18SOUND 21LW1400
18SOUND (Eighteen Sound) 21LW1400 — 21" / 21 inch · Woofer · Subwoofer / Bass · Ferrite Magnet
4" voice coil · 8 Ω
Part no.: 42A-CHS-TT-18S-0002
Documents
18SOUND 21LW1400 — 21" · Woofer
1000 W AES · 99 dB Sensitivity · Frequency range 24 Hz – 2000 Hz
Technical data
- Diameter: 21 "
- Voice coil: 4 "
- Power handling: 1000 W AES
- Sensitivity: 99 dB
- Impedance: 8 Ω
- Magnet: Ferrite
- Weight: 17 kg
- Mounting depth: 259 mm
- Frequency range: 24 – 2000 Hz
Datasheet (PDF) · Manufacturer page
Series: LW · Part no.: 42A-CHS-TT-18S-0002
18Sound 21LW1400: 21" ferrite woofer with 99 dB and fs 28 Hz for reflex subwoofers
The 21LW1400 is the efficiency specialist among 18Sound's 21" drivers: 99 dB sensitivity, ferrite motor with 4" voice coil, 1000 W handling at 8 Ω. A resonance of 28 Hz with 0.296 kg of moving mass and Vas 385 l describes a large, softly suspended cone with a strong motor – BL 33.5 Tm at Re 5 Ω.
Qts 0.24 is low, so the motor dominates the damping. Drivers like this want bass reflex or horn loading; in sealed boxes little of the extension remains. Xmax is 9.5 mm: not a long-throw sub, but a driver that makes level through cone area (Sd 0.166 m²) and efficiency. The response runs from 24 to 2000 Hz, which also qualifies the 21LW1400 for low-crossed bass sections beyond pure subwoofer duty.
Use and enclosure
With an EBP of 117, bass reflex is the way to go. The guideline: about 96 l tuned to 42 Hz with f3 around 54 Hz. That is a compact volume for a 21" – if you want to go deeper, use the enclosure calculator at 42.audio to explore larger volumes and lower tuning, keeping an eye on excursion. Sealed would give about 50 l with fc at 82 Hz, practically usable only with heavy equalisation.
As a subwoofer it is crossed over low; with 9.5 mm Xmax a high-pass below the tuning frequency matters more than amplifier headroom. The 259 mm mounting depth and 17 kg weight belong in the cabinet plan, especially for dual-driver boxes.
What to look out for
- Qts 0.24, EBP 117: bass reflex or horn, not sealed
- Xmax 9.5 mm – plan for a limiter and a high-pass
- 99 dB sensitivity: 1000 W is enough for very high levels
- 17 kg of ferrite weight, mounting depth 259 mm
- 8 Ω, Re 5 Ω, Le 2.85 mH
Frequently asked questions
How does the 21LW1400 differ from the 21LW2600 in the same series?
The 21LW2600 sits at fs 27 Hz, Qts 0.29 and 332 l Vas, the 21LW1400 at fs 28 Hz, Qts 0.24 and 385 l. The 21LW1400 is the more motor-dominated, efficiency-oriented driver and absolutely needs reflex or horn loading.
Which amplifier suits it?
An amplifier around 1000 W at 8 Ω is sufficient; two drivers in parallel at 4 Ω are no problem for most PA amplifiers. A high-pass is essential, since 9.5 mm Xmax is reached quickly below the tuning frequency.
Is the 21LW1400 suitable for bandpass or horn cabinets?
Yes, the low Q and high efficiency are typical of horn-loaded bass drivers. Vas 385 l and fs 28 Hz, however, demand correspondingly large horn mouths or bandpass chambers.
18Sound 21LW1400: manufacturer, spellings and classification
18Sound, 18 Sound and Eighteensound all refer to the same manufacturer: Eighteen Sound S.r.l. of Reggio Emilia, Italy. The 21LW1400 is a 21-inch woofer with ferrite magnet from the LW series, available from 42.audio, 18Sound dealer in Germany, with datasheet and full specifications in the driver database.
At 42.audio you get the 18SOUND 21LW1400 with datasheet PDF, all key data in the driver database and the enclosure calculator. More drivers from this manufacturer: Atlas 18Sound.
Thiele-Small parameters
| Nominal impedance | 8 Ω |
|---|---|
| Resonance frequency fs | 28 Hz |
| Total Q Qts | 0.24 |
| Electrical Q Qes | 0.24 |
| Mechanical Q Qms | 9.32 |
| Equivalent volume Vas | 385.0 l |
| Moving mass Mms | 296.0 g |
| Cone area Sd | 1,660 cm² |
| Linear excursion Xmax | 9.5 mm |
| Force factor BL | 33.5 Tm |
| DC resistance Re | 5 Ω |
| Voice coil inductance Le | 2.85 mH |
Enclosure suggestion
The EBP of 117 suggests a bass-reflex enclosure. EBP = fs / Qes = 28 / 0.24
Sealed (Qtc 0.707)
- Enclosure volume Vb
- 50.1 l
- System resonance Fc
- 82 Hz
- Cut-off frequency F3
- 82 Hz
Bass reflex (QB3 after Small)recommended
- Enclosure volume Vb
- 69.4 l
- Tuning frequency Fb
- 48 Hz
- Cut-off frequency F3
- 60 Hz
Vb is the required net internal volume, Fb the tuning frequency of the reflex port and F3 the frequency at which the level has dropped by 3 dB. Calculated approximation after Small. A starting point for simulation, not a finished build plan.
Comparable drivers
Same size, same type, Qts within ±30 %.
- FaitalPRO 21XL3000fs 30 Hz · Qts 0.25 · Vas 284.6 l · in the database
- Beyma 21QLEX1600Fefs 30 Hz · Qts 0.28 · Vas 309 l · in the shop
- 18 Sound 21LW2600fs 27 Hz · Qts 0.29 · Vas 332 l · in the database
- Beyma 21LEX1600Ndfs 30 Hz · Qts 0.29 · Vas 305 l · in the shop
- 18 Sound 21NLW9001fs 32 Hz · Qts 0.31 · Vas 244 l · in the database
Specifications
| Allgemein | |
|---|---|
| Manufacturer | 18SOUND |
| Category | Low Frequency |
| Series | LW |
| Magnet | Ferrite |
| Impedance (Ω) | 8 |
| Power handling (W) | 1000 |
| Sensitivity (dB) | 99 |
| Frequency from (Hz) | 24 |
| Frequency to (Hz) | 2000 |
| Abmessungen & Korb | |
|---|---|
| Diameter | 21 |
| Voice coil (inch) | 4 |
| Mounting depth (mm) | 259 |
| Weight (kg) | 17 |
| Thiele-Small-Parameter | |
|---|---|
| Re (Ω) | 5 |
| Le (mH) | 2.85 |
| Fs (Hz) | 28 |
| Qms | 9.32 |
| Qes | 0.24 |
| Qts | 0.24 |
| Vas (l) | 385 |
| Xmax (mm) | 9.5 |
| BL (Tm) | 33.5 |
| Mms (kg) | 0.296 |
| Sd (m²) | 0.166 |