18 Sound 10NCX750H – Coaxial Driver

18 Sound 10NCX750H – Asymmetric-Dispersion 10-Inch Neodymium Coaxial with 70° × 50° Coverage and 15-Litre Enclosure

The 18 Sound 10NCX750H is the asymmetric-dispersion variant of 18 Sound’s neodymium 10-inch coaxial platform. Where the 10NCX750 produces an 80° conical pattern, the 18 Sound 10NCX750H produces a 70° × 50° asymmetric pattern — wider horizontal for audience coverage, tighter vertical for controlled spill. The 18 Sound 10NCX750H carries the same 75 mm ISV copper LF coil, the same SDR, the same 64 mm EWAL titanium HF section, and the same 15-litre minimum enclosure as the conical 10NCX750. And unlike every other H variant in 18 Sound’s coaxial range, the 18 Sound 10NCX750H weighs the same as its conical sibling — 4.25 kg, with no weight penalty for the asymmetric coverage.

The 70° × 50° pattern matches the 12NCX750H and 15NCX750H — the same asymmetric coverage geometry scaled to the 10-inch format. The consistent 70° × 50° across all three sizes means system designers can specify 10, 12, and 15-inch coaxials with identical coverage patterns for different output levels, producing visually and acoustically matched multi-format systems.

The LF sensitivity of 95 dB is 2.5 dB below the 10NCX750’s 97.5 dB — the largest LF sensitivity reduction of any H variant in the coaxial range (the 12NCX750H drops 1.7 dB, the 15NCX750H drops 1 dB). The different cone-waveguide profile needed for asymmetric HF dispersion affects the 10-inch LF section’s acoustic behaviour more significantly than it does on the larger formats — the smaller cone has less physical area to absorb the geometry changes, so the LF performance impact is proportionally greater.

The HF sensitivity remains at 105 dB — unchanged from the conical 10NCX750. This is the opposite behaviour from the 12 and 15-inch H variants, where the tighter asymmetric pattern concentrated HF energy for higher HF sensitivity. At the 10-inch scale, the asymmetric exit geometry produces the directivity change without the concentration gain that the larger formats exhibit.

At 4.25 kg, 260 mm overall diameter, 230 mm baffle cutout, 148 mm depth, and 15-litre minimum enclosure, the 18 Sound 10NCX750H delivers PA-optimised asymmetric coverage from the lightest, most compact neodymium coaxial platform in 18 Sound’s range.

Design and Construction of the 18 Sound 10NCX750H

The 18 Sound 10NCX750H shares the 10NCX750’s core platform — the same single neodymium magnet motor, the same 75 mm copper ISV coil, the same aluminium SDR, and the same 64 mm EWAL titanium HF section with 3P tangerine phase plug. The difference is the HF exit profile and cone-waveguide geometry that produce the asymmetric 70° × 50° pattern.

The LF section uses the same 75 mm (3-inch) copper ISV voice coil with 15 mm winding depth operating in a 7.6 mm magnetic gap. The ISV places conductor on both surfaces of the former for mass-balanced, linear motor behaviour. The copper winding sustains the 350 W AES / 700 W program power rating. The aluminium SDR reduces flux modulation during excursion.

The 19.8 Tm force factor driving 47 g of moving mass produces 95 dB LF sensitivity and 2.2% reference efficiency. The 2.5 dB lower LF sensitivity versus the 10NCX750’s 97.5 dB is the most significant performance trade-off of any H variant in the range. The different cone profile needed for asymmetric HF dispersion changes the LF acoustic loading — the cone-waveguide geometry optimised for 70° × 50° HF coverage extracts less LF output per watt than the conical 80° profile.

The Qts of 0.25 and EBP of 250 Hz are essentially identical to the 10NCX750’s 0.25 and 246 Hz — the motor dominance and enclosure alignment are unchanged. The 15-litre minimum enclosure recommendation is the same. The T/S parameters that govern bass behaviour are preserved across both variants.

The curvilinear LF cone with water-repellent treatment and corrosion-resistant plate coatings provides outdoor durability. The 5.5 mm Xmax with 7 mm Xvar matches the conical variant.

The HF section uses the identical 64 mm (2.5-inch) EWAL voice coil, titanium diaphragm with Nomex bent edge former, copper sleeve, and 3P tangerine phase plug. The 105 dB HF sensitivity and 70 W AES / 140 W program power handling are unchanged from the 10NCX750.

The HF exit profile is the modification that creates the asymmetric pattern. The exit geometry shapes the compression driver’s output into the 70° × 50° window as it couples with the modified cone-waveguide. Unlike the 12NCX750H (+3.3 dB HF) and 15NCX750H (+1.5 dB HF), the 10-inch H variant doesn’t gain HF sensitivity from the tighter pattern. The 10-inch cone’s smaller surface area may not provide enough waveguide length for the concentration effect that the larger formats achieve — the HF energy enters and exits the cone-waveguide over a shorter path, limiting the degree of concentration the asymmetric geometry can produce.

