18SOUND 12NCX750
18SOUND (Eighteen Sound) 12NCX750 — 12" / 12 inch Coaxial Driver · Coax / Coaxial Driver · Neodymium
3"/2.4" voice coils · 8 Ω
Part no.: 42A-CHS-KO-18S-0008
Documents
18SOUND 12NCX750 — 12" · Coaxial Driver
400 W AES · 97 dB Sensitivity · Frequency range 60 Hz – 5000 Hz
Technical data
- Diameter: 12 "
- Voice coil: 3 "
- Power handling: 400 W AES
- Sensitivity: 97 dB
- Impedance: 8 Ω
- Magnet: Neodymium
- Weight: 4.5 kg
- Mounting depth: 148 mm
- Frequency range: 60 – 5000 Hz
- Cone material: Titanium
- Coverage angle: 80 °
- Rec. crossover: 1.2 kHz
Datasheet (PDF) · Manufacturer page
Series: NCX · Part no.: 42A-CHS-KO-18S-0008
18Sound 12NCX750: 12" coaxial driver with 400 W AES, 97 dB and 80° horn
The 18Sound 12NCX750 is the 12" version of the NCX coaxial range: a woofer with a 3" voice coil, in whose centre a compression driver with a 2.4" voice coil and titanium diaphragm works through a conical horn with 80° dispersion. A neodymium motor, 4.5 kg and 148 mm mounting depth make it one of the lighter 12" coaxes in this power class – 400 W AES power handling and 97 dB sensitivity at 8 Ω.
Compared with the smaller NCX model, the larger cone with Sd 531 cm² brings more area for the low end and a lower resonance of 58 Hz. The parameters Qts 0.29, Vas 63 l, BL 17.5 Tm and Mms 48 g describe a tightly controlled motor that wants to work in a bass reflex enclosure; the Le of 0.62 mH is moderate for a 3" coil and helps the response up to the crossover. The Xmax of 5.5 mm is sufficient for a top, not intended for deep bass without a subwoofer.
Use and enclosure
A 12" coax is the classic heart of a stage monitor and of compact full-range tops: one source, the same dispersion across the whole transition, no vertical interference between two separate drivers. The same applies to installations with limited front height or to active studio monitors with high level demands. From the Thiele-Small parameters, the bass reflex guide value is around 27 l net tuned to 74 Hz with an f3 near 85 Hz – a manageable volume for a top with noticeable punch. The EBP of 187 shows that a sealed box would deliver little extension; the guide value of 13 l at fc 141 Hz is of interest only as a mid-high compartment above a sub. The exact alignment is a job for the enclosure calculator at 42.audio.
18Sound recommends the crossover between woofer and HF horn at 1.2 kHz. At this point the 12" cone is already beaming noticeably, and the 80° horn takes over with matching coverage – that is why the coaxial format works so cleanly here. Active with DSP and delay correction this is set up quickly; passively it pays to measure both ways in the cabinet before building the network.
What to look out for
- 400 W AES at 8 Ω, 97 dB sensitivity – size the amplifier accordingly
- Bass reflex guide 27 l, tuning 74 Hz; EBP 187 argues against sealed
- Neodymium, only 4.5 kg at 148 mm mounting depth
- Recommended crossover 1.2 kHz between 12" cone and 80° horn
- Xmax 5.5 mm: top or monitor, deep bass via subwoofer
Frequently asked questions
What distinguishes the 12NCX750 from the 12NCX910?
The 12NCX910 has a 3" voice coil in the HF section instead of 2.4", is similarly aligned in the woofer section at fs 57 Hz, Qts 0.3 and Vas 58 l, but is considerably heavier and deeper. The 12NCX750 is the lighter, more compact variant at 148 mm mounting depth.
And the difference to the 12NCX750H?
The same woofer and driver, but an asymmetric horn instead of the conical 80° dispersion. The Thiele-Small parameters are identical at fs 58 Hz, Qts 0.29 and Vas 63 l, so the enclosure design is the same.
Can I use the driver in a monitor wedge of just under 27 l?
Yes, that is exactly the range the bass reflex guide value stands for. In the wedge make sure the port area is sufficient so that no chuffing occurs at 400 W AES, and cross at 1.2 kHz with delay alignment if you run it actively.
18Sound 12NCX750: 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 12NCX750 is a 12-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 12NCX750 with datasheet PDF, all key data in the driver database and the enclosure calculator. More drivers from this manufacturer: Atlas 18Sound.
Thiele-Small parameters
| Nominal impedance | 8 Ω |
|---|---|
| Resonance frequency fs | 58 Hz |
| Total Q Qts | 0.29 |
| Electrical Q Qes | 0.31 |
| Mechanical Q Qms | 6.42 |
| Equivalent volume Vas | 63.0 l |
| Moving mass Mms | 48.0 g |
| Cone area Sd | 531 cm² |
| Linear excursion Xmax | 5.5 mm |
| Force factor BL | 17.5 Tm |
| DC resistance Re | 5.4 Ω |
| Voice coil inductance Le | 0.62 mH |
Enclosure suggestion
The EBP of 187 suggests a bass-reflex enclosure. EBP = fs / Qes = 58 / 0.31
Sealed (Qtc 0.707)
- Enclosure volume Vb
- 12.7 l
- System resonance Fc
- 141 Hz
- Cut-off frequency F3
- 141 Hz
Bass reflex (QB3 after Small)recommended
- Enclosure volume Vb
- 21.2 l
- Tuning frequency Fb
- 81 Hz
- Cut-off frequency F3
- 94 Hz
Vb is the required net internal volume, Fb the tuning frequency of the reflex port and F3 the frequency at which the level has dropped by 3 dB. Calculated approximation after Small. A starting point for simulation, not a finished build plan.
Comparable drivers
Same size, same type, Qts within ±30 %.
- 18 Sound 12NCX750Hfs 58 Hz · Qts 0.29 · Vas 63 l · in the shop
- 18 Sound 12NCX910fs 57 Hz · Qts 0.3 · Vas 58 l · in the shop
- 18 Sound 12NCX910BEfs 57 Hz · Qts 0.3 · Vas 58 l · in the database
- 18 Sound 12NCX910Nfs 57 Hz · Qts 0.3 · Vas 58 l · in the shop
- B&C Speakers 12FHX76fs 48 Hz · Qts 0.33 · Vas 88 l · in the database
- Beyma 12CXA400Ndfs 45 Hz · Qts 0.25 · Vas 88.5 l · in the shop
Specifications
| Allgemein | |
|---|---|
| Manufacturer | 18SOUND |
| