18SOUND 8NCX750N

18Sound 8NCX750N: 8" neodymium coax with NSD HF diaphragm and 3"/2.4" voice coils

The 8NCX750N is the NSD variant of the 8" coaxial driver 8NCX750 from 18Sound's NCX series. The basic construction stays: a neodymium motor, a 3" voice coil in the cone and a 2.4" voice coil in the tweeter, 8 Ω nominal impedance. The difference lies in the HF diaphragm, for which 18Sound uses the NSD version here instead of the titanium diaphragm of the base model.

Why that matters: in a coax, cone and tweeter share one axis, and the cone acts as a horn extension for the tweeter. The tweeter diaphragm therefore defines how the range above the crossover sounds and how resonances in the upper region behave. The mechanics of the 8" cone, the neodymium magnet structure and the mounting situation are interchangeable with the 8NCX750. If you have built an existing design around the 8NCX750, you can evaluate the 8NCX750N as an alternative with a different HF character without changing the cabinet.

Use and enclosure

Like the base model, the 8NCX750N is a mid-high coax for 3-way systems, not a full-range driver. That means a sealed midrange chamber, well damped, mechanically rigid, without a reflex port. Below, a separate woofer takes over, and you set that crossover with steep filters and a high-pass that protects the cone from low-frequency content. The upper crossover to the tweeter can be active or passive, and the 2.4" HF coil brings reserves for a low coupling point.

The target applications are the same as for the 8NCX750: compact point-source tops, studio monitors with coaxial mid-high and centre speakers in home theatres where the voice range should come from a single axis. The conical dispersion of the base model is not recorded as an attribute for the N version, so check 18Sound's documentation and the driver database at 42.audio before fixing the dispersion in your cabinet. Complete Thiele-Small parameters are currently not recorded as attributes for this variant at 42.audio; for the midrange chamber you can orient yourself on the values of the 8NCX750 and cross-check with the enclosure calculator.

What to look out for

• NSD HF diaphragm: the difference from the 8NCX750 with titanium diaphragm
• 8 Ω nominal: uncritical for any amplifier, check the manufacturer's power rating
• Midrange for 3-way: sealed, damped chamber, no bass reflex
• 3" cone coil and 2.4" HF coil: robust thermal behaviour at high levels

Frequently asked questions

18Sound 8NCX750N: manufacturer, spellings and classification

18Sound, 18 Sound and Eighteensound all refer to the same manufacturer: Eighteen Sound S.r.l. of Reggio Emilia, Italy. The 8NCX750N is a 8-inch coaxial driver with neodymium magnet from the NCX series, available from 42.audio, 18Sound dealer in Germany, with datasheet and full specifications in the driver database.

At 42.audio you get the 18SOUND 8NCX750N with all key data in the driver database and the enclosure calculator. More drivers from this manufacturer: Atlas 18Sound.