18 Sound 8NTLS2000 – Long-Throw 8-Inch Neodymium Subwoofer with Tetracoil Motor and 7.4 mm Xmax at 1.5 kg
The 18 Sound 8NTLS2000 is the long-throw subwoofer variant of 18 Sound’s Tetracoil 8-inch platform — sharing the same 51 mm dual voice coil, the same 8.5 mm dual magnetic gap, the same neodymium motor, the same 1.5 kg weight, and the same physical dimensions as the 8NTLW2000 woofer, but with a deeper 19 mm voice coil winding that produces 68% more linear excursion. Where the 8NTLW2000 optimises for mid-bass sensitivity at 97.5 dB with 4.4 mm Xmax, the 18 Sound 8NTLS2000 optimises for bass displacement at 7.4 mm Xmax with 93.5 dB sensitivity — reaching down to 40 Hz from an 8-inch driver weighing 1.5 kg.
The 7.4 mm Xmax from a 1.5 kg 8-inch driver is the specification that defines the 18 Sound 8NTLS2000’s value. No other 18 Sound 8-inch driver delivers this much displacement at this weight. The 8NW650 achieves 5.5 mm Xmax at 2.4 kg. The 8NMB420 achieves 5.8 mm at 1.7 kg. The 18 Sound 8NTLS2000 achieves 7.4 mm at 1.5 kg — more displacement than any other 18 Sound 8-inch woofer, from the lightest 8-inch in the range.
The 41 Hz Fs is the lowest of any 18 Sound 8-inch driver — lower than the 8NW650’s 63 Hz, the 8NMB420’s 61 Hz, and the 8NTLW2000’s 71 Hz. The 40 Hz lower frequency limit means the 18 Sound 8NTLS2000 reaches into genuine sub-bass territory from an 8-inch frame. 18 Sound recommends a 12-litre enclosure tuned to 45 Hz — a compact sub-bass cabinet designed for the deepest possible output from the 8-inch format.
The engineering mechanism is the same as the 10NTLS2000 versus the 10NTLW2000: a deeper voice coil winding in the same dual gap. The 19 mm winding depth (versus 13 mm on the 8NTLW2000) provides more coil overhang above and below the 8.5 mm gap, which extends the linear excursion range at the cost of moving mass, sensitivity, and upper-frequency bandwidth. The trade-off is deliberate and transparent — every specification the 8NTLW2000 leads on (sensitivity, bandwidth, efficiency), the 18 Sound 8NTLS2000 trades for displacement and bass extension.
Available in 4, 8, and 16 Ω — the widest impedance range of any 18 Sound 8-inch Tetracoil driver.
Design and Construction of the 18 Sound 8NTLS2000
The 18 Sound 8NTLS2000 uses a 51 mm (2-inch) dual voice coil operating in the same Tetracoil (TTC) neodymium dual-gap motor as the 8NTLW2000. The motor is shared — same magnet assembly, same dual gap structure, same fundamental architecture. The voice coil winding is where the two drivers diverge.
The 19 mm winding depth is the engineering change that creates the displacement advantage. In the same 8.5 mm dual magnetic gap, a 19 mm winding has 10.5 mm of overhang (5.25 mm per side) versus the 8NTLW2000’s 13 mm winding with 4.5 mm of overhang (2.25 mm per side). The additional 6 mm of winding depth translates to 3 mm of additional linear excursion — 7.4 mm versus 4.4 mm. The mechanism is identical to what 18 Sound applies across the entire NTLW/NTLS family: same motor, deeper coil, more excursion.
The deeper winding adds conductor mass to the moving assembly. The 18 Sound 8NTLS2000’s 42 g moving mass is 50% heavier than the 8NTLW2000’s 28 g. Heavier moving mass means slower acceleration per unit of force, which reduces sensitivity — 93.5 dB versus the 8NTLW2000’s 97.5 dB. The 4 dB sensitivity reduction is the mathematical consequence of more coil mass.
The 17.2 Tm force factor is marginally lower than the 8NTLW2000’s 17.5 Tm — the coil sections furthest from the gap centre experience slightly weaker flux, averaging the force factor slightly downward. The 17.2 Tm driving 42 g still provides extreme motor authority — the Qts of 0.19 is the lowest of any 18 Sound 8-inch driver, even more motor-dominant than the already-extreme 8NTLW2000’s 0.21.
The Tetracoil dual-gap motor provides the same thermal and Bl symmetry advantages as the 8NTLW2000. The doubled coil surface in the magnetic field dissipates heat twice as efficiently as a single-gap design, sustaining the 350 W AES / 700 W program power rating — identical to the 8NTLW2000 despite the deeper coil. The symmetrical Bl shape maintains consistent force output across the extended 7.4 mm excursion range, keeping intermodulation distortion low at the high displacement levels that bass reproduction demands.
The single roll rubber surround replaces the 8NTLW2000’s double roll. The rubber material provides the compliance and excursion control needed for 7.4 mm Xmax with 8.0 mm Xvar — the longer stroke requires a more compliant surround that supports the additional travel. Rubber’s inherent weather resistance adds outdoor durability without surface treatment.
The curvilinear cone with weather-protected treatment maintains durability for outdoor applications. The 0.69 mH Le is slightly higher than the 8NTLW2000’s 0.63 mH — the deeper winding in the dual gap produces marginally more inductance. For the 1000 Hz upper bandwidth, the inductance is well-managed.
At 1.5 kg, 210 mm overall diameter, 186 mm baffle cutout, 121 mm depth, and 9 mm flange — every physical dimension matches the 8NTLW2000 exactly. The two drivers are completely interchangeable in the same cabinet.
Performance and Applications for the 18 Sound 8NTLS2000
The 18 Sound 8NTLS2000 delivers 93.5 dB sensitivity across a 40 Hz – 1000 Hz bandwidth. The 40 Hz lower frequency limit from an 8-inch driver weighing 1.5 kg is remarkable — it means the 18 Sound 8NTLS2000 reaches sub-bass frequencies that most 8-inch drivers can’t approach regardless of enclosure design.
The 7.4 mm Xmax combined with 227 cm² of radiating area produces approximately 168 cm³ of volume displacement — 68% more than the 8NTLW2000’s 100 cm³. For compact subwoofer applications where the 8-inch format is required, the 18 Sound 8NTLS2000 moves enough air for genuine low-frequency output that the 8NTLW2000’s shorter excursion can’t match.
18 Sound recommends a 12-litre (0.42 ft³) vented enclosure tuned to 45 Hz. The 45 Hz tuning targets deep bass output from the compact 8-inch format — a sub-bass alignment that produces useful content in the 40–80 Hz range where kick drums, bass instruments, and low-frequency effects live. The 12-litre cabinet is compact enough for portable subs, under-seat bass systems, and distributed bass applications.
The 0.19 Qts is the most extreme motor-dominant alignment of any 18 Sound 8-inch driver. The Tetracoil motor has total authority over the 42 g moving mass through the 7.4 mm excursion range — the bass is tight, fast, and precisely controlled even at maximum displacement. The 215 Hz EBP confirms a vented-only alignment — the 0.19 Qts would produce extremely thin response in a sealed enclosure.
The 1000 Hz upper bandwidth is appropriate for subwoofer and bass applications. The 18 Sound 8NTLS2000 operates well below the crossover point to a mid-bass or midrange driver. In a two-way system with a compact mid-high top, the sub section uses the 18 Sound 8NTLS2000 for everything below 200–500 Hz. In a three-way system, it handles the bass section exclusively.
The 4, 8, and 16 Ω impedance availability is the widest of any 18 Sound 8-inch Tetracoil. The 4 Ω variant maximises power transfer from the amplifier in single-driver sub applications. The 8 Ω is the professional standard. The 16 Ω enables multi-driver parallel and series-parallel configurations for compact sub arrays.
The physical interchangeability with the 8NTLW2000 is the system design advantage. One cabinet platform serves both drivers — the 8NTLW2000 for mid-bass sensitivity or the 18 Sound 8NTLS2000 for bass displacement. A product manufacturer can build a compact two-way top with the 8NTLW2000 and a compact sub with the 18 Sound 8NTLS2000, using the same cabinet platform for both.
The comparison to the 10NTLS2000 places the 8-inch sub variant in context. Both drivers share the same 51 mm coil, the same 19 mm winding depth, and the same 8.5 mm dual gap. The 10NTLS2000 has more cone area (346 vs 227 cm²) for more volume displacement, lower Fs (50 vs 41 Hz — actually the 8NTLS2000 has the lower Fs!), and 97 dB sensitivity (vs 93.5 dB). The 18 Sound 8NTLS2000 reaches deeper (41 vs 50 Hz Fs), weighs less (1.5 vs 1.9 kg), and has more extreme motor dominance (0.19 vs 0.26 Qts). The 8-inch sub goes deeper by Fs but has less displacement area. The 10-inch sub has more total bass output from the larger cone.
Conclusion – 18 Sound 8NTLS2000 Subwoofer Driver
The 18 Sound 8NTLS2000 is the displacement variant of 18 Sound’s Tetracoil 8-inch platform — the same motor, the same body, the same 1.5 kg weight as the 8NTLW2000 woofer, but with a 19 mm winding depth that produces 7.4 mm of linear excursion versus the woofer’s 4.4 mm. The engineering trade-off is the same clean exchange applied across the entire NTLW/NTLS family: 68% more displacement in exchange for 4 dB less sensitivity and 3500 Hz less upper bandwidth.
The 1.5 kg weight with 7.4 mm Xmax is the 18 Sound 8NTLS2000’s most compelling specification. No other 18 Sound 8-inch driver delivers this much displacement at this weight. The 41 Hz Fs is the lowest of any 18 Sound 8-inch. The 0.19 Qts is the most motor-dominant. The 4/8/16 Ω availability is the widest. The physical interchangeability with the 8NTLW2000 gives system designers a matched woofer/sub pair from the same 1.5 kg cabinet platform.
For compact sub cabinets, distributed bass systems, under-seat subs, line array bass elements, and any application where an 8-inch driver needs to deliver maximum bass displacement from 1.5 kg, the 18 Sound 8NTLS2000 is the sub half of the lightest 8-inch Tetracoil platform. Same motor, same body, same weight — deeper coil, deeper bass, more displacement. The sub half of the lightest 8-inch in professional audio.
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About 18 Sound
18 Sound products are proudly made in Reggio Emilia, Italy, combining advanced technology with Italian craftsmanship. Known for their high-performance professional audio components, 18 Sound is a trusted name in the global audio industry. Their state-of-the-art manufacturing and strict quality control ensure exceptional reliability and sound clarity. 18 Sound products are designed to meet the demands of speaker builders and audio professionals, 18 Sound offers premium products with outstanding value and performance worldwide.
