Short answer: the Kii Seven. It ranks #23 of 118 powered bookshelf speakers by sound quality, rated 4.6/5, at $7,790. The PSI Audio A21-M ranks #27, rated 4.5/5, at $7,770, $20 cheaper, which does not close the gap in sound quality.
Why pick the Kii Seven: A smaller sibling of the Kii THREE that uses the same active wave focusing idea: side and rear woofers are driven by DSP to cancel sound going backward, giving a cardioid pattern so nearby walls color the bass far less than with a conventional box. Watch for: No independent measurements yet, so its tonal balance and directivity can’t be compared directly with measured speakers; the rating is estimated from the measured Kii THREE, which shares its cardioid design.
What the PSI Audio A21-M does well: ASR measured 39.6Hz -3dB extension and a 2.2dB response span from 300Hz to 5kHz, giving useful bass and broadly even mids. Watch for: The measured tonal result is good rather than a clear advance over less costly competitors.
Buy the Kii Seven. It is rated higher for sound quality, and the $20 you would save on the PSI Audio A21-M does not close the gap.
Worth knowing: the Kii Seven has not been measured yet. Its rating is estimated from related models, with a likely range of 4.3 to 4.9, so treat this verdict as provisional.
Looking for alternatives? See the complete Powered Home rankings.
Specifications Side By Side
| Kii Seven | PSI Audio A21-M | |
|---|---|---|
| Price | $7,790 per pair | $7,770 per pair |
| Ranked | #23 of 118 in Large Size Powered Bookshelf Speakers Estimated | #27 of 118 in Large Size Powered Bookshelf Speakers |
| XLR Input | Yes | Yes |
| RCA Input | No | No |
| TRS Input | Yes | No |
| Optical Input | No | No |
| Coaxial Input | No | No |
| USB Input | No | No |
| HDMI Input | No | No |
| AES Input | Yes | No |
| Aux Input | No | No |
| Bluetooth | Yes | No |
| Inputs | Analog XLR, TRS, AES/EBU digital, Wi-Fi, Bluetooth, Dante | XLR (balanced analog) |
| Drivers | 2x 6.5” woofers, 5” midrange, 1” waveguided tweeter | 27mm handmade dome tweeter, 172mm cone woofer |
| Amplifier Power | 600W per speaker | 335W total (280W woofer, 55W tweeter, Class A/B) |
| Frequency Response | 40Hz (-3dB); ±0.5dB 100Hz - 10kHz (manufacturer specified) | 38Hz-23kHz -6dB |
| Dimensions | 12.2” (310 mm) H x 203mm W x 310mm D | 15.7”H x 9.8”W x 11.8”D (400 x 250 x 300 mm) |
| Weight | 30.9 lbs (14 kg) each | 28.2 lbs (12.8 kg) each |
| DSP | Yes (cardioid active wave focusing, room and boundary EQ) | - |
| Wi-Fi | Yes | - |
| Enclosure | - | ported |
| Bass Extension (-3dB) | - | 39.6Hz (measured, Audio Science Review) |
| Bass Extension (-10dB) | - | 33.2Hz (measured, Audio Science Review) |
| Crossover Frequency | - | 2.4kHz |
| Warranty | - | 5+1 years |
| Country | - | Switzerland |
| Maximum SPL | - | 110dB short term, 121dB peak (manufacturer specified) |
| Spinorama Preference Score | - | 6.07 |
| Spinorama Preference Score with Perfect Sub | - | 7.72 |
Related Speaker Comparisons
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- Buchardt A10 vs Kii Seven
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- Devialet Phantom Ultimate 108dB vs PSI Audio A21-M
- ADAM Audio S3H vs PSI Audio A21-M
Prices on this page were last checked October 11, 2026 at 4:59 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
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The Two Speakers In Full
Kii Seven: $7,790 per pair Estimated Vintage King eBay
Same family: the Kii THREE (larger bookshelf, ranked higher, rated 4.9/5).
Pros: A smaller sibling of the Kii THREE that uses the same active wave focusing idea: side and rear woofers are driven by DSP to cancel sound going backward, giving a cardioid pattern so nearby walls color the bass far less than with a conventional box. Two 6.5” woofers, a 5” midrange and a waveguided 1” tweeter get 600W of amplification per speaker, and Kii specifies ±0.5dB from 100Hz to 10kHz with bass to 40Hz (-3dB). It accepts analog XLR, TRS and AES digital, and adds Wi-Fi streaming, Bluetooth and Dante, so it works as a studio monitor or a complete wireless hi-fi system.
Cons: No independent measurements yet, so its tonal balance and directivity can’t be compared directly with measured speakers; the rating is estimated from the measured Kii THREE, which shares its cardioid design. Bass extension stops around 40Hz, short of the larger Kii THREE, and the optional Kii Control remote costs extra.
Full Kii Seven review and specifications →
| Released | 2024 (2 years ago) |
|---|---|
| AES Input | Yes |
| Amplifier Power | 600W per speaker |
| Aux Input | No |
| Bluetooth | Yes |
| Coaxial Input | No |
| DSP | Yes (cardioid active wave focusing, room and boundary EQ) |
| Dimensions | 12.2” (310 mm) H x 203mm W x 310mm D |
| Drivers | 2x 6.5” woofers, 5” midrange, 1” waveguided tweeter |
| Frequency Response | 40Hz (-3dB); ±0.5dB 100Hz - 10kHz (manufacturer specified) |
| HDMI Input | No |
| Inputs | Analog XLR, TRS, AES/EBU digital, Wi-Fi, Bluetooth, Dante |
| Optical Input | No |
| RCA Input | No |
| TRS Input | Yes |
| USB Input | No |
| Weight | 30.9 lbs (14 kg) each |
| Wi-Fi | Yes |
| XLR Input | Yes |
- Links
- Reviews, Comparisons and Sound Samples
- No independent measurement review is linked for this model; it is ranked from hands-on listening and comparison against similarly priced speakers.
- Head-to-Head Comparisons
PSI Audio A21-M: $7,770 per pair B&H Photo Video eBay
Pros: ASR measured 39.6Hz -3dB extension and a 2.2dB response span from 300Hz to 5kHz, giving useful bass and broadly even mids. Its 7.72 ideal-subwoofer score supports serious monitoring, with analog phase compensation offering an alternative to DSP-based systems. Measured bass extension of 39.6Hz (-3dB).
Cons: The measured tonal result is good rather than a clear advance over less costly competitors. There is no built-in automatic room-calibration system, so placement or external correction still matters. The premium construction and analog circuitry should not be mistaken for proof of better audible performance.
Full PSI Audio A21-M review and specifications →
| AES Input | No |
|---|---|
| Amplifier Power | 335W total (280W woofer, 55W tweeter, Class A/B) |
| Aux Input | No |
| Bass Extension (-10dB) | 33.2Hz (measured, Audio Science Review) |
| Bass Extension (-3dB) | 39.6Hz (measured, Audio Science Review) |
| Bluetooth | No |
| Coaxial Input | No |
| Country | Switzerland |
| Crossover Frequency | 2.4kHz |
| Dimensions | 15.7”H x 9.8”W x 11.8”D (400 x 250 x 300 mm) |
| Drivers | 27mm handmade dome tweeter, 172mm cone woofer |
| Enclosure | ported |
| Frequency Response | 38Hz-23kHz -6dB |
| HDMI Input | No |
| Inputs | XLR (balanced analog) |
| Maximum SPL | 110dB short term, 121dB peak (manufacturer specified) |
| Optical Input | No |
| RCA Input | No |
| Spinorama Preference Score | 6.07 |
| Spinorama Preference Score with Perfect Sub | 7.72 |
| TRS Input | No |
| USB Input | No |
| Warranty | 5+1 years |
| Weight | 28.2 lbs (12.8 kg) each |
| XLR Input | Yes |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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