Short answer: the Radiant Acoustics Clarity 66 if sound quality matters most, the JBL HDI-3600 if price matters most. The Radiant Acoustics Clarity 66 ranks #5 of 71 floorstanding speakers at $7998. The JBL HDI-3600 ranks #28 at $3800, $4198 cheaper.
What the Radiant Acoustics Clarity 66 offers: ASR’s revised Spinorama measurement shows bass reaching 32.2Hz at -3dB and 27.8Hz at -6dB, giving substantial low-end weight without a subwoofer. The response spans 2.3dB from 300Hz to 5kHz, with preference scores of 5.10 standalone and 6.12 with an ideal subwoofer. The review’s exceptionally low bass distortion at ordinary levels complements that extension, while dual 6.5-inch Purifi woofers provide a strong foundation for full-range listening. Watch for: Vertical directivity is narrow and horizontal coverage is uneven, so listening height and placement affect tonal balance. Treble resonances and response irregularities keep it from reference-level neutrality. Spinorama’s modeled EQ improves the scores to 6.09 standalone and 6.99 with an ideal subwoofer, but those are corrected results, not stock performance. Measured sensitivity is 85.9dB at 2.83V/1m with a nominal 4-ohm load; use an amplifier comfortable driving 4 ohms. Distortion rises at very high playback levels.
What the JBL HDI-3600 offers: 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. Watch for: 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 HDI-1600, making it more audible. Narrow vertical sweet spot means careful listener-height positioning matters more than usual.
Buy the Radiant Acoustics Clarity 66 when sound quality outweighs the price for you, and the JBL HDI-3600 when the price outweighs sound quality instead.
Still deciding? The full Passive Home rankings cover every ranked option.
Specifications Side By Side
| Radiant Acoustics Clarity 66 | JBL HDI-3600 | |
|---|---|---|
| Price | $7,998 per pair | $3800 per pair |
| Ranked | #5 of 71 in Large Size Floorstanding Speakers | #28 of 71 in Large Size Floorstanding Speakers |
| Bass Extension (-3dB) | 32.2Hz (measured, Audio Science Review) | 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) |
| Bass Extension (-10dB) | 24.4Hz (measured, Audio Science Review) | 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) |
| Sensitivity | 85.9dB (2.83V/1m, measured, Audio Science Review; 86dB manufacturer specified) | 89.5dB (2.83V/1m, measured, Audio Science Review) |
| Drivers | Custom waveguide-loaded tweeter with beam-expansion fins, 2x 6.5" Purifi USHINDI aluminum-cone woofers | 2410H-2 1" compression driver, 3x 6.5" Advanced Aluminum Matrix woofers |
| Dimensions | 40.4"H x 8.7"W x 14"D (1025 x 222 x 355 mm) | 40.5"H x 10.2"W x 13.5"D (1029 x 260 x 343 mm) |
| Weight | 101.4 lbs (46 kg) each | 61.7 lbs (28 kg) each |
| Impedance | 4 ohms nominal | 4 ohms nominal |
| Crossover Frequency | 2.4kHz | - |
| Woofer Cabinet | ported, large rear port | ported, dual rear-firing |
| Spinorama Preference Score | 5.10 | - |
| Spinorama Preference Score with Perfect Sub | 6.12 | - |
| Frequency Response | - | 38Hz - 30kHz (+/-3dB) (Manufacturer specified) |
Related Speaker Comparisons
More worthwhile head-to-heads for Radiant Acoustics Clarity 66:
- Radiant Acoustics Clarity 66 vs KEF Blade Two Meta
- Radiant Acoustics Clarity 66 vs MoFi SourcePoint V10 Master Edition
- Radiant Acoustics Clarity 66 vs MoFi SourcePoint 888
- Radiant Acoustics Clarity 66 vs Ascend Acoustics ELX Ribbon Tower
- Radiant Acoustics Clarity 66 vs Revel F328Be
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.
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The Two Speakers In Full
Radiant Acoustics Clarity 66: $7,998 per pair Radiant Acoustics eBay
Pros: ASR’s revised Spinorama measurement shows bass reaching 32.2Hz at -3dB and 27.8Hz at -6dB, giving substantial low-end weight without a subwoofer. The response spans 2.3dB from 300Hz to 5kHz, with preference scores of 5.10 standalone and 6.12 with an ideal subwoofer. The review’s exceptionally low bass distortion at ordinary levels complements that extension, while dual 6.5-inch Purifi woofers provide a strong foundation for full-range listening. Measured bass extension of 32.2Hz (-3dB), with a measured sensitivity of 85.9dB.
Cons: Vertical directivity is narrow and horizontal coverage is uneven, so listening height and placement affect tonal balance. Treble resonances and response irregularities keep it from reference-level neutrality. Spinorama’s modeled EQ improves the scores to 6.09 standalone and 6.99 with an ideal subwoofer, but those are corrected results, not stock performance. Measured sensitivity is 85.9dB at 2.83V/1m with a nominal 4-ohm load; use an amplifier comfortable driving 4 ohms. Distortion rises at very high playback levels.
Full Radiant Acoustics Clarity 66 review and specifications →
| Bass Extension (-10dB) | 24.4Hz (measured, Audio Science Review) |
|---|---|
| Bass Extension (-3dB) | 32.2Hz (measured, Audio Science Review) |
| Crossover Frequency | 2.4kHz |
| Dimensions | 40.4"H x 8.7"W x 14"D (1025 x 222 x 355 mm) |
| Drivers | Custom waveguide-loaded tweeter with beam-expansion fins, 2x 6.5" Purifi USHINDI aluminum-cone woofers |
| Impedance | 4 ohms nominal |
| Sensitivity | 85.9dB (2.83V/1m, measured, Audio Science Review; 86dB manufacturer specified) |
| Spinorama Preference Score | 5.10 |
| Spinorama Preference Score with Perfect Sub | 6.12 |
| Weight | 101.4 lbs (46 kg) each |
| Woofer Cabinet | ported, large rear port |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Radiant Acoustics Clarity 66 vs Ascend Acoustics ELX Ribbon Tower
- Radiant Acoustics Clarity 66 vs MoFi SourcePoint 888
- Radiant Acoustics Clarity 66 vs MoFi SourcePoint V10 Master Edition
- Radiant Acoustics Clarity 66 vs KEF Blade Two Meta
- Radiant Acoustics Clarity 66 vs Revel F328Be
- Radiant Acoustics Clarity 66 vs Revel F226Be
- Radiant Acoustics Clarity 66 vs JBL 4367
- Radiant Acoustics Clarity 66 vs Revel F228Be
- See all 23 comparisons
JBL HDI-3600: $3800 per pair Audioadvice eBay
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 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) |
| 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) |
| Weight | 61.7 lbs (28 kg) each |
| Woofer Cabinet | ported, dual rear-firing |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons