Short answer: the JBL HDI-3600. It ranks #23 of 59 floorstanding speakers by sound quality at $3800; the Klipsch Forte IV ranks #35 and costs $5499.98, so there is not much of a tradeoff to weigh.
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. 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.
What the Klipsch Forte IV gets right: Three-way heritage design: a 1” titanium tweeter and 1.75” compression driver for the midrange mated to a 12” woofer, plus a 15” passive radiator for extra bass reinforcement. The catch: Contrary to the classic Klipsch reputation for being forward and bright, this model is actually somewhat recessed in the 1.5-4kHz “presence” region, which can make some tracks sound dull or lacking in detail.
Buy the JBL HDI-3600. It ranks higher for sound quality than the Klipsch Forte IV and costs less, so there is no real case for the other one.
Specifications Side By Side
| JBL HDI-3600 | Klipsch Forte IV | |
|---|---|---|
| Price | $3800 | $5,499.98 |
| Ranked | #23 of 59 in Large Size Floorstanding Speakers | #35 of 59 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) | 82Hz (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) | 39Hz (measured, Erin’s Audio Corner) |
| Sensitivity | 89.5dB (2.83V/1m, measured, Audio Science Review) | 93.8dB (measured average, Erin’s Audio Corner; manufacturer rates 99dB in-room / ~94dB anechoic) |
| Impedance | 4 ohms nominal | 8 ohms |
| Frequency Response | 38Hz - 30kHz (+/-3dB) (Manufacturer specified) | - |
| Drivers | 2410H-2 1" compression driver, 3x 6.5" Advanced Aluminum Matrix woofers | 1x 12" (305mm) fiber-composite woofer + 15" passive radiator, 1x 1.75" compression driver midrange on horn, 1x 1" titanium compression tweeter on horn |
| Weight | 61.7 lbs / 28 kg each | 117.3 lbs / 53.2 kg |
| Dimensions | 40.5"H x 10.2"W x 13.5"D (1029 x 260 x 343 mm) | 36"H x 16.5"W x 13"D (914.4 x 419.1 x 330.2 mm) |
| Woofer Cabinet | ported, dual rear-firing | passive radiator |
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The Two Speakers In Full
JBL HDI-3600: $3800 Audioadvice
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.
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 |
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Klipsch Forte IV: $5,499.98 Amazon Crutchfield
Pros: Three-way heritage design: a 1” titanium tweeter and 1.75” compression driver for the midrange mated to a 12” woofer, plus a 15” passive radiator for extra bass reinforcement. Genuinely resonance-free cabinet, a clear improvement over the notably boomy, resonant Heresy 4 in the same lineup. Surprisingly wide, expansive soundstage that beat both the Heresy 4 and a KEF LS50 Wireless 2 in direct comparison - images occasionally appeared several feet outside the physical speaker location. Deeper bass extension than the Heresy 4 (F3 of 82Hz, about 10Hz lower). Distortion measures well below 1% at 86dB and stays mostly within 1% even at 96dB. Comes as a factory-matched serial-numbered pair, backed by an unusually generous 10-year warranty. Mostly above 4 ohms impedance, so it’s compatible with AVRs, solid-state, or tube amplifiers. More neutral overall than other Klipsch models the reviewer has tested, making it a reasonable pick for listeners who already like the “Klipsch sound” but want something more balanced.
Cons: Contrary to the classic Klipsch reputation for being forward and bright, this model is actually somewhat recessed in the 1.5-4kHz “presence” region, which can make some tracks sound dull or lacking in detail. A peak around 6kHz reads as sibilant and “painful” when seated exactly on the tweeter axis; sitting a bit above that axis reduces it somewhat. Klipsch’s marketed 99dB sensitivity figure is an in-room rating that assumes 3-6dB of boundary gain - anechoic sensitivity measures closer to 94dB, which the manufacturer does disclose but can still mislead buyers comparing spec sheets. Radiation width isn’t consistent across all frequencies - a noticeable notch around 2-3kHz interrupts otherwise wide dispersion, which can cause a fundamental tone and its harmonics to image in slightly different places in the soundstage. Uses shallow low-pass crossover slopes (despite Klipsch’s steep-crossover marketing, which applies only to the high-pass side), likely contributing to some of the measured dips and possible cone-breakup artifacts. Some compression shows up around the midrange crossover point at very high output (102dB), though likely only audible at extreme volumes. At around $5,000/pair, a significant investment, and still needs a subwoofer for material extending below about 50Hz.
Full Klipsch Forte IV review and specifications →
| Bass Extension (-10dB) | 39Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 82Hz (measured, Erin's Audio Corner) |
| Dimensions | 36"H x 16.5"W x 13"D (914.4 x 419.1 x 330.2 mm) |
| Drivers | 1x 12" (305mm) fiber-composite woofer + 15" passive radiator, 1x 1.75" compression driver midrange on horn, 1x 1" titanium compression tweeter on horn |
| Impedance | 8 ohms |
| Sensitivity | 93.8dB (measured average, Erin's Audio Corner; manufacturer rates 99dB in-room / ~94dB anechoic) |
| Weight | 117.3 lbs / 53.2 kg |
| Woofer Cabinet | passive radiator |
As an eBay Partner, we may be compensated if you make a purchase.
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- Reviews, Comparisons and Sound Samples
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