Short answer: the KEF LS50 Meta. It ranks #4 of 87 bookshelf speakers by sound quality at $1599; the SunAudio Purified 4 ranks #9 and costs $3650, so there is not much of a tradeoff to weigh.
What the KEF LS50 Meta offers: Uni-Q concentric driver mounts a 1” vented aluminum dome tweeter at the center of a 5.25” aluminum cone woofer, rated 79Hz-20kHz+. Speaker-to-speaker matching measured tight at roughly 0.5dB deviation between the pair tested, versus 2-3dB seen on some other speakers - likely why imaging stayed so precise. Imaging stays tight and focused even toed out, unlike most coincident designs where toe-out typically diffuses the image, giving more of an oval-shaped soundstage than a hard rectangular boundary. Horizontal and vertical directivity both hold to about ±50° at the -6dB point, so tonality stays consistent across roughly a 100° listening cone. The extended bass shelf is deliberately tuned for near-wall/boundary placement rather than the usual “pull it 3 feet into the room” advice, playing lower without excess boominess when placed close to a wall. At $1,000 (a frequent sale price versus $1,600 list), called a no-brainer for a compact stand-mount speaker. Independent ASR Klippel measurements corroborate this: very good directivity with the on- and off-axis curves tracking closely, and a predicted in-room response the reviewer called “very close to ideal.” Watch for: F3 of 67Hz and F10 of 42Hz mean it doesn’t get much below 50Hz in-room; a subwoofer is recommended for real bass. A 2-3dB scoop around 2-4kHz shows up in both the listening window and sound power measurements, matching a subjectively noticed lack of attack and vocal clarity that the reviewer wanted to correct with about 2dB of EQ. An on-axis diffraction dip around 8kHz smooths out with about 15° of toe-out (typical for concentric designs, but still present at 0°). Distortion is elevated at low frequencies since the single 5.25” cone shares surface area with the tweeter housing, reducing effective radiating area; multitone distortion crosses the 3% threshold at 96dB/1m, making roughly 88dB or below the safer output ceiling. Moderate sensitivity (~83dB average) needed 2-3dB more amplifier gain than typical in testing. Adding a subwoofer at an 80Hz crossover only helps lower-midrange distortion, not the elevated distortion in the 1-2kHz and above-5kHz regions. ASR’s own Klippel testing found the same pattern in starker terms: THD is very good at 86dB SPL/1m but climbs past 100% in the bass at 96dB SPL/1m, confirming this is not a near-field speaker for high-output bass-heavy material. Cumulative spectral decay (waterfall) also shows a couple of resonances lingering in the 1-2kHz region.
What the SunAudio Purified 4 offers: On-axis response is essentially dead flat from 100Hz to 20kHz, staying within about ±1dB through most of the band and widening only to a gentle +1.5dB rise in the top octave. The listening window curve tracks on-axis almost exactly, meaning off-axis output stays consistent rather than diverging. Both directivity index curves rise smoothly and monotonically from the bass straight through to 20kHz with no bumps, dips, or discontinuities - a sign of very well-integrated driver-to-driver handoff from the beryllium-dome tweeter. Early reflections and sound power both decline smoothly with frequency, with no resonant peaks anywhere in the response. The manufacturer’s own preference-score modeling comes out to 6.65 unequalized (rising to 9.36 with an ideal subwoofer) with a frequency deviation of just 0.8dB across 300Hz-5kHz - genuinely flagship-tier numbers for a 4-inch woofer design. Distinctive modular build: separate CNC-machined aluminum enclosures for the Purifi 4” woofer and BlieSMa T25A beryllium-dome tweeter, mounted on their own tripod stand, with cone-material and finish options. Watch for: A 4-inch woofer means real bass extension is limited - -3dB around 71Hz and -10dB around 53Hz - so a subwoofer is needed for anything below the low-100s. Measured sensitivity of 84.4dB is on the low side, meaning it needs more amplifier power than more efficient designs to reach the same volume. This is manufacturer self-measured data with no independent third-party review, so there’s no outside verification of distortion, unit-to-unit consistency, or how the reference crossover performs outside SunAudio’s own lab. The modular two-sphere design and tripod stand is unconventional, and pricing is steep for such a small woofer given the niche, boutique nature of the brand.
