18SOUND 12NTLW2500
18SOUND (Eighteen Sound) 12NTLW2500 — 12" / 12 inch · Woofer/Midrange (WM) · Bass · Neodymium · Dual-Gap
2x2.5" voice coil · 4 Ω
Part no.: 42A-CHS-TT-18S-0060
Documents
18SOUND 12NTLW2500 — 12" · Woofer
500 W AES · 97.5 dB Sensitivity · Frequency range 55 Hz – 4500 Hz
Technical data
- Diameter: 12 "
- Voice coil: 2.5 "
- Power handling: 500 W AES
- Sensitivity: 97.5 dB
- Impedance: 4 Ω
- Magnet: Neo
- Weight: 3.6 kg
- Mounting depth: 175 mm
- Frequency range: 55 – 4500 Hz
Datasheet (PDF) · Manufacturer page
Series: NTLW · Part no.: 42A-CHS-TT-18S-0060
18Sound 12NTLW2500: 3.6 kg 12" dual-gap woofer with 4 Ω and 97.5 dB
At 3.6 kg the 18Sound 12NTLW2500 is the lightest 12" driver in this range. That is made possible by a neodymium dual-gap motor with a 2x2.5" voice coil which, despite its compact build, handles 500 W AES and reaches 97.5 dB sensitivity. This version is the 4 Ω variant with Re 2.8 Ω; the woofer is also made in 8 and 16 Ω.
The inductance of only 0.31 mH is the most striking figure: the double-gap construction keeps impedance flat well into the midrange, which is what makes the 55 to 4,500 Hz frequency range usable in the first place. Fs 52 Hz, Qts 0.31, Vas 52.7 l, Xmax 7.6 mm and a moving mass of 71 g complete the picture of a fast, light woofer/midrange driver. The Qms of 10.2 indicates low mechanical losses in the suspension.
Use and enclosure
With an EBP of 162 bass reflex is the way to go. The guideline is 27 l net tuned to 63 Hz with an f3 around 70 Hz – a lightweight top working above a subwoofer, or a stage monitor where weight matters. A sealed volume of 13 l gives a 119 Hz system resonance and fits as a low-mid chamber in a 3-way system. The enclosure calculator on 42.audio lets you refine the tuning.
Because of the 4 Ω, choose the amplifier deliberately: two of these drivers in parallel would be 2 Ω, which many amplifiers cannot drive reliably. In series you get 8 Ω, but then you lose the level headroom. For the crossover to the tweeter there is room up to 4,500 Hz; a 1" compression driver with a horn from the 18Sound range is the obvious complement, and the low Le keeps the passive network simple.
What to look out for
- 4 Ω, Re 2.8 Ω – the amplifier must be load-stable, avoid parallel wiring.
- 3.6 kg: the lightest 12" driver in this range.
- Le 0.31 mH thanks to the dual-gap motor – usable up to 4,500 Hz.
- Mounting depth 175 mm despite the low weight.
- Xmax 7.6 mm, 500 W AES.
Frequently asked questions
Why is the 12NTLW2500 listed here with 4 Ω?
This version is the 4 Ω model with Re 2.8 Ω. The woofer also exists in 8 and 16 Ω. The 4 Ω draws more power from an amplifier but requires one that stays clean into this load.
How does it compare with the Beyma 12LEX1000Fe?
Both have a Qts around 0.3 and similar resonance frequencies (52 versus 49 Hz). The Beyma has a smaller Vas of 38.4 l versus 52.7 l for the 18Sound and is a ferrite driver, so considerably heavier. Details on both are in the driver database on 42.audio.
Is the 12NTLW2500 suitable as a midrange driver?
Yes, in a sealed chamber around 13 l it is a very good low-mid driver for a 3-way system. The 0.31 mH inductance and the 71 g cone mass ensure it works cleanly up to 4,500 Hz without impedance issues.
At 42.audio you get the 18SOUND 12NTLW2500 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 | 52 Hz |
| Total Q Qts | 0.31 |
| Electrical Q Qes | 0.32 |
| Mechanical Q Qms | 10.2 |
| Equivalent volume Vas | 52.7 l |
| Moving mass Mms | 71.0 g |
| Cone area Sd | 531 cm² |
| Linear excursion Xmax | 7.6 mm |
| Force factor BL | 14.4 Tm |
| DC resistance Re | 2.8 Ω |
| Voice coil inductance Le | 0.31 mH |
Enclosure suggestion
The EBP of 162 suggests a bass-reflex enclosure. EBP = fs / Qes = 52 / 0.32
Sealed (Qtc 0.707)
- Enclosure volume Vb
- 12.5 l
- System resonance Fc
- 119 Hz
- Cut-off frequency F3
- 119 Hz
Bass reflex (QB3 after Small)recommended
- Enclosure volume Vb
- 22.1 l
- Tuning frequency Fb
- 68 Hz
- Cut-off frequency F3
- 76 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 %.
- B&C Speakers 12CL64fs 52 Hz · Qts 0.3 · Vas 64 l · in the database
- B&C Speakers 12FL76fs 50 Hz · Qts 0.3 · Vas 57 l · in the database
- Beyma 12LEX1000Fefs 49 Hz · Qts 0.3 · Vas 38.4 l · in the shop
- PRV Audio 12MB2000FT-NDYfs 55.1 Hz · Qts 0.3 · Vas 71.5 l · in the database
- PRV Audio 12MB2000FTfs 55.6 Hz · Qts 0.32 · Vas 66.9 l · in the database
- Ciare PW328fs 48 Hz · Qts 0.32 · Vas 91 l · in the database
Specifications
| Allgemein | |
|---|---|
| Manufacturer | 18SOUND |
| Category | Low Frequency |
| Series | NTLW |
| Magnet | Neo |
| Impedance (Ω) | 4 |
| Power handling (W) | 500 |
| Sensitivity (dB) | 97.5 |
| Frequency from (Hz) | 55 |
| Frequency to (Hz) | 4500 |
| Abmessungen & Korb | |
|---|---|
| Diameter | 12 |
| Voice coil (inch) | 2.5 |
| Mounting depth (mm) | 175 |
| Weight (kg) | 3.6 |
| Thiele-Small-Parameter | |
|---|---|
| Re (Ω) | 2.8 |
| Le (mH) | 0.31 |
| Fs (Hz) | 52 |
| Qms | 10.2 |
| Qes | 0.32 |
| Qts | 0.31 |
| Vas (l) | 52.7 |
| Xmax (mm) | 7.6 |
| BL (Tm) | 14.4 |
| Mms (kg) | 0.071 |
| Sd (m²) | 0.0531 |