The 4.25 kg weight is identical to the conical 10NCX750 — the only H variant in the range that adds no weight. The 12NCX750H adds 200 g (4.7 vs 4.5 kg). The 15NCX750H adds 400 g (5.3 vs 4.9 kg). At the 10-inch scale, the asymmetric modifications fit within the same weight envelope. The 260 mm overall diameter, 230 mm baffle cutout, 148 mm depth, and 14 mm flange are all identical — the two 10-inch variants are completely interchangeable.

Performance and Applications for the 18 Sound 10NCX750H

The 18 Sound 10NCX750H delivers 95 dB LF sensitivity from 60 Hz and 105 dB HF sensitivity from the 1.2 kHz crossover point upward. The 10 dB sensitivity difference between sections is managed through the crossover network.

The 70° × 50° asymmetric dispersion changes the application space from the conical 10NCX750. The 70° horizontal covers a moderately wide listening area. The 50° vertical focuses energy on the audience plane with more precision than the 10NCX750’s 80° conical — reducing ceiling reflections, floor bounce, and spill beyond the intended coverage boundary.

The asymmetric pattern is the dispersion geometry that compact PA tops and installed speakers need. Where the 10NCX750’s 80° conical provides equal coverage in every direction — ideal for stage monitors and ceiling-mounted speakers — the 18 Sound 10NCX750H’s 70° × 50° provides the wider-horizontal, tighter-vertical coverage that front-of-house PA, under-balcony fill, and wall-mounted installed speakers require. The horizontal coverage fills the seating area. The vertical coverage controls where the sound goes and where it doesn’t.

The 95 dB LF sensitivity is the trade-off for the asymmetric coverage. At 350 W AES, the maximum sustained LF output is approximately 2.5 dB lower than the conical 10NCX750 at the same power. For compact PA tops where the 10-inch driver operates with a sub system handling the deep bass, the mid-bass and mid-range output at 95 dB sensitivity remains competitive — and the asymmetric coverage ensures the output reaches the audience with better vertical control.

The 15-litre minimum enclosure is the same as the conical 10NCX750 — the smallest of any 18 Sound coaxial. The 0.25 Qts and 250 Hz EBP maintain the same extreme motor dominance and vented-enclosure alignment. A 15-litre vented cabinet with the 18 Sound 10NCX750H produces a complete asymmetric-coverage two-way coaxial point source in the most compact format 18 Sound offers.

The 4.25 kg weight with no penalty for the asymmetric modification is a practical advantage that the 12 and 15-inch H variants don’t share. Builders can choose between conical and asymmetric coverage in the 10-inch format without any weight compromise — the two drivers are identical in weight, dimensions, and mounting requirements.

The consistent 70° × 50° coverage across 18 Sound’s H variants — 10NCX750H, 12NCX750H, and 15NCX750H — enables matched-coverage multi-format systems. A compact PA installation might use 15NCX750H cabinets for the main system, 12NCX750H for delays, and 18 Sound 10NCX750H for under-balcony fill — all producing the same 70° × 50° coverage pattern at different output levels. The coverage geometry is consistent across the venue; only the output and bass extension change with format size.

Conclusion – 18 Sound 10NCX750H Coaxial Driver

The 18 Sound 10NCX750H is the most compact asymmetric-coverage coaxial in 18 Sound’s range. The 70° × 50° pattern provides the wider-horizontal, tighter-vertical coverage that PA and installed sound applications demand, from a 10-inch neodymium coaxial weighing 4.25 kg — the same weight as the conical 10NCX750, with no penalty for the asymmetric modification.

The 95 dB LF sensitivity is the honest trade-off — the largest LF sensitivity reduction of any H variant, reflecting the 10-inch cone’s greater sensitivity to the waveguide geometry changes that asymmetric dispersion requires. The 105 dB HF sensitivity is unchanged from the conical variant — the 10-inch format doesn’t gain HF concentration from the tighter pattern the way the larger formats do.

The 15-litre minimum enclosure, 0.25 Qts motor dominance, 0.54 mH inductance, and 148 mm depth remain the same. The 10NCX750H and 10NCX750 are physically identical and completely interchangeable — one cabinet, two coverage options, 4.25 kg either way.

For compact PA tops, under-balcony fills, wall-mounted installed speakers, and any application where a 10-inch coaxial needs asymmetric 70° × 50° coverage from a 15-litre enclosure at 4.25 kg, the 18 Sound 10NCX750H is the smallest, lightest asymmetric coaxial point source in 18 Sound’s catalogue. Same weight as the conical, same enclosure, same depth — different coverage, different application, same lightest-neodymium-coaxial weight class.