Short answer: the Polk Reserve R100 for useful bass in a small cabinet, the Dynaudio Special Forty for a friendlier load. The R100’s compact cabinet delivers unusually useful bass with well-controlled woofer breakup, but Erin measured only about 85dB sensitivity and an impedance that reaches 3.6 ohms, so it is neither efficient nor a benign AVR load. The Special Forty’s tone comes with a glaring 3-4kHz quality. They are $2,901 apart.
Buy the Dynaudio Special Forty when sound quality outweighs the price for you, and the Polk Reserve R100 when the price outweighs sound quality instead.
Want more options? Browse the full Passive Home rankings.
Specifications Side By Side
| Dynaudio Special Forty | Polk Reserve R100 | |
|---|---|---|
| Price | $3600 per pair | $699.00 per pair |
| Ranked | #88 of 134 in Large Size Bookshelf Speakers | #96 of 134 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 39Hz (measured, Erin’s Audio Corner) | 49Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-3dB) | 54Hz (measured, Erin’s Audio Corner) | 68Hz (measured, Erin’s Audio Corner) |
| Dimensions | 14.1”H x 7.7”W x 12.1”D (358.1 x 195.6 x 307.3 mm) | 12.8”H x 6.5”W x 10.2”D |
| Impedance | 6 ohms nominal (4.9 ohms minimum above 80Hz, measured, Erin’s Audio Corner) | 3.6 ohms minimum (measured, Erin’s Audio Corner) |
| Sensitivity | 83.5dB (measured, Erin’s Audio Corner; 86dB manufacturer specified) | 85dB/2.83V/1m (measured, Erin’s Audio Corner) |
| Drivers | 5.9” MSP (Magnesium Silicate Polymer) cone woofer, 1” Esotar soft dome tweeter | 1” Pinnacle ring-radiator tweeter; 5.25” Turbine Cone midwoofer |
| Weight | 17.9 lbs (8.1 kg) each | 12.1 lbs (5.5 kg) each |
| Woofer Cabinet | ported | ported, rear X-Port |
| Spinorama Preference Score | 4.73 | 5.46 |
| Spinorama Preference Score with Perfect Sub | 6.74 | 7.93 |
| DIY Kit | No | No |
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Prices on this page were last checked October 3, 2026 at 10:26 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
Dynaudio Special Forty: $3600 per pair Safe and Sound HQ eBay
Pros: Smooth, “buttery” overall tonal character consistent with Dynaudio’s house sound. Surprisingly precise, focused imaging despite wide horizontal radiation (about ±70°): atypical, since wide-radiating speakers usually sacrifice some image precision in reflective rooms. Strong output capability: reached 100-101dB average at 3.5 meters with no audible distortion or woofer distress, and compression testing at 102dB shows the cabinet holding up mechanically well at extreme output. Bass reaches a genuine 50Hz (potentially 40Hz) in most rooms from a rear-ported design. Distortion stays below 1% at 86dB and doesn’t cross 3% THD until about 50Hz even at 96dB. Extra weight and impact on snares and percussion around 700-800Hz that the reviewer found appealing on many tracks. Measured bass extension of 54Hz (-3dB), with a measured sensitivity of 83.5dB.
Cons: A glaring, sometimes sibilant quality around 3-4kHz was the most noticeable issue in listening, the one thing the reviewer would want notched out with EQ. Multiple enclosure resonances appear between 500Hz-1kHz across on-axis, listening window, early-reflections, and sound-power measurements, corroborated by independent third-party CSD data showing similar 500-800Hz cabinet resonances. A dip around 1.2kHz traces to a cone-edge-to-surround compliance mismatch in the driver itself (confirmed by testing the bare driver’s impedance): a known artifact common to many similarly-sized drivers across several manufacturers, contributing to elevated second-order distortion in that region. A somewhat laid-back, recessed 1-2kHz character (sometimes described as a “BBC dip”) gives an overall subdued quality that isn’t overtly problematic but shapes the tonal balance. Impedance drops below 3 ohms in the 100-200Hz region, requiring a genuinely 4-ohm-stable amplifier rather than an AVR. Rear port means it can’t be placed directly against a wall.
Full Dynaudio Special Forty review and specifications →
| Bass Extension (-10dB) | 39Hz (measured, Erin’s Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 54Hz (measured, Erin’s Audio Corner) |
| DIY Kit | No |
| Dimensions | 14.1”H x 7.7”W x 12.1”D (358.1 x 195.6 x 307.3 mm) |
| Drivers | 5.9” MSP (Magnesium Silicate Polymer) cone woofer, 1” Esotar soft dome tweeter |
| Impedance | 6 ohms nominal (4.9 ohms minimum above 80Hz, measured, Erin’s Audio Corner) |
| Sensitivity | 83.5dB (measured, Erin’s Audio Corner; 86dB manufacturer specified) |
| Spinorama Preference Score | 4.73 |
| Spinorama Preference Score with Perfect Sub | 6.74 |
| Weight | 17.9 lbs (8.1 kg) each |
| Woofer Cabinet | ported |
- Links
- Reviews, Comparisons and Sound Samples
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Polk Reserve R100: $699.00 per pair Amazon Polk Audio eBay
Pros: Compact cabinet, unusually useful bass for its size and well-controlled woofer breakup. Erin measured F3/F10 points of 68Hz/49Hz, and the X-Port vent avoids much of the chuffing and pipe resonance common to budget rear ports. The 5.25-inch Turbine Cone woofer and 1-inch Pinnacle ring-radiator tweeter produce good detail at moderate levels, while listening roughly 20° off-axis reduces part of the elevated top octave. Measured bass extension of 68Hz (-3dB), with a measured sensitivity of 85dB.
Cons: Erin measured only about 85dB sensitivity and the impedance reaches 3.6 ohms, so it is neither efficient nor an entirely benign AVR load. The treble runs roughly 3dB above the midrange and becomes aggressive above about 85dB SPL. A directivity discontinuity through the woofer/tweeter crossover means EQ cannot fully repair the power response, and a 400Hz impedance feature plus 500Hz-1kHz response irregularity suggests a cabinet or system resonance. Substantial low-frequency compression at higher playback levels limits clean dynamics.
Full Polk Reserve R100 review and specifications →
| Bass Extension (-10dB) | 49Hz (measured, Erin’s Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 68Hz (measured, Erin’s Audio Corner) |
| DIY Kit | No |
| Dimensions | 12.8”H x 6.5”W x 10.2”D |
| Drivers | 1” Pinnacle ring-radiator tweeter; 5.25” Turbine Cone midwoofer |
| Impedance | 3.6 ohms minimum (measured, Erin’s Audio Corner) |
| Sensitivity | 85dB/2.83V/1m (measured, Erin’s Audio Corner) |
| Spinorama Preference Score | 5.46 |
| Spinorama Preference Score with Perfect Sub | 7.93 |
| Weight | 12.1 lbs (5.5 kg) each |
| Woofer Cabinet | ported, rear X-Port |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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