Short answer: the PSI Audio A21-M. Both are rated 4.5/5 for sound quality (#27 and #32 of 118 powered bookshelf speakers), and the PSI Audio A21-M costs $7,770 against $8,199.98 for the ADAM Audio S3H, with sound quality a draw, the lower price decides it.
What the ADAM Audio S3H does well: A horizontal three-way S Series monitor: two 7” HexaCone woofers either side of a 4” dome/cone midrange and the S-ART folded-ribbon tweeter, driven by 1,350W. 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 two-way ADAM Audio S2V.
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 PSI Audio A21-M. Both are rated the same for sound quality, and it costs $429.98 less than the ADAM Audio S3H.
Worth knowing: the ADAM Audio S3H has not been measured yet. Its rating is estimated from related models, with a likely range of 4.2 to 4.8, so treat this verdict as provisional.
Looking for alternatives? See the complete Powered Home rankings.
Specifications Side By Side
| ADAM Audio S3H | PSI Audio A21-M | |
|---|---|---|
| Price | $8,199.98 per pair | $7,770 per pair |
| Ranked | #32 of 118 in Large Size Powered Bookshelf Speakers Estimated | #27 of 118 in Large Size Powered Bookshelf Speakers |
| Weight | 58.6 lbs (26.6 kg) | 28.2 lbs (12.8 kg) each |
| Dimensions | 11”H x 23”W x 15”D (280 x 585 x 380 mm) | 15.7”H x 9.8”W x 11.8”D (400 x 250 x 300 mm) |
| Drivers | 2x 7” HexaCone woofers, 4” DCH dome/cone midrange, S-ART folded-ribbon tweeter in HPS waveguide | 27mm handmade dome tweeter, 172mm cone woofer |
| Inputs | XLR analog, AES/EBU digital | XLR (balanced analog) |
| Amplifier Power | 1,350W total | 335W total (280W woofer, 55W tweeter, Class A/B) |
| Frequency Response | 30Hz - 50kHz (manufacturer specified) | 38Hz-23kHz -6dB |
| Maximum SPL | 126dB peak @ 1m (manufacturer specified) | 110dB short term, 121dB peak (manufacturer specified) |
| XLR Input | Yes | Yes |
| RCA Input | No | No |
| TRS Input | No | 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 | No | No |
| DSP | Yes (selectable voicings, 6-band parametric EQ, delay) | - |
| 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 |
| Spinorama Preference Score | - | 6.07 |
| Spinorama Preference Score with Perfect Sub | - | 7.72 |
Related Speaker Comparisons
How PSI Audio A21-M compares with other leading options:
- Kii Seven vs PSI Audio A21-M
- ADAM Audio S3V vs PSI Audio A21-M
- Yamaha HS8 vs PSI Audio A21-M
- PSI Audio A21-M vs Kali Audio LP-6 V2
- Devialet Phantom Ultimate 108dB 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.
As an eBay Partner, we may be compensated if you make a purchase.
The Two Speakers In Full
ADAM Audio S3H: $8,199.98 per pair Estimated B&H Photo Video eBay
Same family: the ADAM Audio S2V (smaller bookshelf, ranked higher, rated 4.6/5), the ADAM Audio S3V (smaller bookshelf, ranked higher, estimated 4.5/5), the ADAM Audio S5V (larger bookshelf, ranked lower, estimated 4.4/5) and the ADAM Audio S5H (larger bookshelf, ranked lower, estimated 4.4/5).
Pros: A horizontal three-way S Series monitor: two 7” HexaCone woofers either side of a 4” dome/cone midrange and the S-ART folded-ribbon tweeter, driven by 1,350W. ADAM specifies 30Hz to 50kHz and 126dB peak output, and the horizontal layout suits soffit mounting or sitting under a large screen. Like the ADAM Audio S2V it uses a handmade S-ART folded-ribbon tweeter in an HPS waveguide and DSP with selectable voicings, a 6-band parametric EQ and delay for fitting it to the room, with analog XLR and AES digital inputs.
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 two-way ADAM Audio S2V. Side-by-side woofers can narrow horizontal dispersion through the crossover region compared with a vertical design, and it is a large, heavy cabinet for big control rooms.
Full ADAM Audio S3H review and specifications →
| Released | 2017 (9 years ago) |
|---|---|
| AES Input | Yes |
| Amplifier Power | 1,350W total |
| Aux Input | No |
| Bluetooth | No |
| Coaxial Input | No |
| DSP | Yes (selectable voicings, 6-band parametric EQ, delay) |
| Dimensions | 11”H x 23”W x 15”D (280 x 585 x 380 mm) |
| Drivers | 2x 7” HexaCone woofers, 4” DCH dome/cone midrange, S-ART folded-ribbon tweeter in HPS waveguide |
| Frequency Response | 30Hz - 50kHz (manufacturer specified) |
| HDMI Input | No |
| Inputs | XLR analog, AES/EBU digital |
| Maximum SPL | 126dB peak @ 1m (manufacturer specified) |
| Optical Input | No |
| RCA Input | No |
| TRS Input | No |
| USB Input | No |
| Weight | 58.6 lbs (26.6 kg) |
| 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
- PSI Audio A21-M vs Kii Seven
- PSI Audio A21-M vs ADAM Audio S3V
- PSI Audio A21-M vs Yamaha HS8
- PSI Audio A21-M vs Kali Audio LP-6 V2
- PSI Audio A21-M vs Devialet Phantom Ultimate 108dB
- PSI Audio A21-M vs KEF LS LUXE
- PSI Audio A21-M vs Focal Solo6 ST6
- PSI Audio A21-M vs Meyer Sound Amie
- See all 9 comparisons