RCF LF18N401
18″ neodymium woofer from RCF with 4″ voice coil – Thiele-Small parameters and power handling from the official product page.
Availability not checked · Last checked: 2026-09-13
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General data
Link to section “General data”- Type
- Subwoofer driver
- Nominal size
- 18″
- Nominal impedance
- 8 Ω Manufacturer
- Minimum impedance
- 6.3 Ω Manufacturer
- Sensitivity
- 98 dB Manufacturer
- Frequency range
- 30 Hz – 1,000 Hz Manufacturer
- Voice coil Ø
- 102 mm Manufacturer
- Winding height
- 25 mm Manufacturer
- Gap depth
- 15 mm Manufacturer
- Flux density
- not available
- Magnet
- neodymium
- Weight
- 9.5 kg Manufacturer
- Baffle cut-out Ø
- 424 mm Manufacturer
- Overall diameter
- 465 mm Manufacturer
- Mounting depth
- 204 mm RCF gives the mounting depth as the “Height” of the driver. Manufacturer
- Displacement
- 5.5 L Manufacturer
- Recommended enclosure volume
- not available
According to the product page “Max. Excursion Before Damage 52 mm” (whether peak-to-peak is not stated). We have taken the gap depth from the stated top plate thickness.
What can this driver do?
Link to section “What can this driver do?”Simulation from the datasheet values above. The suggestions are calculated, not stated by the manufacturer.
The EBP is above 100 – by the rule of thumb, this points to a vented enclosure (bass reflex). This is based on an EBP of 118.5.
- Net volume
- 115 L
- Tuning frequency
- 49 Hz
- F3 (−3 dB)
- 47.6 Hz
- F6 (−6 dB)
- 42.9 Hz
- F10 (−10 dB)
- 37.9 Hz
- Sensitivity (2.83 V / 1 m)
- 99 dB
- Max. SPL at 47.6 Hz
- 126.8 dB
- Max. SPL at 95.2 Hz
- 130.1 dB
- Xmax limits below
- 84.9 Hz
- Ports
- 3 × 150 mm
- Port area for 17 m/s
- 673 cm²
- Max. port velocity
- 21.6 m/s
- Port length
- 46.4 cm
- at 1,200 W
- Maximum SPL (limited by Xmax)
- Power into 8 Ω (nominal impedance of the wiring).
- Flattest alignment: lowest F3 without the response rising more than 0.25 dB above the passband level or dropping more than 0.5 dB at 2 × F3.
- The 17 m/s limit (about 5 % of the speed of sound) is a common rule of thumb against port noise, not a standard. Rounded port ends allow higher values.
- Lumped-element Thiele/Small model, Half space, 1 m, chamber losses QL 7, Le as a plain inductance, no room influence. At high levels (heating, non-linear Bl and Cms) real results are lower.
Thiele-Small parameters
Link to section “Thiele-Small parameters”Small-signal parameters as stated by the manufacturer. They change with temperature and level.
Plausibility check
Link to section “Plausibility check”We recalculate dependent values from the datasheet. We flag deviations above 3 %.
| Check | Formula | Datasheet | Calculated | Result |
|---|---|---|---|---|
| Qts from Qes and Qms | Qts = Qes · Qms / (Qes + Qms) | 0.26 | 0.259 | consistent |
| Xmax, geometric | Xmax = (winding height − gap depth) / 2 | 9 | 5 | different definition |
Manufacturers define Xmax differently. A deviation from the purely geometric formula is not an error, but shows that a different definition was used.
Power handling
Link to section “Power handling”- Continuous power (standard not stated)1,200 W
- Programme power2,400 W
Sources
Link to section “Sources”-
Tier A · primary source
LF18N401 Woofer – Product page with specifications
RCF · accessed on 13 September 2026