Short answer: the Ascend Sierra 1 v2 for better sound quality, the Definitive Technology ProMonitor 1000 for the lower price. The Ascend Sierra 1 v2 ranks #3 of 74 bookshelf speakers at $1000. The Definitive Technology ProMonitor 1000 ranks #66 at $249, $751 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 Definitive Technology ProMonitor 1000 offers: Bass distortion is well controlled per the measurements, and the slow bass rolloff means it can be pushed fairly hard for its size. Ships with a footer that keeps the small cabinet planted despite its light weight. Watch for: CEA2034 spinorama shows severely reduced bass energy between 40-120Hz, a directivity mismatch between the tweeter and woofer, and a severe resonance/interference issue around 14kHz. Distortion at 96dB SPL was so bad the reviewer limited testing to 86dB. Direct comparison to a $118/pair Pioneer SP-BS22-LR left the reviewer calling the $500/pair ProMonitor 1000 “a bad experiment that should be forgotten” and concluding “there is nothing Pro about it.”
Buy the Ascend Sierra 1 v2 if sound quality matters more than the price. Buy the Definitive Technology ProMonitor 1000 if the price matters more than sound quality.
If sound quality matters at all to you, skip the Definitive Technology ProMonitor 1000. It ranks near the bottom of the 74 bookshelf speakers, so look higher up the list instead.
Specifications Side By Side
| Ascend Sierra 1 v2 | Definitive Technology ProMonitor 1000 | |
|---|---|---|
| Price | $1000 | $249.00 |
| Ranked | #3 of 74 in Medium Size Bookshelf Speakers | #66 of 74 in Medium Size Bookshelf Speakers |
| Bass Extension (-10dB) | 39Hz (measured, Erin’s Audio Corner) | 80Hz (measured, Audio Science Review) |
| Bass Extension (-3dB) | 55Hz (measured, Erin’s Audio Corner) | 95Hz (measured, Audio Science Review) |
| Dimensions | 14.2"H x 7.5"W x 10.5"D (361.9 x 190.5 x 266.7 mm) | 10.88H x 6.25W x 6.5D in |
| Impedance | 8 ohms nominal, 7 ohms minimum (measured, Erin’s Audio Corner) | 8 ohms nominal |
| Sensitivity | 81.5dB (measured, Erin’s Audio Corner) | 86dB (2.83V/1m, measured, Audio Science Review - reviewer noted this vs. a manufacturer spec of 91dB) |
| 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" aluminum dome tweeter, 5.25" BDSS mid/woofer, 5.25" planar bass radiator |
| Weight | 18.5 lbs / 8.4 kg each | 7.3 lbs / 3.29 kg each |
| Woofer Cabinet | ported | passive radiator |
| Frequency Response | - | 47Hz - 30kHz (Manufacturer specified) |
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- Ascend Sierra 1 v2 vs Emotiva B1+
- Sony SS-CS5 M2 vs Ascend Sierra 1 v2
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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
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- 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
Definitive Technology ProMonitor 1000: $249.00 Amazon eBay
Pros: Bass distortion is well controlled per the measurements, and the slow bass rolloff means it can be pushed fairly hard for its size. Ships with a footer that keeps the small cabinet planted despite its light weight.
Cons: CEA2034 spinorama shows severely reduced bass energy between 40-120Hz, a directivity mismatch between the tweeter and woofer, and a severe resonance/interference issue around 14kHz. Distortion at 96dB SPL was so bad the reviewer limited testing to 86dB. Direct comparison to a $118/pair Pioneer SP-BS22-LR left the reviewer calling the $500/pair ProMonitor 1000 “a bad experiment that should be forgotten” and concluding “there is nothing Pro about it.”
Full Definitive Technology ProMonitor 1000 review and specifications →
| Bass Extension (-10dB) | 80Hz (measured, Audio Science Review) |
|---|---|
| Bass Extension (-3dB) | 95Hz (measured, Audio Science Review) |
| Dimensions | 10.88H x 6.25W x 6.5D in |
| Drivers | 1" aluminum dome tweeter, 5.25" BDSS mid/woofer, 5.25" planar bass radiator |
| Frequency Response | 47Hz - 30kHz (Manufacturer specified) |
| Impedance | 8 ohms nominal |
| Sensitivity | 86dB (2.83V/1m, measured, Audio Science Review - reviewer noted this vs. a manufacturer spec of 91dB) |
| Weight | 7.3 lbs / 3.29 kg each |
| Woofer Cabinet | passive radiator |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Definitive Technology ProMonitor 1000 vs Polk T15
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