Short answer: the KEF R3. It ranks #15 of 222 bookshelf speakers by sound quality, rated 4.5/5, at $1,544.56; the Arendal Sound 1723 Monitor S THX ranks #66, rated 4.1/5, and costs $2,200, which makes this an easy call rather than a real tradeoff.
The KEF R3 is the more accurate, deeper-bass option. A three way bookshelf speaker with KEF’s coaxial driver for stable imaging across seats and very low distortion, easy to run with a modest amp. Its measured preference score, a predictor of how neutral it sounds, is 6.20 against 5.07 for the Arendal Sound 1723 Monitor S THX. Its bass reaches about 58Hz before falling 3dB, against 76.9Hz for the Arendal Sound 1723 Monitor S THX. Watch for: The low-frequency alignment rolls gradually rather than delivering high-output sub-bass; KEF specifies 58Hz +/-3dB and Erin’s high-level data supports using an 80Hz subwoofer crossover.
The case for the Arendal Sound 1723 Monitor S THX: A THX certified bookshelf speaker with twin woofers, smooth sound, healthy sensitivity, and port plugs to tune the bass to your room. The tradeoff: In the configuration measured, the bass response starts to fall early, about 77Hz at -3dB, though it keeps going to about 50Hz at -6dB and 33Hz at -10dB, so it benefits from a subwoofer or placement near a wall.
Buy the KEF R3. It is rated higher for sound quality than the Arendal Sound 1723 Monitor S THX and costs less, so it is the default pick unless a specific strength of the other one matters more to you.
Want more options? Browse the full Passive Home rankings.
Measured Differences
- Efficiency: the Arendal Sound 1723 Monitor S THX is rated at 88.7 dB sensitivity against 86 dB for the KEF R3, so it plays as loud with roughly two thirds of the amplifier power.
- Close enough not to matter: bass extension (35.2 Hz vs 32.9 Hz, 10 dB down).
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Specifications Side By Side
| KEF R3 | Arendal Sound 1723 Monitor S THX | |
|---|---|---|
| Price | $1,544.56 per pair | $2,200 per pair |
| Ranked | #15 of 222 in Large Size Bookshelf Speakers | #66 of 222 in Large Size Bookshelf Speakers |
| Bass Extension (-3dB) | Approximately 58Hz (manufacturer specified; consistent with Erin’s measured roll-off) | 76.9Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-10dB) | 35.2Hz (measured, Audio Science Review) | 32.9Hz (measured, Erin’s Audio Corner) |
| Sensitivity | Approximately 86-87dB/2.83V/1m (measured, Erin’s Audio Corner) | 88.7dB (manufacturer specified, 2.83V/1m) |
| Impedance | 8 ohms nominal; suitable for Erin’s 4/8-ohm-rated amplifier | 4 ohms nominal |
| Drivers | 1” tweeter coaxial with 5” midrange; 6.5” woofer | Two 6.5-inch woofers; 28mm waveguided tweeter |
| Dimensions | 16.6”H x 7.9”W x 13.2”D | 22.4”H x 9.6”W x 12.6”D (569 x 245 x 320 mm) |
| Woofer Cabinet | ported, rear Flexible Port | sealed or ported (port plugs included) |
| Weight | 29.9 lbs (13.55 kg) each | 41.2 lbs (18.7 kg) each |
| Spinorama Preference Score | 6.2 (spinorama.org) | 5.07 |
| Spinorama Preference Score with Perfect Sub | 7.97 (spinorama.org) | 7.08 |
| DIY Kit | No | No |
| Certification | - | THX Ultra |
| Frequency Response | - | 46Hz-20kHz ±3dB with two vents, 66Hz sealed (manufacturer specified) |
Where the Ratings Come From
- KEF R3: Spinorama.org measurements and reviews by Erin’s Audio Corner and Audio Science Review.
- Arendal Sound 1723 Monitor S THX: Spinorama.org measurements and reviews by Erin’s Audio Corner.
This comparison is generated from the ratings, specifications and measurements on each product’s own page, and it updates when that data changes. How we rank explains how each rating is decided.
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