” Advanced Aluminum Matrix woofers |
| Frequency Response | 38Hz - 30kHz (+/-3dB) (Manufacturer specified) |
| Impedance | 4 ohms nominal |
| Sensitivity | 89.5dB (2.83V/1m, measured, Audio Science Review) |
| Spinorama Preference Score | 4.64 (spinorama.org) |
| Spinorama Preference Score with Perfect Sub | 6.95 (spinorama.org) |
| Weight | 61.7 lbs (28 kg) each |
| Woofer Cabinet | ported, dual rear-firing |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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Infinity Primus 360: $650 per pair Discontinued eBay
Same family: the Infinity Primus 150 (bookshelf, rated 3.4/5).
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 |
- Reviews, Comparisons and Sound Samples
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