Short answer: the Genelec 8351B. It ranks #4 of 68 powered bookshelf speakers by sound quality, rated 4.8/5, at $9,150; the JBL M2 Master Reference Monitor ranks #35, rated 4.3/5, and costs $15,000, so there is not much of a tradeoff to weigh.
Why pick the JBL M2 Master Reference Monitor: A high-output specialist: Erin’s low-distortion and compression tests support considerable dynamic capability, beyond what a single preference score captures. The catch: Its 4.1dB response span from 300Hz to 5kHz and 6.58 ideal-subwoofer score do not support a top tonal-accuracy ranking.
Why pick the Genelec 8351B: The vertical ASR measurement scores 7.75 with an ideal subwoofer and reaches 35.2Hz at -3dB. Watch for: Bass distortion increases at higher playback levels, so a subwoofer remains useful for demanding material.
Buy the Genelec 8351B. It is rated higher for sound quality than the JBL M2 Master Reference Monitor and costs less, so only choose the other one for a particular feature it does better.
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Specifications Side By Side
| JBL M2 Master Reference Monitor | Genelec 8351B | |
|---|---|---|
| Price | $15,000 per pair | $9150 per pair |
| Ranked | #35 of 68 in Large Size Powered Bookshelf Speakers | #4 of 68 in Large Size Powered Bookshelf Speakers |
| Bass Extension (-3dB) | 34Hz (measured, Erin’s Audio Corner) | 33Hz (measured, Audio Science Review) |
| Bass Extension (-10dB) | 21.0Hz (measured, Erin’s Audio Corner) | 28Hz (measured, Audio Science Review) |
| Drivers | 15” 2216Nd woofer; D2 compression driver in Image Control Waveguide | 8.6” woofer, 5” coaxial with tweeter midrange, 0.75” (19mm) coaxial tweeter |
| Crossover Frequency | 800Hz active DSP | - |
| Weight | 130.1 lbs (59 kg) each | 31.1 lbs (14.1 kg) each |
| Maximum SPL | 123dB manufacturer specified | 113dB @ 1m (manufacturer specified) |
| Spinorama Preference Score | 5.74 | - |
| Spinorama Preference Score with Perfect Sub | 6.58 | - |
| Amplifier Power | External two-channel amplification and JBL DSP tuning required | 550w Per Speaker |
| Inputs | None (passive cabinet driven by a matched Crown amplifier via speaker-level connection) | XLR |
| XLR Input | No | 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 | No | No |
| Aux Input | No | No |
| Dimensions | 49.4”H x 20”W x 14”D (1256 x 508 x 355.6 mm) | 17”H x 11.3”W x 10.9”D (431.8 x 287 x 276.9 mm) |
| Bluetooth | No | No |
| Frequency Response | 20Hz - 40kHz (±3dB) (Manufacturer specified) | 32Hz - 40kHz (±1.5dB) (Manufacturer specified) |
| App | - | Yes (GLM) |
| DSP | - | Yes |
| EQ | - | Yes (via GLM software) |
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Prices on this page were last checked September 29, 2026 at 3:43 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
JBL M2 Master Reference Monitor: $15,000 per pair JBL Professional Dealer Locator eBay
Pros: A high-output specialist: Erin’s low-distortion and compression tests support considerable dynamic capability, beyond what a single preference score captures. Measured -3dB extension is 33.7Hz. The large woofer and waveguide are particularly useful for greater listening distances. Measured bass extension of 34Hz (-3dB).
Cons: Its 4.1dB response span from 300Hz to 5kHz and 6.58 ideal-subwoofer score do not support a top tonal-accuracy ranking. It requires the correct external amplification and DSP rather than a simple built-in amplifier. The very large cabinet, installation cost and possible amplifier fan noise make it impractical for most desks.
Full JBL M2 Master Reference Monitor review and specifications →
| AES Input | No |
|---|---|
| Amplifier Power | External two-channel amplification and JBL DSP tuning required |
| Aux Input | No |
| Bass Extension (-10dB) | 21.0Hz (measured, Erin’s Audio Corner) |
| Bass Extension (-3dB) | 34Hz (measured, Erin’s Audio Corner) |
| Bluetooth | No |
| Coaxial Input | No |
| Crossover Frequency | 800Hz active DSP |
| Dimensions | 49.4”H x 20”W x 14”D (1256 x 508 x 355.6 mm) |
| Drivers | 15” 2216Nd woofer; D2 compression driver in Image Control Waveguide |
| Frequency Response | 20Hz - 40kHz (±3dB) (Manufacturer specified) |
| HDMI Input | No |
| Inputs | None (passive cabinet driven by a matched Crown amplifier via speaker-level connection) |
| Maximum SPL | 123dB manufacturer specified |
| Optical Input | No |
| RCA Input | No |
| Spinorama Preference Score | 5.74 |
| Spinorama Preference Score with Perfect Sub | 6.58 |
| TRS Input | No |
| USB Input | No |
| Weight | 130.1 lbs (59 kg) each |
| XLR Input | No |
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Genelec 8351B: $9150 per pair B&H Photo Video eBay
Pros: The vertical ASR measurement scores 7.75 with an ideal subwoofer and reaches 35.2Hz at -3dB. Coaxial midrange and treble help maintain consistent sound as the listening angle changes. Low measured distortion at ordinary listening levels and GLM calibration make it a strong precision-monitoring choice. Measured bass extension of 33Hz (-3dB).
Cons: Bass distortion increases at higher playback levels, so a subwoofer remains useful for demanding material. Upper-treble distortion in the test also cautions against assuming unlimited output. Calibration hardware adds to an already expensive system, and the quoted result is for the measured vertical orientation.
Full Genelec 8351B review and specifications →
| AES Input | No |
|---|---|
| Amplifier Power | 550w Per Speaker |
| App | Yes (GLM) |
| Aux Input | No |
| Bass Extension (-10dB) | 28Hz (measured, Audio Science Review) |
| Bass Extension (-3dB) | 33Hz (measured, Audio Science Review) |
| Bluetooth | No |
| Coaxial Input | No |
| DSP | Yes |
| Dimensions | 17”H x 11.3”W x 10.9”D (431.8 x 287 x 276.9 mm) |
| Drivers | 8.6” woofer, 5” coaxial with tweeter midrange, 0.75” (19mm) coaxial tweeter |
| EQ | Yes (via GLM software) |
| Frequency Response | 32Hz - 40kHz (±1.5dB) (Manufacturer specified) |
| HDMI Input | No |
| Inputs | XLR |
| Maximum SPL | 113dB @ 1m (manufacturer specified) |
| Optical Input | No |
| RCA Input | No |
| TRS Input | No |
| USB Input | No |
| Weight | 31.1 lbs (14.1 kg) each |
| XLR Input | Yes |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
- Genelec 8351B vs Neumann KH420
- Genelec 8351B vs Genelec 8361A
- Genelec 8351B vs Neumann KH 150
- Genelec 8351B vs Aalto Speakers Aalto 3 Active Pro
- Genelec 8351B vs Neumann KH 310 A
- Genelec 8351B vs HEDD Type 20 MK2
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