18 Sound 10CX650 – Compact 10-Inch Ferrite Coaxial with PEN HF Diaphragm, 90° Coverage, and Atmos-Ready Design
The 18 Sound 10CX650 is 18 Sound’s most compact coaxial transducer — a 10-inch point-source driver that delivers 94 dB LF sensitivity, 106.5 dB HF sensitivity, 90° conical dispersion, and Dolby Atmos-ready performance from a ferrite-motored platform designed for compact reflex enclosures as small as 30 litres. Where 18 Sound’s 12 and 15-inch coaxials use neodymium motors and titanium or beryllium HF diaphragms, the 18 Sound 10CX650 takes a fundamentally different approach — a high-force ceramic (ferrite) single magnet motor with a PEN (Polyethylene Naphthalate) polymer HF diaphragm that delivers smooth, natural treble without metal diaphragm resonances.
The 90° conical dispersion is the widest of any coaxial in 18 Sound’s range. No other 18 Sound coaxial achieves 90° — the largest 15-inch models top out at 80° conical or 90° on the 15NCX1000’s 90°. The 18 Sound 10CX650 matches or exceeds all of them on coverage angle, producing the broadest listening area of any 18 Sound point-source coaxial from the smallest format.
The 90° coverage and Atmos-ready designation place the 18 Sound 10CX650 in a specific application space. Dolby Atmos immersive audio installations require speakers mounted overhead — on ceilings and high walls — covering wide areas below them with consistent, uniform dispersion. The 90° conical pattern radiates equally in every direction from the acoustic centre, producing the wide, symmetrical coverage that immersive ceiling channels demand. The 18 Sound 10CX650’s coaxial architecture ensures the coverage is coherent across frequency — no lobing, no comb-filtering, uniform tonal balance at every angle within the 90° window.
The PEN HF diaphragm is a material choice that sets the 18 Sound 10CX650 apart from every other coaxial in the range. PEN is a high-performance engineering polymer with a very high elasticity modulus — stiffer than standard polyester but without the metallic resonances of titanium. The result is treble that sounds smooth and natural with superior transient and intermodulation distortion response — detailed without harshness, present without fatigue.
At 6.2 kg with a ferrite single magnet motor, 65 mm edgewound copper ISV LF coil, 44 mm EWAL HF section with 3P tangerine phase plug, and suitability for enclosures from 30 litres, the 18 Sound 10CX650 is the most compact and widest-coverage coaxial in 18 Sound’s catalogue.
Design and Construction of the 18 Sound 10CX650
The 18 Sound 10CX650 integrates a two-way coaxial transducer system into a single chassis powered by a single ceramic (ferrite) magnet motor. The ferrite motor is the structural departure from the neodymium-powered 12 and 15-inch coaxials. Ferrite provides the magnetic force at lower material cost but higher weight — the 18 Sound 10CX650 weighs 6.2 kg, which is heavier than the neodymium 12NCX750 (4.5 kg) despite being a smaller 10-inch format. The trade-off is cost — ferrite motors are significantly less expensive than neodymium.
The LF section uses a 65 mm (2.5-inch) edgewound copper ISV (Interleaved Sandwich Voice Coil) wound on a high-strength fibreglass former. The edgewound copper construction packs more conductor into the gap per unit of coil height, maximising force output. The ISV architecture places conductor on both surfaces of the former for mass-balanced, linear motor behaviour.
The 14 Tm force factor driving 39.5 g of moving mass produces 94 dB LF sensitivity and 1.5% reference efficiency. The 94 dB is lower than the 12-inch coaxials (97–99.5 dB) — the 10-inch format’s smaller cone area and the ferrite motor’s different flux characteristics account for the difference. For the 10-inch coaxial format, 94 dB is a competitive figure.
The curvilinear LF cone uses a low-profile design that provides smooth response within the LF operating range and maximum reliability under high mechanical stress. The humidity-repellent treatment provides outdoor durability. The 6 mm Xmax provides solid displacement capability for the 10-inch format.
The 60 Hz – 4800 Hz LF bandwidth is the widest of any 18 Sound coaxial LF section except the 12NCX750’s 5000 Hz. The 4800 Hz upper limit provides extensive overlap with the HF section above the 1.6 kHz crossover — over two octaves of overlap for smooth crossover transitions.
The 0.35 Qts and 138 Hz EBP define a versatile alignment that works in both sealed and vented enclosures. The EBP of 138 Hz sits on the sealed/vented boundary — the most flexible alignment in the coaxial range. 18 Sound specifies enclosures from 30 litres.
The HF section uses a 44 mm (1.75-inch) EWAL (Edge-Wound Aluminium) voice coil driving a PEN (Polyethylene Naphthalate) diaphragm. PEN is a high-performance engineering polymer related to PET (polyester) but with significantly higher mechanical properties. 18 Sound highlights several advantages of PEN for this application.
Superior dimensional stability — the PEN dome maintains consistent shape and behaviour throughout its entire working life. Where some polymer diaphragms can creep or deform over years of use, PEN resists dimensional change.
Very high elasticity modulus — PEN is stiffer than standard polyesters, which translates to superior transient response and lower intermodulation distortion. The diaphragm responds faster to electrical input, producing tighter, more defined treble output.
No metallic resonance — unlike titanium, PEN doesn’t produce a resonant breakup peak in the upper treble. The result is smooth, naturally extended high-frequency response that doesn’t need corrective EQ.
The flat suspension shape on the PEN dome is designed to maintain low stiffness and low mid-band distortion — keeping the dome compliant where it needs to move and controlled where it needs to stay rigid.
