Short answer: the Ascend Sierra 1 v2 for better sound quality, the Polk Audio XT15 for the lower price. The Ascend Sierra 1 v2 ranks #3 of 74 bookshelf speakers at $1000. The Polk Audio XT15 ranks #28 at $179, $821 cheaper.
What the Ascend Sierra 1 v2 offers: Formaldehyde-free layered bamboo ply cabinet with a 1” dome tweeter over a 5.25” midwoofer, mated by a 4th-order acoustic crossover rather than a stock textbook design. In-room response is extremely linear - the reviewer called it “textbook” - a clear step up from the earlier V1, which had boxiness around 700Hz-1kHz and sibilance around 4-6kHz. Preference score of 8.4 with a subwoofer (6.8 without), which the reviewer calls topnotch. Wide, even horizontal radiation of about ±70° up to 6kHz. Better vertical directivity than its tweeter-to-woofer spacing would suggest, thanks to the steep 4th-order crossover slopes. No mechanical noise, port chuffing, or woofer bottoming even driven to 96dB/1m. In a three-way comparison against the Dynaudio Emit 20 and a Revel bookshelf model (all around $1,000/pair), measured as the most linear of the three and was the reviewer’s personal pick over both, despite the Dynaudio’s deeper bass and higher output capability. Independent ASR Klippel measurements corroborate Erin’s findings: superb off-axis response with only slight on-axis variations, and an in-room response the reviewer called “incredibly smooth and accurate - amazing for a non-DSP speaker.” Distortion above 200Hz at 86dB/1m is very low for the class. Watch for: F3 of 55Hz and F10 of 39Hz mean in-room extension tops out in the mid-40s Hz; the reviewer still recommends a subwoofer for full-range material. Diffraction dips appear around 3kHz and 5-6kHz, and the 1” dome tweeter starts beaming above roughly 6.7kHz, narrowing the soundstage radiation in the top octave - a straightforward consequence of dome size rather than a design flaw. At 96dB/1m the 5.25” midwoofer shows increased distortion in the midrange, likely tied to motor topology; high-passing to a subwoofer around 80Hz largely clears it up. Moderate sensitivity (~81-82dB average) with a 7-ohm minimum impedance. ASR’s power-sweep testing found response holds steady up to 96dB SPL/1m, but pushing to 102dB causes midbass below 400Hz to sag with distortion “through the roof” - a harder output ceiling than the 96dB tests alone suggest. Vertical directivity also narrows above about 1kHz, so the reviewer recommends staying at tweeter-axis height for best results.
What the Polk Audio XT15 offers: Very low $179/pair entry price for a Hi-Res Audio Certified 2-way design that’s Dolby Atmos and DTS:X compatible, and works with either 4- or 8-ohm amplifier outputs so it drops into almost any AVR without matching concerns. Directivity spread is reasonably even for the price (directivity_spdi_stddev 3.60). Watch for: Bass rolls off earlier than most of this batch at 77.6Hz (-3dB) / 54.2Hz (-10dB). On-axis deviation is the roughest measured figure here (aad_on_axis 0.449), and listening-window smoothness (0.303) trails the pricier options in this group. Modest 86dB sensitivity wants a reasonably powered amp channel. The 5.25” bi-laminate paper woofer is Polk’s entry-tier driver, not the polypropylene/Turbine cones used in its pricier Signature Elite/Reserve lines.
Buy the Ascend Sierra 1 v2 if sound quality matters more than the price. Buy the Polk Audio XT15 if the price matters more than sound quality.
Specifications Side By Side
| Ascend Sierra 1 v2 | Polk Audio XT15 | |
|---|---|---|
| Price | $1000 | $179.00 |
| Ranked | #3 of 74 in Medium Size Bookshelf Speakers | #28 of 74 in Medium Size Bookshelf Speakers |
| Bass Extension (-10dB) | 39Hz (measured, Erin’s Audio Corner) | 54.2Hz (measured, spinorama.org) |
| Bass Extension (-3dB) | 55Hz (measured, Erin’s Audio Corner) | 77.6Hz (measured, spinorama.org) |
| Dimensions | 14.2"H x 7.5"W x 10.5"D (361.9 x 190.5 x 266.7 mm) | 16.51 x 18.24cm (6.5 x 7.18 in), 4.08kg (9 lb) each |
| Impedance | 8 ohms nominal, 7 ohms minimum (measured, Erin’s Audio Corner) | 4/8-ohm compatible |
| Sensitivity | 81.5dB (measured, Erin’s Audio Corner) | 86dB (1W/1m) |
| Drivers | 5.25" proprietary mineral-filled polypropylene cone with cast aluminum frame woofer, 26mm aluminum/magnesium alloy dome tweeter with titanium former (SEAS Titan) | 1" Terylene dome tweeter, 5.25" bi-laminate paper woofer |
| Weight | 18.5 lbs / 8.4 kg each | 9 lbs / 4.08 kg (9 lb) each |
| Woofer Cabinet | ported | Ported |
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The Two Speakers In Full
Ascend Sierra 1 v2: $1000 Ascendacoustics eBay
Pros: Formaldehyde-free layered bamboo ply cabinet with a 1” dome tweeter over a 5.25” midwoofer, mated by a 4th-order acoustic crossover rather than a stock textbook design. In-room response is extremely linear - the reviewer called it “textbook” - a clear step up from the earlier V1, which had boxiness around 700Hz-1kHz and sibilance around 4-6kHz. Preference score of 8.4 with a subwoofer (6.8 without), which the reviewer calls topnotch. Wide, even horizontal radiation of about ±70° up to 6kHz. Better vertical directivity than its tweeter-to-woofer spacing would suggest, thanks to the steep 4th-order crossover slopes. No mechanical noise, port chuffing, or woofer bottoming even driven to 96dB/1m. In a three-way comparison against the Dynaudio Emit 20 and a Revel bookshelf model (all around $1,000/pair), measured as the most linear of the three and was the reviewer’s personal pick over both, despite the Dynaudio’s deeper bass and higher output capability. Independent ASR Klippel measurements corroborate Erin’s findings: superb off-axis response with only slight on-axis variations, and an in-room response the reviewer called “incredibly smooth and accurate - amazing for a non-DSP speaker.” Distortion above 200Hz at 86dB/1m is very low for the class.
Cons: F3 of 55Hz and F10 of 39Hz mean in-room extension tops out in the mid-40s Hz; the reviewer still recommends a subwoofer for full-range material. Diffraction dips appear around 3kHz and 5-6kHz, and the 1” dome tweeter starts beaming above roughly 6.7kHz, narrowing the soundstage radiation in the top octave - a straightforward consequence of dome size rather than a design flaw. At 96dB/1m the 5.25” midwoofer shows increased distortion in the midrange, likely tied to motor topology; high-passing to a subwoofer around 80Hz largely clears it up. Moderate sensitivity (~81-82dB average) with a 7-ohm minimum impedance. ASR’s power-sweep testing found response holds steady up to 96dB SPL/1m, but pushing to 102dB causes midbass below 400Hz to sag with distortion “through the roof” - a harder output ceiling than the 96dB tests alone suggest. Vertical directivity also narrows above about 1kHz, so the reviewer recommends staying at tweeter-axis height for best results.
Full Ascend Sierra 1 v2 review and specifications →
| Bass Extension (-10dB) | 39Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 55Hz (measured, Erin's Audio Corner) |
| Dimensions | 14.2"H x 7.5"W x 10.5"D (361.9 x 190.5 x 266.7 mm) |
| Drivers | 5.25" proprietary mineral-filled polypropylene cone with cast aluminum frame woofer, 26mm aluminum/magnesium alloy dome tweeter with titanium former (SEAS Titan) |
| Impedance | 8 ohms nominal, 7 ohms minimum (measured, Erin's Audio Corner) |
| Sensitivity | 81.5dB (measured, Erin's Audio Corner) |
| Weight | 18.5 lbs / 8.4 kg each |
| Woofer Cabinet | ported |
- Links
- Reviews, Comparisons and Sound Samples
- Erin’s Audio Corner: NEW! Ascend Acoustics Sierra-1 V2 Review More from Erin’s Audio Corner →
- Erin’s Audio Corner Website Ascend Sierra 1 v2
- Audio Science Review Ascend Sierra 1 v2 More from Audio Science Review →
- Erin’s Audio Corner: 5 AWESOME SPEAKERS Under $1000 You Won’t Regret
- Erin’s Audio Corner: I Tested 250 Speakers So You Don’t Have To!
- Erin’s Audio Corner: My Top Picks of 2023: Must-Haves Under $3000
- Manufacturer Measurements (spinorama.org)
- Reddit Search for Ascend Sierra 1 v2 Review
- Head-to-Head Comparisons
- Ascend Sierra 1 v2 vs KEF LS50 Meta
- Ascend Sierra 1 v2 vs Philharmonic Ceramic Mini
- Ascend Sierra 1 v2 vs Audio First Fidelia
- Ascend Sierra 1 v2 vs Arendal 1961 Monitor
- Ascend Sierra 1 v2 vs Moondrop M4P MTM
- Ascend Sierra 1 v2 vs Emotiva B1+
- Ascend Sierra 1 v2 vs Klipsch RP-500M II
- Ascend Sierra 1 v2 vs Wharfedale Super Denton
- See all 36 comparisons
Polk Audio XT15: $179.00 Amazon Bhphotovideo Crutchfield eBay
Pros: Very low $179/pair entry price for a Hi-Res Audio Certified 2-way design that’s Dolby Atmos and DTS:X compatible, and works with either 4- or 8-ohm amplifier outputs so it drops into almost any AVR without matching concerns. Directivity spread is reasonably even for the price (directivity_spdi_stddev 3.60).
Cons: Bass rolls off earlier than most of this batch at 77.6Hz (-3dB) / 54.2Hz (-10dB). On-axis deviation is the roughest measured figure here (aad_on_axis 0.449), and listening-window smoothness (0.303) trails the pricier options in this group. Modest 86dB sensitivity wants a reasonably powered amp channel. The 5.25” bi-laminate paper woofer is Polk’s entry-tier driver, not the polypropylene/Turbine cones used in its pricier Signature Elite/Reserve lines.
Full Polk Audio XT15 review and specifications →
| Bass Extension (-10dB) | 54.2Hz (measured, spinorama.org) |
|---|---|
| Bass Extension (-3dB) | 77.6Hz (measured, spinorama.org) |
| Dimensions | 16.51 x 18.24cm (6.5 x 7.18 in), 4.08kg (9 lb) each |
| Drivers | 1" Terylene dome tweeter, 5.25" bi-laminate paper woofer |
| Impedance | 4/8-ohm compatible |
| Sensitivity | 86dB (1W/1m) |
| Weight | 9 lbs / 4.08 kg (9 lb) each |
| Woofer Cabinet | Ported |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Polk Audio XT15 vs Wharfedale Diamond 220
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- Polk Audio XT15 vs JBL Studio 530
- Polk Audio XT15 vs Wharfedale Super Denton
- Polk Audio XT15 vs Klipsch RP-500M II
- Polk Audio XT15 vs ELAC Debut 2.0 B5.2
- See all 26 comparisons