The Fulcrum Acoustic RX4 ranks #22 out of 32 total Compact 5 to 6.5-Inch PA Speakers for sound quality. See all PA & Live Sound rankings for every top pick.
Brand: Fulcrum Acoustic
Prices on this page were last checked October 5, 2026 at 10:21 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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#22 Fulcrum Acoustic RX4 Passive eBay
Pros: A 1.4kg coaxial speaker small enough to hide under balconies or in architectural details, with wide 100° conical coverage for short throw fills. Measured bass extension of 165Hz (-3dB).
Cons: Vendor measurements give weak preference scores of -0.17 standalone and 4.13 with an ideal subwoofer, with an uneven on-axis response (3.53dB average deviation). Bass stops near 165Hz (-3dB), so it needs a subwoofer for anything but speech. Low 85dB sensitivity and a 111dB peak limit output. It is sold through pro dealers with no published price.
How it compares: Just above it: Alcons Audio SR9. Just below it: Biamp Community IC6-1062.
| AES Input | No |
|---|---|
| Amplifier Power | Passive speaker; requires external amplification |
| Aux Input | No |
| Bass Extension (-10dB) | about 128.6Hz (measured, vendor Spinorama data) |
| Bass Extension (-3dB) | 165Hz (measured, vendor Spinorama data) |
| Bluetooth | No |
| Coaxial Input | No |
| Configuration | Passive 2-way coaxial PA speaker |
| Coverage | 100° x 100° |
| DSP | No (passive) |
| Dimensions | 5”H x 5.3”W x 5.2”D (127 x 135 x 132 mm) |
| Drivers | 4” coaxial driver |
| Guitar Input | No |
| HDMI Input | No |
| Maximum SPL | 111dB peak / 105dB continuous (manufacturer specified) |
| Microphone Input | No |
| Optical Input | No |
| RCA Input | No |
| Sensitivity | 85dB |
| Spinorama Preference Score | -0.17 |
| Spinorama Preference Score with Perfect Sub | 4.13 |
| TRS Input | No |
| USB Input | No |
| Weight | 3.1 lbs (1.4 kg) |
| XLR Input | No |
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