18SOUND 21NLW4100
18SOUND (Eighteen Sound) 21NLW4100 — 21" / 21 inch · High-Performance Woofer · Subwoofer / Bass · Neodymium
4" voice coil · 4 Ω
Part no.: 42A-CHS-TT-18S-0035
Documents
18SOUND 21NLW4100 — 21" · Woofer
1500 W AES · 97 dB Sensitivity · Frequency range 32 Hz – 300 Hz
Technical data
- Diameter: 21 "
- Voice coil: 4 "
- Power handling: 1500 W AES
- Sensitivity: 97 dB
- Impedance: 4 Ω
- Magnet: Neo
- Weight: 10.5 kg
- Mounting depth: 245 mm
- Frequency range: 32 – 300 Hz
Datasheet (PDF) · Manufacturer page
Series: NLW · Part no.: 42A-CHS-TT-18S-0035
18Sound 21NLW4100: 21" neodymium subwoofer with 15.2 mm Xmax at just 10.5 kg
10.5 kg for a 21" driver rated at 1500 W – the 21NLW4100 from 18Sound's NLW series shows what neodymium does for a motor. The 4" voice coil is wound for 4 Ω (Re 2.6 Ω), sensitivity is 97 dB and linear excursion 15.2 mm. The 32 to 300 Hz operating range makes it clear: this is a pure subwoofer driver.
The parameters fs 34 Hz, Qts 0.4 and Vas 219 l give a medium Q that also allows sealed enclosures. BL 22.8 Tm with Mms 0.4 kg is a moderate motor – the 21NLW4100 relies less on motor strength than on cone area (Sd 0.1661 m²) and excursion. For mobile subwoofers where every kilo counts, the combination of weight, excursion and power handling is the argument.
Use and enclosure
EBP 81 – both bass reflex and sealed are possible. The bass reflex guideline: about 237 l tuned to 33 Hz with f3 around 32 Hz, so deep bass without equalisation, but in a big box. Sealed, around 103 l with fc at 60 Hz is a compact alternative where the system amplifier's DSP equalisation restores the extension; 15.2 mm Xmax provides the reserve for that. The enclosure calculator at 42.audio shows how smaller reflex volumes with higher tuning behave.
At 4 Ω nominal a single driver makes good use of a PA amplifier's power; for dual-21 cabinets you need to plan the wiring, since two parallel 4 Ω drivers overload most amplifiers. The 245 mm mounting depth is uncritical.
What to look out for
- 4 Ω, Re 2.6 Ω: for multiple drivers plan series wiring or separate channels
- Only 10.5 kg thanks to neodymium – ideal for mobile subwoofers
- Xmax 15.2 mm, power handling 1500 W
- Qts 0.4: sealed boxes with equalisation are a genuine option
- Operating range 32–300 Hz, pure subwoofer use
Frequently asked questions
How does the 21NLW4100 differ from the 21NLW5300?
The 21NLW5300 with Qts 0.32 and 325 l Vas is closer to a classic reflex sub, the 21NLW4100 with Qts 0.4 and 219 l has a higher Q and smaller Vas. That makes the 4100 more flexible in sealed or smaller boxes, and considerably lighter.
Which amplifier suits 4 Ω?
An amplifier that delivers around 1500 W continuously at 4 Ω. Two drivers in series give 8 Ω and can run on one channel; in parallel you would get 2 Ω, which most amplifiers cannot handle.
Does this driver make sense for home cinema?
Yes, especially sealed: around 103 l with fc at 60 Hz and DSP equalisation gives controlled deep bass, and 15.2 mm Xmax provides the necessary displacement. Bass reflex at 237 l gives more output without equalisation.
At 42.audio you get the 18SOUND 21NLW4100 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 | 4 Ω |
|---|---|
| Resonance frequency fs | 34 Hz |
| Total Q Qts | 0.4 |
| Electrical Q Qes | 0.42 |
| Mechanical Q Qms | 7.8 |
| Equivalent volume Vas | 219.0 l |
| Moving mass Mms | 400.0 g |
| Cone area Sd | 1,661 cm² |
| Linear excursion Xmax | 15.2 mm |
| Force factor BL | 22.8 Tm |
| DC resistance Re | 2.6 Ω |
| Voice coil inductance Le | 1.5 mH |
Enclosure suggestion
The EBP of 81 is in the intermediate range — either works; sealed plays tighter, bass reflex deeper and louder. EBP = fs / Qes = 34 / 0.42
Sealed (Qtc 0.707)
- Enclosure volume Vb
- 103.1 l
- System resonance Fc
- 60 Hz
- Cut-off frequency F3
- 60 Hz
Bass reflex (QB3 after Small)
- Enclosure volume Vb
- 212.9 l
- Tuning frequency Fb
- 34 Hz
- Cut-off frequency F3
- 34 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 %.
- 18 Sound 21NTLW5000fs 31 Hz · Qts 0.36 · Vas 270 l · in the shop
- 18 Sound 21NLW5300fs 31 Hz · Qts 0.32 · Vas 325 l · in the shop
- 18 Sound 21NTLW5000fs 30 Hz · Qts 0.32 · Vas 300 l · in the database
- 18 Sound 21LW2600fs 27 Hz · Qts 0.33 · Vas 333 l · in the shop
- 18 Sound 21NLW9001fs 32 Hz · Qts 0.31 · Vas 244 l · in the database
- Beyma 21LEX1600Ndfs 30 Hz · Qts 0.29 · Vas 305 l · in the shop
Specifications
| Allgemein | |
|---|---|
| Manufacturer | 18SOUND |
| Category | Low Frequency |
| Series | NLW |
| Magnet | Neo |
| Impedance (Ω) | 4 |
| Power handling (W) | 1500 |
| Sensitivity (dB) | 97 |
| Frequency from (Hz) | 32 |
| Frequency to (Hz) | 300 |
| Abmessungen & Korb | |
|---|---|
| Diameter | 21 |
| Voice coil (inch) | 4 |
| Mounting depth (mm) | 245 |
| Weight (kg) | 10.5 |
| Thiele-Small-Parameter | |
|---|---|
| Re (Ω) | 2.6 |
| Le (mH) | 1.5 |
| Fs (Hz) | 34 |
| Qms | 7.8 |
| Qes | 0.42 |
| Qts | 0.4 |
| Vas (l) | 219 |
| Xmax (mm) | 15.2 |
| BL (Tm) | 22.8 |
| Mms (kg) | 0.4 |
| Sd (m²) | 0.1661 |