The EWAL coil is wound on a proprietary treated Nomex former. 18 Sound specifically highlights that the treated Nomex shows 30% higher tensile elongation at working operative temperature compared to Kapton. This means the former stretches rather than cracking under the thermal stress of sustained operation — enabling proper energy transfer control from the voice coil to the dome in real working conditions. The Nomex is also suitable for use in damp and wet environments, adding to the 18 Sound 10CX650’s outdoor durability.
A copper sleeve on the HF pole piece reduces inductance above 10 kHz for improved phase and impedance linearisation. The proprietary 3P hybrid radial tangerine phase plug produces smooth wavefronts with low distortion and high manufacturing consistency. The specific HF throat design maximises coupling between the compression driver output and the 10-inch LF cone’s profile, shaping the combined 90° conical dispersion.
At 6.2 kg, 260 mm overall diameter, 230 mm baffle cutout, and 155 mm depth, the 18 Sound 10CX650 fits standard 10-inch cabinet designs. The 8 mm flange thickness is the thinnest of any 18 Sound coaxial.
Performance and Applications for the 18 Sound 10CX650
The 18 Sound 10CX650 delivers 94 dB LF sensitivity from 60 Hz to 4800 Hz and 106.5 dB HF sensitivity from the 1.6 kHz crossover point upward. The 12.5 dB sensitivity difference between sections is managed through the crossover network, with the HF section padded to match the LF output level.
The 90° conical dispersion is the 18 Sound 10CX650’s defining coverage characteristic. The 90° pattern provides the widest coverage of any 18 Sound coaxial — equal in every direction, producing a broad, symmetrical listening window. For installations where the speaker covers a wide area from a single mounting position — ceiling-mounted Atmos channels, distributed sound systems, wide-coverage background music — the 90° conical pattern ensures uniform coverage without the directivity gaps that narrower-coverage speakers create.
The Atmos-ready designation confirms 18 Sound designed and validated the 18 Sound 10CX650 for immersive audio installations. Dolby Atmos systems use ceiling-mounted and elevated speakers to create the overhead sound field that immersive content requires. These speakers need wide, uniform dispersion to cover the listening area below them, and the coaxial point-source architecture ensures the coverage is coherent across frequency — critical for the spatial accuracy that Atmos content demands.
The PEN HF diaphragm’s smooth treble character is particularly valuable in Atmos and installed sound applications where the speakers operate at moderate power levels for extended periods. Metal diaphragm resonances can become fatiguing during extended listening — PEN’s polymer construction eliminates this issue entirely. The audience hears smooth, natural treble that stays comfortable from the first minute to the last hour.
The 200 W AES / 400 W program LF power handling and 70 W AES / 140 W HF power handling are appropriate for the compact PA, installed sound, and monitoring applications the 18 Sound 10CX650 targets. The 200 W AES is adequate for 10-inch format systems operating at moderate to high power levels.
The 0.35 Qts provides the most flexible enclosure alignment of any 18 Sound coaxial alongside the 15NCX750 (0.37 Qts). Builders can design sealed enclosures for tighter transient response or vented enclosures for more bass extension. The 54 Hz Fs and 60 Hz lower frequency limit confirm the 18 Sound 10CX650 reaches into the upper bass — the “Extended LF design” that 18 Sound highlights.
The ferrite motor positions the 18 Sound 10CX650 at a lower cost point than the neodymium coaxials. For installed sound applications — Atmos systems, distributed background music, conference sound, retail environments — where many speakers are needed and per-unit cost directly affects the system budget, ferrite’s lower material cost makes the 18 Sound 10CX650 more cost-effective to deploy at scale. The 6.2 kg weight is the trade-off — heavier than a neodymium equivalent would be, but for fixed installations where the speakers mount once and stay, weight is less critical than cost.
The comparison to the neodymium 12NCX750 illustrates the different design philosophies. The 12NCX750 is lighter (4.5 vs 6.2 kg), has higher LF sensitivity (97 vs 94 dB), uses neodymium, and has a titanium HF diaphragm. The 18 Sound 10CX650 has wider dispersion (90° vs 80°), the Atmos-ready PEN HF diaphragm, more flexible Qts, and lower cost from the ferrite motor. Different formats, different materials, different applications — both deliver coaxial point-source coherence.
Conclusion – 18 Sound 10CX650 Coaxial Driver
The 18 Sound 10CX650 is the most compact, widest-coverage coaxial in 18 Sound’s range. The 90° conical dispersion is unmatched by any other 18 Sound coaxial. The PEN HF diaphragm delivers smooth, natural, fatigue-free treble from a high-performance polymer that produces no metallic resonance. The Atmos-ready design confirms the 18 Sound 10CX650’s suitability for the immersive audio installations that are redefining professional installed sound.
The ferrite motor keeps cost accessible for multi-speaker installations where per-unit price defines the system budget. The 65 mm edgewound copper ISV LF coil provides the linear motor behaviour that 18 Sound’s ISV technology delivers across the range. The 3P tangerine phase plug, EWAL HF coil, copper sleeve, and proprietary treated Nomex former bring the same HF engineering standards found on the neodymium coaxials to the 10-inch ferrite format.
For Dolby Atmos ceiling speakers, distributed sound systems, compact stage monitors, wide-coverage installed sound, and any application where the widest coaxial dispersion from the smallest format with the smoothest polymer treble defines the specification, the 18 Sound 10CX650 is the 10-inch coaxial that fills every angle. Ninety degrees, point-source coherence, PEN polymer smoothness, Atmos ready — the compact coaxial built for the widest coverage from the smallest footprint.
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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.
