18SOUND XO 12 NCX 750
18SOUND (Eighteen Sound) XO 12 NCX 750 — Passive Crossover
für 12NCX750
Part no.: 42A-CHS-FW-18S-0003
Documents
18SOUND XO 12 NCX 750 — Crossover
400 W AES
Technical data
- Power handling: 400 W AES
- Impedance: 8 Ω
Datasheet (PDF) · Manufacturer page
Series: XO · Part no.: 42A-CHS-FW-18S-0003
18Sound XO 12 NCX 750: passive crossover matched to the 12NCX750 coaxial
The XO 12 NCX 750 is the passive crossover 18Sound designed specifically for its 12" coaxial driver 12NCX750. A coaxial puts a low-frequency cone and a compression driver on one axis, and those two sections have to be separated cleanly by the network, otherwise cone and horn section overlap in the critical region around the crossover point. Instead of adapting a generic crossover by trial and error, you get a circuit tailored to the impedance curve, level difference and phase behaviour of this one driver.
To put the driver in context: the 12NCX750 uses a neodymium motor, a 3" voice coil in the LF section, 400 W AES power handling and 97 dB sensitivity at 8 Ω. Its usable range runs from 60 Hz to 5,000 Hz, the HF section carries a titanium diaphragm and covers 80° of dispersion. The recommended crossover point is 1.2 kHz, and that is where the XO network places its filters.
Use and enclosure
The typical application is a passive two-way coaxial stage monitor or a compact full-range cabinet driven by a single amplifier channel: amp into the crossover, crossover into both sections of the 12NCX750, done. That is convenient for stage monitors, fixed installations and small PA systems because you skip the DSP, the second amp channel and the alignment work. Besides splitting the signal, the crossover handles level matching, since a compression driver on a horn is considerably louder than the cone and has to be padded down to its level.
The cabinet the coaxial needs is not decided by the crossover but by its parameter set: Fs 58 Hz, Qts 0.29, Vas 63 l and Xmax 5.5 mm. Run those numbers through the enclosure calculator at 42.audio, the complete data set is in the datasheet PDF and in the driver database. The crossover board itself belongs inside the cabinet, protected and preferably out of the direct airflow of a reflex port.
What to look out for
- Designed for the 12NCX750 only: level and impedance matching will be off on other drivers.
- 8 Ω system impedance of the coaxial, any common PA amplifier handles that.
- The 12NCX750 is rated 400 W AES, size the amplifier accordingly and do not treat the crossover as a fuse.
- Coaxial mounting depth 148 mm at 4.5 kg, allow room for driver and crossover board inside the box.
- Datasheet PDF and manufacturer page are linked directly on the product at 42.audio.
Frequently asked questions
Does the XO 12 NCX 750 also fit the stronger 12" coaxial of the NCX series?
No. The sibling model has a different sensitivity and a different recommended crossover point, and 18Sound offers a separate XO network for it. Level matching between cone and HF section would be wrong with the other crossover.
Which amplifier do I need for coaxial plus crossover?
One channel per cabinet at 8 Ω. Base the power on the 400 W AES rating of the 12NCX750, an amplifier in that range with some headroom for transients makes sense. A limiter protects cone and compression driver from clipping.
Do I still need a DSP?
Not for passive operation, the crossover splits at around 1.2 kHz and aligns the levels. A DSP ahead of the amplifier can still be useful for room correction or limiting. If you run the coaxial actively on two channels, the crossover is not needed at all.
At 42.audio you get the 18SOUND XO 12 NCX 750 with datasheet PDF, all key data in the driver database. More drivers from this manufacturer: Atlas 18Sound.
Specifications
| Manufacturer | 18SOUND |
| Category | Crossover |
| Series | XO |
| Impedance (Ω) | 8 |
| Power handling (W) | 400 |