Short answer: the Ascend Sierra 1 v2. It ranks #3 of 160 bookshelf speakers by sound quality (rated 4.7/5) at $1,000 and is still sold new; the ELAC BS U5 ranks #108 (rated 2.9/5) and is discontinued, so it is only an option used.
What the ELAC BS U5 does well: This slim three-way coaxial design (an Andrew Jones creation) shows a fairly even on-axis response up to 3kHz, with off-axis behavior notably smoother than the on-axis curve. Watch for: Distortion is very high right at both crossover points (around 270Hz (mid-range) and 2700Hz (tweeter)) at both 86dB and 96dB SPL/1m, exceeding 3% at the mid-range crossover.
The Ascend Sierra 1 v2 is the more accurate, deeper-bass pick. 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. Its measured preference score, a predictor of how neutral it sounds, is 6.65 against 4.71 for the ELAC BS U5. Its bass reaches about 55Hz before falling 3dB, against 63Hz for the ELAC BS U5. The tradeoff: 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.
Buy the Ascend Sierra 1 v2. It is rated higher for sound quality, and the ELAC BS U5 is discontinued, so it is only available used.
Still deciding? The full Passive Home rankings cover every ranked option.
Specifications Side By Side
| ELAC BS U5 | Ascend Sierra 1 v2 | |
|---|---|---|
| Price | $856 per pair Discontinued | $1000 per pair |
| Ranked | #108 of 160 in Medium Size Bookshelf Speakers | #3 of 160 in Medium Size Bookshelf Speakers |
| Bass Extension (-3dB) | 63Hz (measured, Audio Science Review) | 55Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-10dB) | 41Hz (derived, log-interpolated between spinorama.org -9dB/-12dB points) | 39Hz (measured, Erin’s Audio Corner) |
| Drivers | 1” tweeter + 5.25” woofer | 5.25” proprietary mineral-filled polypropylene cone with cast aluminum frame woofer, 26mm aluminum/magnesium alloy dome tweeter with titanium former (SEAS Titan) |
| Weight | 13.2 lbs (6 kg) | 18.5 lbs (8.4 kg) each |
| Sensitivity | 83dB (2.83V/1m, measured, Audio Science Review) | 81.5dB (measured, Erin’s Audio Corner) |
| Impedance | 4 ohms nominal (3.4 ohms minimum) | 8 ohms nominal, 7 ohms minimum (measured, Erin’s Audio Corner) |
| Dimensions | 13.4”H x 7”W x 11.5”D (339.1 x 178.0 x 293.1 mm) | 14.2”H x 7.5”W x 10.5”D (361.9 x 190.5 x 266.7 mm) |
| Woofer Cabinet | ported, rear | ported |
| Spinorama Preference Score | 4.71 (spinorama.org) | 6.65 |
| Spinorama Preference Score with Perfect Sub | 6.79 (spinorama.org) | 8.61 |
| DIY Kit | No | No |
Related Speaker Comparisons
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- Ascend Sierra 1 v2 vs Audio First Fidelia
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The Two Speakers In Full
ELAC BS U5: $856 per pair Discontinued eBay
Pros: This slim three-way coaxial design (an Andrew Jones creation) shows a fairly even on-axis response up to 3kHz, with off-axis behavior notably smoother than the on-axis curve. Predicted in-room response looks like it should give good tonality. Vertical directivity is better than average, a benefit of the coaxial layout. Measured bass extension of 63Hz (-3dB), with a measured sensitivity of 83dB.
Cons: Distortion is very high right at both crossover points (around 270Hz (mid-range) and 2700Hz (tweeter)) at both 86dB and 96dB SPL/1m, exceeding 3% at the mid-range crossover. Minimum impedance dips to 3.4 ohms with a possible resonance around 500Hz visible in the impedance/phase curve. Discontinued.
Full ELAC BS U5 review and specifications →
| Bass Extension (-10dB) | 41Hz (derived, log-interpolated between spinorama.org -9dB/-12dB points) |
|---|---|
| Bass Extension (-3dB) | 63Hz (measured, Audio Science Review) |
| DIY Kit | No |
| Dimensions | 13.4”H x 7”W x 11.5”D (339.1 x 178.0 x 293.1 mm) |
| Drivers | 1” tweeter + 5.25” woofer |
| Impedance | 4 ohms nominal (3.4 ohms minimum) |
| Sensitivity | 83dB (2.83V/1m, measured, Audio Science Review) |
| Spinorama Preference Score | 4.71 (spinorama.org) |
| Spinorama Preference Score with Perfect Sub | 6.79 (spinorama.org) |
| Weight | 13.2 lbs (6 kg) |
| Woofer Cabinet | ported, rear |
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Ascend Sierra 1 v2: $1000 per pair Ascend Acoustics eBay
Same family: the Ascend Acoustics Sierra-2EX V2 (larger bookshelf, rated 4.3/5), the Ascend Acoustics Sierra-LX (larger bookshelf, rated 4.3/5), the Ascend Acoustics Sierra Titan Tower (floorstanding, rated 4.4/5) and the Ascend Acoustics Sierra Horizon V2 (center, estimated 4.3/5).
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. Measured bass extension of 55Hz (-3dB), with a measured sensitivity of 81.5dB.
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) |
| DIY Kit | No |
| 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) |
| Spinorama Preference Score | 6.65 |
| Spinorama Preference Score with Perfect Sub | 8.61 |
| 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)
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