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Eminence · Professional Series

Eminence DefiniMax 4018LF

Eminence DefiniMax 4018LF: 18″ subwoofer driver with 4″ voice coil, shorting ring and Qts 0.34 – Eminence uses it to build its Single and Double Bass Bin.

Availability not checked · Last checked: 2026-11-13

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Schematic cross-section: 18″ driver with ferrite motor Side section: on the left the motor with a large ferrite ring magnet, pole piece and top plate with the air gap. The voice coil sits in the gap on its former, held by the spider. To the right the cone opens out with its dust cap, with the surround at the edge of the basket. The drawing shows the construction, not the dimensions of a particular model.
Schematic cross-section of a driver with a ferrite motor. The drawing shows the construction, not the dimensions of this model; the manufacturer has a product photo.

General data

Link to section “General data”
Type
Subwoofer driver
Nominal size
18″
Nominal impedance
8 Ω Manufacturer
Minimum impedance
not available
Sensitivity
94.9 dB 1 W / 1 m (2.83 V an 8 Ω) Manufacturer
Frequency range
31 Hz – 200 Hz Manufacturer
Voice coil Ø
102 mm Manufacturer
Winding height
not available
Gap depth
9.5 mm Manufacturer
Flux density
not available
Magnet
ferrite (109 oz)
Weight
10.9 kg Manufacturer
Baffle cut-out Ø
421 mm Manufacturer
Overall diameter
457 mm Manufacturer
Mounting depth
207 mm Manufacturer
Displacement
6.6 L Manufacturer
Recommended enclosure volume
99.11 – 227 L Manufacturer

Eminence references sensitivity to 1 W at 1 m at the nominal impedance, i.e. 2.83 V into 8 Ω, averaged over the usable frequency range; measured in a 2 × 2 ft baffle. Recommended enclosure volume according to the manufacturer: vented 99.11–226.54 L, sealed not intended (“N/A”).

Undercut pole piece with aluminium shorting ring and venting around the pole circumference, die-cast basket, water-repellent treated paper cone. Eminence ticks subwoofer as well as bass reflex, horn and scoop enclosures as applications. An older datasheet from 2012 still stated 800 W, Fs 32 Hz and Xmax 7.9 mm; the newer sheet applies here.

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.

Bass reflex Sealed Calculated

The EBP is between 50 and 100 – by the rule of thumb, both a bass reflex and a sealed enclosure are possible. This is based on an EBP of 86.

Net volume
214 L
Tuning frequency
34.5 Hz
F3 (−3 dB)
32.9 Hz
F6 (−6 dB)
29.6 Hz
F10 (−10 dB)
26.2 Hz
Sensitivity (2.83 V / 1 m)
96.2 dB
Max. SPL at 32.9 Hz
113.3 dB
Max. SPL at 65.8 Hz
116.5 dB
Xmax limits below
23.8 Hz
Ports
1 × 200 mm
Port area for 17 m/s
214 cm²
Max. port velocity
11.6 m/s
Port length
22.2 cm
1020501002005001k60708090100110120130Frequency (Hz)Level (dB SPL)
  • at 100 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.

Open in the designer

Thiele-Small parameters

Link to section “Thiele-Small parameters”

Small-signal parameters as stated by the manufacturer. They change with temperature and level.

Fs
30 Hz
Re
6.1 Ω
Le
4.54 mH
Qts
0.34
Qes
0.35
Qms
11.95
Vas
254.7 L
BL
26.8 T·m
Mms
217 g
Cms
0.13 mm/N
Sd
1,188 cm²
Xmax
8.6 mm
Xdamage
15.9 mm
Vd
1.02 L
EBP
86 Hz
Efficiency η₀
not available

Plausibility check

Link to section “Plausibility check”

We recalculate dependent values from the datasheet. We flag deviations above 3 %.

Recalculated parameters
CheckFormula DatasheetCalculatedResult
Qts from Qes and Qms Qts = Qes · Qms / (Qes + Qms) 0.34 0.34 consistent
EBP from Fs and Qes EBP = Fs / Qes 86 85.714 consistent
Vd from Sd and Xmax Vd = Sd · Xmax 1.018 1.018 consistent

Power handling

Link to section “Power handling”
  • EIA1,200 W
  • Programme power2,400 W

According to the footnote, several samples exceeded the rating according to EIA-426A, freely suspended and without temperature control. How Eminence determines programme power is not stated in the sheet.

Build plans with this driver

Link to section “Build plans with this driver”

Sources

Link to section “Sources”
  1. Tier A · primary source

    Eminence DefiniMax 4018LF – Datasheet (PDF, 2 pages)

    Eminence Speaker LLC · February 2015 (Date from file metadata) · accessed on 13 November 2026

    Hosted on the file server of the Eminence web shop. There is currently no product page for the driver on eminence.com. An older sheet at www.eminence.com/pdf/Definimax_4018LF.pdf (archive copy 2012) gives different values, including 800 W and Fs 32 Hz; the newer sheet applies here.

  2. Tier A · primary source

    DefiniMax 4018LF Single Bass Bin (build plan PDF, Ver. 1.0)

    Eminence Speaker, LLC · 7 November 2022 (Date from file metadata) · accessed on 13 September 2026

    US units; suppliers with part numbers from a US retailer. The file URL contains a version parameter and may change with updates.

  3. Tier A · primary source

    DefiniMax 4018LF Double Bass Bin (build plan PDF, Ver. 1.0)

    Eminence Speaker, LLC · 7 November 2022 (Date from file metadata) · accessed on 13 September 2026

    US units; suppliers with part numbers from a US retailer. The file URL contains a version parameter and may change with updates.