Short answer: the Genelec 8351B. It ranks #4 of 66 powered bookshelf speakers by sound quality at $9150; the JBL M2 Master Reference Monitor ranks #34 and costs $15000, so there is not much of a tradeoff to weigh.
What the JBL M2 Master Reference Monitor offers: Flagship quasi-active two-way with a 15-inch 2216Nd woofer and D2 compression driver crossing near 800Hz through a large Image Control Waveguide. Watch for: The required bi-amplification/DSP ecosystem is expensive and complex; Erin’s Crown I-Tech 5000HD had fans loud enough that he moved it to another room for measurements.
What the Genelec 8351B offers: CEA2034 spinorama shows exceptionally flat response both on- and off-axis. Watch for: Deep bass distortion rises substantially at higher output (96dB SPL/1m) - the reviewer notes “deep bass suffers” below about 100Hz.
Buy the Genelec 8351B. It ranks higher for sound quality than the JBL M2 Master Reference Monitor and costs less, which settles it without a real tradeoff to make.
Specifications Side By Side
| JBL M2 Master Reference Monitor | Genelec 8351B | |
|---|---|---|
| Price | $15,000/pair | $9150 |
| Ranked | #34 of 66 in Large Size Powered Bookshelf Speakers | #4 of 66 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) |
| Sensitivity | Not applicable (externally bi-amplified DSP system) | - |
| 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 | 800Hz active DSP | - |
| Max SPL | 123dB manufacturer specified | 113dB @ 1m |
| Weight | 130 lb each | 31.1 lbs / 14.1 kg each |
| Amplification | External two-channel amplification and JBL DSP tuning required | - |
| Dimensions | - | 17"H x 11.3"W x 10.9"D (431.8 x 287 x 276.9 mm) |
| Inputs | - | XLR |
| App | - | Yes (GLM) |
| Bluetooth | - | No |
| DSP | - | Yes |
| EQ | - | Yes (via GLM software) |
| Frequency Response | - | 32Hz - 40kHz (±1.5dB) (Manufacturer specified) |
| Output Power | - | 550w Per Speaker |
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The Two Speakers In Full
JBL M2 Master Reference Monitor: $15,000/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.
Cons: Its 4.1dB response span from 300Hz to 5kHz and 5.67 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 →
| Amplification | External two-channel amplification and JBL DSP tuning required |
|---|---|
| Bass Extension (-10dB) | 21.0Hz (measured, Erin's Audio Corner) |
| Bass Extension (-3dB) | 34Hz (measured, Erin's Audio Corner) |
| Crossover | 800Hz active DSP |
| Drivers | 15" 2216Nd woofer; D2 compression driver in Image Control Waveguide |
| Max SPL | 123dB manufacturer specified |
| Sensitivity | Not applicable (externally bi-amplified DSP system) |
| Weight | 130 lb each |
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Genelec 8351B: $9150 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.
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 →
| App | Yes (GLM) |
|---|---|
| Bass Extension (-10dB) | 28Hz (measured, Audio Science Review) |
| Bass Extension (-3dB) | 33Hz (measured, Audio Science Review) |
| Bluetooth | 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) |
| Inputs | XLR |
| Max SPL | 113dB @ 1m |
| Output Power | 550w Per Speaker |
| Weight | 31.1 lbs / 14.1 kg each |
- Links
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons