18 Sound 15ND730 – High-Output 15-Inch Neodymium Woofer with User-Serviceable Heatsink Mounting
The 18 Sound 15ND730 transducer has been designed to meet market demand for high-output woofers, capable of providing deep bottom-end in bandpass, horns, or small reflex enclosures. The level of distortion is kept very low within its application range — the same design brief documented on the 12ND730 earlier in this session, here scaled to 15 inches.
The 18 Sound 15ND730 is suitable for high-loading enclosures, such as subwoofers or two-way system reflex enclosures when coupled with a 1.4-inch to 2-inch compression driver. The four threaded backplate holes allow the final user the possibility to insert an external-customised heatsink if further heat dissipation is required — the same distinctive modular thermal management approach documented on the 12ND730, giving system integrators direct control over the driver’s thermal ceiling based on their specific deployment rather than a fixed factory cooling solution.
The neodymium magnet assembly developed by 18 Sound engineers assures high flux concentration, low power compression, and excellent heat exchange, since the external magnet configuration is considerably more efficient than traditional under-pole magnet topology. A single demodulating ring, appropriately positioned in the magnetic circuit, allows a further flux modulation reduction, keeping overall distortions at a low level when driven hard.
At just 3.9 kg — the lightest of any conventional 15-inch ND-series driver documented across this entire session, lighter than the 15ND830 (4.6 kg), 15ND840/930/940 (all 4.7 kg) — the 18 Sound 15ND730 combines high force factor with the lightest weight in this driver family.
Design and Construction of the 18 Sound 15ND730
The 75 mm Interleaved Sandwich Voice Coil (ISV) assembly is wound on a strong fibreglass former which improves force transmission and thermal power handling. A single demodulating ring, appropriately positioned in the magnetic circuit, allows a further flux modulation reduction, keeping overall distortions at a low level when driven hard.
The deep-profile curvilinear cone, created from a special high-strength wood pulp, has been designed to achieve the best possible linearity within its frequency range. The cone surround, made from a linen material, is highly resistant to ageing and fatigue. The in-house developed cone treatment is fully water repellent and also gives a significant degree of rigidity to the cone.
The four threaded backplate holes are the driver’s signature engineering feature, allowing the final user the possibility to insert an external-customised heatsink if further heat dissipation is required — the same modular cooling philosophy documented on the 12ND730, here scaled to the 15-inch format.
The 21.0 Tm force factor driving 86 g of moving mass produces 99 dB sensitivity and the 0.29 Qts / 146 Hz EBP alignment — solidly motor-dominant and vented-oriented.
A special coating applied to both the top and back plates makes the 18 Sound 15ND730 far more resistant to the corrosive effects of salts and oxidisation.
At 3.9 kg, 387 mm overall diameter, 353 mm baffle cutout, and 169 mm depth, the 18 Sound 15ND730 is the lightest conventional ND-series driver in this comparison — 700–800 g lighter than every other neodymium ND-series 15-inch driver documented in this session.
Performance and Applications for the 18 Sound 15ND730
The 18 Sound 15ND730 delivers 99 dB sensitivity across a 44 Hz – 4000 Hz bandwidth. 18 Sound recommends a 100-litre (3.53 ft³) vented enclosure tuned to 50 Hz.
The 400 W AES / 600 W continuous program power handling, combined with the optional user-installed heatsink capability, gives system integrators genuine control over the driver’s thermal ceiling based on their specific deployment — for applications running at moderate power where standard cooling suffices, no additional heatsink is needed; for sustained high-power touring or installed applications, the four threaded backplate holes provide a straightforward mounting solution for supplementary cooling.
The 44 Hz lower frequency limit and 44 Hz Fs are appropriate for the bandpass, horn, and small reflex enclosure applications this driver targets, providing deep bottom-end reproduction as 18 Sound specifically states.
For applications where minimum weight matters within the ND-series family — touring rigs, multi-cabinet installations, or systems where cumulative driver weight compounds across many units — the 18 Sound 15ND730’s 3.9 kg is a genuine advantage over every other conventional 15-inch ND-series driver documented in this session.
Conclusion – 18 Sound 15ND730 Woofer
The 18 Sound 15ND730 was designed to meet market demand for high-output woofers capable of providing deep bottom-end in bandpass, horn, or small reflex enclosures — and at 3.9 kg, it delivers this brief as the lightest driver in 18 Sound’s 15-inch ND-series family. The four threaded backplate holes offering optional external heatsink installation give system integrators direct control over thermal management, the same distinctive approach documented on the 12ND730 at the smaller diameter.
For high-loading subwoofer enclosures, two-way reflex systems with 1.4-inch to 2-inch compression drivers, and applications where minimum weight within the ND-series family is the priority, the 18 Sound 15ND730 delivers a genuinely capable, lightweight specification.
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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.