Buy the KEF LS50 Meta. It ranks higher for sound quality than the SunAudio Purified 4 and costs less, so there is no real case for the other one.
Specifications Side By Side
| KEF LS50 Meta | SunAudio Purified 4 | |
|---|---|---|
| Price | $1,599.00 | $3,650 as tested (pair); modular kit, pricing varies by driver/finish configuration |
| Ranked | #4 of 87 in Medium Size Bookshelf Speakers | #9 of 87 in Medium Size Bookshelf Speakers |
| Bass Extension (-10dB) | 43Hz (measured, Erin’s Audio Corner) | 53Hz (measured, manufacturer spinorama data) |
| Bass Extension (-3dB) | 68Hz (measured, Erin’s Audio Corner) | 71Hz (measured, manufacturer spinorama data) |
| Dimensions | 11.9"H x 7.9"W x 11"D (302 x 200 x 280.5 mm) | - |
| Impedance | 8 ohms nominal (3.7 ohms minimum above 80Hz, measured by Erin’s Audio Corner) | 4 ohms |
| Sensitivity | 83dB (measured average, Erin’s Audio Corner; 85dB manufacturer specified) | 84.4dB (2.83V/1m, measured, manufacturer spinorama data) |
| Drivers | 130 mm (5.25 in.) aluminium cone woofer, 25 mm (1 in.) vented aluminium dome with Metamaterial Absorption tweeter | BlieSMa T25A beryllium-dome tweeter (own CNC aluminum enclosure), Purifi 4" Ultra Low Distortion Extended woofer (PP-coated paper/fiber cone) |
| Weight | 17.2 lbs / 7.8 kg each | - |
| Woofer Cabinet | ported, rear | sealed, separate spherical driver modules on tripod stand |
| Power Handling | - | 200W long-term max (woofer) |
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- Ascend Sierra 1 v2 vs Radiant Acoustics Clarity 4.2
- Arendal 1961 Monitor vs Revel M105
- SunAudio Purified 4 vs Arendal 1961 Monitor
- KEF LS50 Meta vs Radiant Acoustics Clarity 4.2
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The Two Speakers In Full
KEF LS50 Meta: $1,599.00 Amazon Crutchfield eBay
Pros: Uni-Q concentric driver mounts a 1” vented aluminum dome tweeter at the center of a 5.25” aluminum cone woofer, rated 79Hz-20kHz+. Speaker-to-speaker matching measured tight at roughly 0.5dB deviation between the pair tested, versus 2-3dB seen on some other speakers - likely why imaging stayed so precise. Imaging stays tight and focused even toed out, unlike most coincident designs where toe-out typically diffuses the image, giving more of an oval-shaped soundstage than a hard rectangular boundary. Horizontal and vertical directivity both hold to about ±50° at the -6dB point, so tonality stays consistent across roughly a 100° listening cone. The extended bass shelf is deliberately tuned for near-wall/boundary placement rather than the usual “pull it 3 feet into the room” advice, playing lower without excess boominess when placed close to a wall. At $1,000 (a frequent sale price versus $1,600 list), called a no-brainer for a compact stand-mount speaker. Independent ASR Klippel measurements corroborate this: very good directivity with the on- and off-axis curves tracking closely, and a predicted in-room response the reviewer called “very close to ideal.”
Cons: F3 of 67Hz and F10 of 42Hz mean it doesn’t get much below 50Hz in-room; a subwoofer is recommended for real bass. A 2-3dB scoop around 2-4kHz shows up in both the listening window and sound power measurements, matching a subjectively noticed lack of attack and vocal clarity that the reviewer wanted to correct with about 2dB of EQ. An on-axis diffraction dip around 8kHz smooths out with about 15° of toe-out (typical for concentric designs, but still present at 0°). Distortion is elevated at low frequencies since the single 5.25” cone shares surface area with the tweeter housing, reducing effective radiating area; multitone distortion crosses the 3% threshold at 96dB/1m, making roughly 88dB or below the safer output ceiling. Moderate sensitivity (~83dB average) needed 2-3dB more amplifier gain than typical in testing. Adding a subwoofer at an 80Hz crossover only helps lower-midrange distortion, not the elevated distortion in the 1-2kHz and above-5kHz regions. ASR’s own Klippel testing found the same pattern in starker terms: THD is very good at 86dB SPL/1m but climbs past 100% in the bass at 96dB SPL/1m, confirming this is not a near-field speaker for high-output bass-heavy material. Cumulative spectral decay (waterfall) also shows a couple of resonances lingering in the 1-2kHz region.
Full KEF LS50 Meta review and specifications →
| Bass Extension (-10dB) | 43Hz (measured, Erin's Audio Corner) |
|---|---|
| Bass Extension (-3dB) | 68Hz (measured, Erin's Audio Corner) |
| Dimensions | 11.9"H x 7.9"W x 11"D (302 x 200 x 280.5 mm) |
| Drivers | 130 mm (5.25 in.) aluminium cone woofer, 25 mm (1 in.) vented aluminium dome with Metamaterial Absorption tweeter |
| Impedance | 8 ohms nominal (3.7 ohms minimum above 80Hz, measured by Erin's Audio Corner) |
| Sensitivity | 83dB (measured average, Erin's Audio Corner; 85dB manufacturer specified) |
| Weight | 17.2 lbs / 7.8 kg each |
| Woofer Cabinet | ported, rear |
- Links
- Reviews, Comparisons and Sound Samples
- Erin’s Audio Corner: Unveiling the KEF LS50 Meta: The Truth Behind the Hype More from Erin’s Audio Corner →
- Erin’s Audio Corner Website KEF LS50 Meta
- Audio Science Review KEF LS50 Meta More from Audio Science Review →
- GR-Research: KEF LS50 Meta! Worthy of HYPE? More from GR-Research →
- Erin’s Audio Corner: My Top Picks of 2023: Must-Haves Under $3000
- Erin’s Audio Corner Measurements (spinorama.org)
- Reddit Search for KEF LS50 Meta Review
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- KEF LS50 Meta vs Arendal 1961 Monitor
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- See all 61 comparisons
SunAudio Purified 4: $3,650 as tested (pair); modular kit, pricing varies by driver/finish configuration SunAudio eBay
Pros: On-axis response is essentially dead flat from 100Hz to 20kHz, staying within about ±1dB through most of the band and widening only to a gentle +1.5dB rise in the top octave. The listening window curve tracks on-axis almost exactly, meaning off-axis output stays consistent rather than diverging. Both directivity index curves rise smoothly and monotonically from the bass straight through to 20kHz with no bumps, dips, or discontinuities - a sign of very well-integrated driver-to-driver handoff from the beryllium-dome tweeter. Early reflections and sound power both decline smoothly with frequency, with no resonant peaks anywhere in the response. The manufacturer’s own preference-score modeling comes out to 6.65 unequalized (rising to 9.36 with an ideal subwoofer) with a frequency deviation of just 0.8dB across 300Hz-5kHz - genuinely flagship-tier numbers for a 4-inch woofer design. Distinctive modular build: separate CNC-machined aluminum enclosures for the Purifi 4” woofer and BlieSMa T25A beryllium-dome tweeter, mounted on their own tripod stand, with cone-material and finish options.
Cons: A 4-inch woofer means real bass extension is limited - -3dB around 71Hz and -10dB around 53Hz - so a subwoofer is needed for anything below the low-100s. Measured sensitivity of 84.4dB is on the low side, meaning it needs more amplifier power than more efficient designs to reach the same volume. This is manufacturer self-measured data with no independent third-party review, so there’s no outside verification of distortion, unit-to-unit consistency, or how the reference crossover performs outside SunAudio’s own lab. The modular two-sphere design and tripod stand is unconventional, and pricing is steep for such a small woofer given the niche, boutique nature of the brand.
Full SunAudio Purified 4 review and specifications →
| Bass Extension (-10dB) | 53Hz (measured, manufacturer spinorama data) |
|---|---|
| Bass Extension (-3dB) | 71Hz (measured, manufacturer spinorama data) |
| Drivers | BlieSMa T25A beryllium-dome tweeter (own CNC aluminum enclosure), Purifi 4" Ultra Low Distortion Extended woofer (PP-coated paper/fiber cone) |
| Impedance | 4 ohms |
| Power Handling | 200W long-term max (woofer) |
| Sensitivity | 84.4dB (2.83V/1m, measured, manufacturer spinorama data) |
| Woofer Cabinet | sealed, separate spherical driver modules on tripod stand |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons