Short answer: the JBL HDI-3800 for better sound quality, the Infinity Primus 360 for the lower price. The JBL HDI-3800 ranks #7 of 71 floorstanding speakers at $5000. The Infinity Primus 360 ranks #40 at $650, $4350 cheaper.
What the JBL HDI-3800 offers: 2410H-2 1” Teonex compression driver matched to a custom High-Definition Imaging (HDI) horn geometry achieves exceptional horizontal directivity control, high output capability, and effortless transient response. Triple 8” Advanced Aluminum Matrix woofers deliver deep, authoritative bass extension down to an F3 of 37Hz and F10 of 28Hz with minimal low-frequency compression. Outstanding sensitivity (92dB SPL at 2.83V/1m) and ultra-low THD/multitone distortion allow extremely high undistorted SPL output in large home theater spaces. Watch for: On-axis frequency response features a narrow upper-frequency elevation around 8-10kHz, performing noticeably smoother when toed out 10-20° off-axis. Vertical directivity handoff across the triple woofer layout creates vertical soundstage height tilt depending on listening distance and ear height. Minimum impedance dips to 3.8 ohms, requiring high-current amplifier stability. Substantial cabinet dimensions and 38kg weight require significant room real estate.
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 JBL HDI-3800 if sound quality matters more than the price. Buy the Infinity Primus 360 if the price matters more than sound quality.
Specifications Side By Side
| JBL HDI-3800 | Infinity Primus 360 | |
|---|---|---|
| Price | $5,000.00 Discontinued | $650.00 Discontinued |
| Ranked | #7 of 71 in Large Size Floorstanding Speakers | #40 of 71 in Large Size Floorstanding Speakers |
| Bass Extension (-10dB) | 28Hz (measured, Erin’s Audio Corner) | 37Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-3dB) | 37Hz (measured, Erin’s Audio Corner) | 53Hz (measured, Erin’s Audio Corner) |
| Dimensions | 43.3"H x 11.8"W x 16.4"D (1100.5 x 300.0 x 417.8 mm) | 39"H x 8-1/8"W x 13-7/8"D (990 x 208 x 330mm) |
| Discontinued | Yes | Yes |
| Impedance | 4 ohms nominal (3.8 ohms minimum, measured by Erin’s Audio Corner) | 8 ohms nominal, 3.5 ohms minimum (measured, Erin’s Audio Corner) |
| Sensitivity | 92dB (measured average, Erin’s Audio Corner) | 89.4dB (measured, Erin’s Audio Corner; 93dB manufacturer specified) |
| Drivers | 1 in. 2410H-2 Teonex compression driver with HDI horn, triple 8 in. Advanced Aluminum Matrix cone woofers | Two 6.5" mid-woofers, 4" mid-range, 0.75" dome tweeter |
| Weight | 83.8 lbs / 38.0 kg each | 48.5 lbs (48.5 lbs / 22 kg) each |
| Woofer Cabinet | ported, rear | - |
| 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
JBL HDI-3800: $5,000.00 Discontinued eBay
Pros: 2410H-2 1” Teonex compression driver matched to a custom High-Definition Imaging (HDI) horn geometry achieves exceptional horizontal directivity control, high output capability, and effortless transient response. Triple 8” Advanced Aluminum Matrix woofers deliver deep, authoritative bass extension down to an F3 of 37Hz and F10 of 28Hz with minimal low-frequency compression. Outstanding sensitivity (92dB SPL at 2.83V/1m) and ultra-low THD/multitone distortion allow extremely high undistorted SPL output in large home theater spaces.
Cons: On-axis frequency response features a narrow upper-frequency elevation around 8-10kHz, performing noticeably smoother when toed out 10-20° off-axis. Vertical directivity handoff across the triple woofer layout creates vertical soundstage height tilt depending on listening distance and ear height. Minimum impedance dips to 3.8 ohms, requiring high-current amplifier stability. Substantial cabinet dimensions and 38kg weight require significant room real estate. Discontinued.
Full JBL HDI-3800 review and specifications →
| Bass Extension (-10dB) | 28Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 37Hz (measured, Erin's Audio Corner) |
| Dimensions | 43.3"H x 11.8"W x 16.4"D (1100.5 x 300.0 x 417.8 mm) |
| Discontinued | Yes |
| Drivers | 1 in. 2410H-2 Teonex compression driver with HDI horn, triple 8 in. Advanced Aluminum Matrix cone woofers |
| Impedance | 4 ohms nominal (3.8 ohms minimum, measured by Erin's Audio Corner) |
| Sensitivity | 92dB (measured average, Erin's Audio Corner) |
| Weight | 83.8 lbs / 38.0 kg each |
| Woofer Cabinet | ported, rear |
- Links
- Reviews, Comparisons and Sound Samples
- Erin’s Audio Corner: JBL HDI-3800 Floorstanding Speaker Review More from Erin’s Audio Corner →
- Erin’s Audio Corner: Choosing the Ultimate Speaker: JBL Studio 698 or HDI-3800?
- Erin’s Audio Corner Website JBL HDI-3800
- Erin’s Audio Corner Measurements (spinorama.org)
- Reddit Search for JBL HDI-3800 Review
- 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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