Short answer: the HiVi Swans 3.1A Sehlin Sound Solutions mod for the higher ranking, the Polk Monitor XT20 for the lower price. The HiVi Swans 3.1A Sehlin Sound Solutions mod ranks #13 of 47 bookshelf speakers at $346.74. The Polk Monitor XT20 ranks #35 at $279, $67.74 cheaper.
On the HiVi Swans 3.1A Sehlin Sound Solutions mod side: CEA2034 spinorama shows a mostly smooth on-axis response for a DIY three-way kit. The tradeoff: Some directivity error appears around 2.1kHz on-axis.
The case for the Polk Monitor XT20: Two-way bookshelf design with a 1” tweeter and 6.5” woofer. The tradeoff: Notably bright treble, elevated roughly 1-5dB above the midrange depending on frequency - a characteristic shared across the whole Polk XT.
Buy the HiVi Swans 3.1A Sehlin Sound Solutions mod if the ranking matters more than the price. Buy the Polk Monitor XT20 if the price matters more than the ranking.
Specifications Side By Side
| HiVi Swans 3.1A Sehlin Sound Solutions mod | Polk Monitor XT20 | |
|---|---|---|
| Price | $346.74 for the kit (assembly required) | $279.00 |
| Ranked | #13 of 47 in Large Size Bookshelf Speakers | #35 of 47 in Large Size Bookshelf Speakers |
| Bass Extension (-10dB) | 38Hz | 50Hz |
| Bass Extension (-3dB) | 60Hz | 75Hz |
| Impedance | 4 ohms | 8 ohms |
| Drivers | 6.5" Kevlar woofer, 2" Dome midrange, 1" Soft Dome tweeter | 6.5" bilaminate paper cone woofer, 1" Terylene dome tweeter |
| Sensitivity | 87dB | 87dB |
| Woofer Cabinet | Rear ported | Ported |
| Weight | 13.7 lbs / 6.2 kg | 11.9 lbs / 5.4 kg each |
| Dimensions | - | 13"H x 7.5"W x 11"D (330.2 x 190.5 x 279.4 mm) |
The Two Speakers In Full
HiVi Swans 3.1A Sehlin Sound Solutions mod: $346.74 for the kit (assembly required) Amazon
Pros: CEA2034 spinorama shows a mostly smooth on-axis response for a DIY three-way kit. Horizontal beamwidth of about ±70 degrees is wide and consistent. Distortion stays under control down to 40Hz at 96dB SPL/1m, a strong result for a 6.5” woofer in this class.
Cons: Some directivity error appears around 2.1kHz on-axis. Predicted in-room response needs about 1-2dB of correction to fit an ideal target curve. Vertical directivity is just okay, so listening height matters more than with a coincident design. Minimum impedance dips to 3.8 ohms with several peaks, a moderately demanding load. Requires DIY assembly (kit only), with additional Sehlin-mod parts and labor beyond the base kit price.
| Bass Extension (-10dB) | 38Hz |
|---|---|
| Bass Extension (-3dB) | 60Hz |
| Drivers | 6.5" Kevlar woofer, 2" Dome midrange, 1" Soft Dome tweeter |
| Impedance | 4 ohms |
| Sensitivity | 87dB |
| Weight | 13.7 lbs / 6.2 kg |
| Woofer Cabinet | Rear ported |
- Reviews, Comparisons and Sound Samples
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- Links
Polk Monitor XT20: $279.00 Crutchfield Amazon
Pros: Two-way bookshelf design with a 1” tweeter and 6.5” woofer, part of Polk’s budget-friendly XT lineup (spanning roughly $200-700 across the series). Measures more linear and has fewer/smaller cabinet resonances than its smaller sibling, the XT15, making it - by the reviewer’s own assessment - probably the better of the two based on data alone. Reasonably good bass output for the price and size, with an F3 of 63Hz. Horizontal radiation of about ±50° gives a respectable, enjoyable soundstage width. Takes well to EQ correction - the early-reflections directivity trend is decently linear, meaning tonal adjustments can meaningfully improve the sound. Provides usable, respectable volume when paired with a subwoofer crossover, even though it isn’t intended to play extremely loud on its own.
Cons: Notably bright treble, elevated roughly 1-5dB above the midrange depending on frequency - a characteristic shared across the whole Polk XT lineup, requiring either EQ or toe-out to tame. Small resonances appear around 300Hz and 800Hz, with some of that energy leaking from the port area. Vertical listening window is narrow - best kept close to the tweeter axis, with only a couple of degrees of tolerance above or below before the sound changes. Still needs a subwoofer for real low-end extension despite the decent F3. Overall linearity isn’t state-of-the-art flat, and while the reviewer found it pleasant, some artificial brightness remains even after basic EQ correction in the crossover region.
| Bass Extension (-10dB) | 50Hz |
|---|---|
| Bass Extension (-3dB) | 75Hz |
| Dimensions | 13"H x 7.5"W x 11"D (330.2 x 190.5 x 279.4 mm) |
| Drivers | 6.5" bilaminate paper cone woofer, 1" Terylene dome tweeter |
| Impedance | 8 ohms |
| Sensitivity | 87dB |
| Weight | 11.9 lbs / 5.4 kg each |
| Woofer Cabinet | Ported |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Links
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Product prices and availability were last checked August 9, 2026 at 6:57 AM UTC 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.