Short answer: the Ascend Acoustics ELX Ribbon Tower. It ranks #12 of 226 floorstanding speakers by sound quality, rated 4.6/5, at $5,698. The JBL HDI-3600 ranks #63, rated 4.3/5, at $3,800, $1,898 cheaper, a saving that is not big enough to make up the sound-quality gap.
The Ascend Acoustics ELX Ribbon Tower is the more accurate, deeper-bass choice. A RAAL 70-20xram ribbon tweeter and dual SEAS Excel aluminum woofers in a 3-way, 4-driver bamboo tower measure a genuine 38.7Hz extension point with a nearly flat on axis slope of 0.05dB per octave, one of the flattest measured towers we list. Its measured preference score, a predictor of how neutral it sounds, is 6.97 against 4.64 for the JBL HDI-3600. Its bass reaches about 38.7Hz before falling 3dB, against 78Hz for the JBL HDI-3600. The catch: Listening window smoothness measures a moderate 0.40 and on axis deviation runs 0.286dB average, both trailing the tighter figures posted by some of the passive AsciLab and Ascend bookshelf models in this same batch.
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. 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 JBL HDI-1600, making it more audible.
Buy the Ascend Acoustics ELX Ribbon Tower. It is rated higher for sound quality, and the $1,898 saving on the JBL HDI-3600 is not enough to make up the difference.
Want more options? Browse the full Passive Home rankings.
Specifications Side By Side
| Ascend Acoustics ELX Ribbon Tower | JBL HDI-3600 | |
|---|---|---|
| Price | $5,698 per pair | $3800 per pair |
| Ranked | #12 of 226 in Large Size Floorstanding Speakers | #63 of 226 in Large Size Floorstanding Speakers |
| Enclosure | ported | - |
| Drivers | RAAL 70-20xram ribbon tweeter, 6” SEAS Excel Curv midrange (sealed sub-chamber), 2x 6” SEAS Excel aluminum woofers | 2410H-2 1” compression driver, 3x 6.5” Advanced Aluminum Matrix woofers |
| Dimensions | 43”H x 7.5”W x 10.5”D (1092 x 190 x 267 mm) | 40.5”H x 10.2”W x 13.5”D (1029 x 260 x 343 mm) |
| Weight | 56 lbs (25.4 kg) each | 61.7 lbs (28 kg) each |
| Sensitivity | 87.5dB @ 2.83V/1m anechoic (manufacturer) | 89.5dB (2.83V/1m, measured, Audio Science Review) |
| Impedance | 8 ohms nominal | 4 ohms nominal |
| Power Handling | 400W continuous, 600W peak | - |
| Frequency Response | 36-27,000Hz +/-3dB anechoic (manufacturer) | 38Hz - 30kHz (+/-3dB) (Manufacturer specified) |
| Bass Extension (-3dB) | 38.7Hz (measured, spinorama.org vendor data) | 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) | 28.5Hz (measured, spinorama.org vendor data) | 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) |
| Warranty | 7 years parts and labor | - |
| Country | United States | - |
| Spinorama Preference Score | 6.97 | 4.64 (spinorama.org) |
| Spinorama Preference Score with Perfect Sub | 8.42 | 6.95 (spinorama.org) |
| DIY Kit | No | No |
| Woofer Cabinet | - | ported, dual rear-firing |
Frequency Response Compared
Both speakers’ spinorama measurements, overlaid. A flatter line is more neutral: peaks sound forward or harsh, dips sound recessed. Each curve is shifted so its average from 300 Hz to 3 kHz sits at 0 dB, so loudness differences between the two are removed and only the shape is compared. The two were measured by different sources, so small differences, especially in the bass, can come from the measurement setup rather than the speakers.
Measurement data: Ascend Acoustics ELX Ribbon Tower (measured by the manufacturer) and JBL HDI-3600 (measured by Audio Science Review), via spinorama.org.
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The Two Speakers In Full
Ascend Acoustics ELX Ribbon Tower: $5,698 per pair Ascend Acoustics $5,698 eBay
Same family: the Ascend Acoustics ELX Ribbon Horizon (center, rated 4.6/5).
Pros: A RAAL 70-20xram ribbon tweeter and dual SEAS Excel aluminum woofers in a 3-way, 4-driver bamboo tower measure a genuine 38.7Hz extension point with a nearly flat on axis slope of 0.05dB per octave, one of the flattest measured towers we list. The bass alignment Q of 0.62 keeps the low end well damped rather than peaky. Backed by a 7 year parts and labor warranty and hand assembled in Orange County, California, with each pair matched within +/-1.5dB. Measured bass extension of 38.7Hz (-3dB).
Cons: Listening window smoothness measures a moderate 0.40 and on axis deviation runs 0.286dB average, both trailing the tighter figures posted by some of the passive AsciLab and Ascend bookshelf models in this same batch. At $5698/pair it is Ascend’s most expensive tower, well above the Titan dome tweeter version of the same cabinet. The manufacturer’s own claimed sensitivity (87.5dB) runs nearly 1.5dB higher than the independently measured average (86.1dB), worth accounting for when matching an amplifier.
Full Ascend Acoustics ELX Ribbon Tower review and specifications →
| Bass Extension (-10dB) | 28.5Hz (measured, spinorama.org vendor data) |
|---|---|
| Bass Extension (-3dB) | 38.7Hz (measured, spinorama.org vendor data) |
| Country | United States |
| DIY Kit | No |
| Dimensions | 43”H x 7.5”W x 10.5”D (1092 x 190 x 267 mm) |
| Drivers | RAAL 70-20xram ribbon tweeter, 6” SEAS Excel Curv midrange (sealed sub-chamber), 2x 6” SEAS Excel aluminum woofers |
| Enclosure | ported |
| Frequency Response | 36-27,000Hz +/-3dB anechoic (manufacturer) |
| Impedance | 8 ohms nominal |
| Power Handling | 400W continuous, 600W peak |
| Sensitivity | 87.5dB @ 2.83V/1m anechoic (manufacturer) |
| Spinorama Preference Score | 6.97 |
| Spinorama Preference Score with Perfect Sub | 8.42 |
| Warranty | 7 years parts and labor |
| Weight | 56 lbs (25.4 kg) each |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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- Ascend Acoustics ELX Ribbon Tower vs MoFi SourcePoint 888
- Ascend Acoustics ELX Ribbon Tower vs JBL 4367
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JBL HDI-3600: $3800 per pair Audio Advice $3800 eBay
Same family: the JBL HDI-1600 (bookshelf, rated 4.2/5), the JBL HDI-3800 (larger floorstanding, ranked higher, rated 4.5/5), the JBL HDI-4500 (center, rated 3.7/5) and the JBL HDI-1200P (subwoofer, rated 3.9/5).
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 →
| Released | Jun 2020 (6 years ago) |
|---|---|
| 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