Short answer: the Klipsch Heresy IV for efficiency, the Q Acoustics 5040 for bass. The Heresy IV measures 94.5dB/2.83V/1m sensitivity, well below Klipsch’s 99dB claim but still excellent, and Erin measured a 77Hz F3 with response rolling away near 100Hz in-room, so a subwoofer is required. The 5040’s C3 profile keeps the midrange smooth, but a mid-bass scoop around 200Hz leaves it roughly 6dB below the mean SPL.
Buy the Q Acoustics 5040. It is rated higher for sound quality than the Klipsch Heresy IV and costs less, so only choose the other one for a particular feature it does better.
Still deciding? The full Passive Home rankings cover every ranked option.
Specifications Side By Side
| Q Acoustics 5040 | Klipsch Heresy IV | |
|---|---|---|
| Price | $2,472.98 per pair | $3,198 per pair |
| Ranked | #41 of 74 in Large Size Floorstanding Speakers | #72 of 74 in Large Size Floorstanding Speakers |
| Bass Extension (-10dB) | 39Hz (measured, Erin’s Audio Corner) | 50.0Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-3dB) | 70Hz (measured, Erin’s Audio Corner) | 77Hz (measured, Erin’s Audio Corner) |
| Dimensions | 38.1”H x 11.5”W x 14.2”D (967 x 293 x 361 mm) | 24.8”H x 15.6”W x 13.3”D |
| Impedance | 6 ohms nominal (3.0 ohms minimum, measured by Erin’s Audio Corner) | Approximately 4 ohms minimum (measured, Erin’s Audio Corner) |
| Sensitivity | 91.5dB (measured average, Erin’s Audio Corner) | 94.5dB/2.83V/1m (measured, Erin’s Audio Corner) |
| Drivers | 0.88 in. decoupled dome tweeter, twin 5.0 in. C3 Continuous Curved Cone woofers | 1” horn-loaded tweeter; 1.75” horn-loaded midrange; 12” woofer |
| Weight | 39.7 lbs (18.0 kg) each | 45 lbs (20.4 kg) each |
| Woofer Cabinet | ported, rear | ported, rear |
| Spinorama Preference Score | 3.80 | 2.27 |
| Spinorama Preference Score with Perfect Sub | 6.41 | 5.02 |
| DIY Kit | No | No |
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Prices on this page were last checked October 2, 2026 at 10:18 PM 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
Q Acoustics 5040: $2,472.98 per pair Amazon eBay
Pros: C3 (Continuous Curved Cone) driver profile technology provides smooth midrange integration, controlled cone breakup, and improved bass damping. High voltage sensitivity (91.5dB SPL at 2.83V/1m) allows loud listening with low-to-moderate amplifier wattage. Cabinet features Point-to-Point (P2P) internal bracing and Helmholtz Pressure Equalizer (HPE) tubes to suppress internal standing waves and panel vibrations. Measured bass extension of 70Hz (-3dB), with a measured sensitivity of 91.5dB.
Cons: Free-field frequency response exhibits a noticeable mid-bass scoop around 200Hz (~6dB lower than mean SPL), causing an F3 of 70Hz (F10 of 39Hz) in open space and requiring boundary placement (11-22 inches from front wall) to reinforce upper bass output. Measurements indicate an enclosure resonance near 300Hz visible in sound power data. Minimum impedance drops to 3.0 ohms, demanding a stable 4-ohm rated amplifier despite high sensitivity.
Full Q Acoustics 5040 review and specifications →
| Bass Extension (-10dB) | 39Hz (measured, Erin’s Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 70Hz (measured, Erin’s Audio Corner) |
| DIY Kit | No |
| Dimensions | 38.1”H x 11.5”W x 14.2”D (967 x 293 x 361 mm) |
| Drivers | 0.88 in. decoupled dome tweeter, twin 5.0 in. C3 Continuous Curved Cone woofers |
| Impedance | 6 ohms nominal (3.0 ohms minimum, measured by Erin’s Audio Corner) |
| Sensitivity | 91.5dB (measured average, Erin’s Audio Corner) |
| Spinorama Preference Score | 3.80 |
| Spinorama Preference Score with Perfect Sub | 6.41 |
| Weight | 39.7 lbs (18.0 kg) each |
| Woofer Cabinet | ported, rear |
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Klipsch Heresy IV: $3,198 per pair Amazon Crutchfield eBay
Pros: Very high 94.5dB/2.83V/1m sensitivity in Erin’s anechoic measurement (well below Klipsch’s 99dB in-room claim, but still excellent) and strong short-term output from a 12-inch woofer plus horn-loaded midrange and tweeter. The compact, furniture-grade Heritage cabinet is easier to place than most high-efficiency designs, and dynamics at moderate levels can sound lively. A stable four-ohm-capable amplifier can produce substantial SPL with relatively little voltage. Measured bass extension of 77Hz (-3dB), with a measured sensitivity of 94.5dB.
Cons: Erin measured a 77Hz F3 and response rolling away near 100Hz in-room, so a subwoofer is required for modern full-range reproduction. The impedance dips to about 4 ohms, reducing the practical amplifier advantage implied by its sensitivity. Pronounced directivity mismatch at the driver transitions, impedance/response resonances and elevated distortion spikes around the crossover remain audible concerns that EQ cannot fully solve. At 102dB Erin measured roughly 1.5dB midband compression; at 96dB distortion rises around crossover. Performance is difficult to justify at the price, and Erin explicitly did not recommend it.
Full Klipsch Heresy IV review and specifications →
| Bass Extension (-10dB) | 50.0Hz (measured, Erin’s Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 77Hz (measured, Erin’s Audio Corner) |
| DIY Kit | No |
| Dimensions | 24.8”H x 15.6”W x 13.3”D |
| Drivers | 1” horn-loaded tweeter; 1.75” horn-loaded midrange; 12” woofer |
| Impedance | Approximately 4 ohms minimum (measured, Erin’s Audio Corner) |
| Sensitivity | 94.5dB/2.83V/1m (measured, Erin’s Audio Corner) |
| Spinorama Preference Score | 2.27 |
| Spinorama Preference Score with Perfect Sub | 5.02 |
| Weight | 45 lbs (20.4 kg) each |
| Woofer Cabinet | ported, rear |
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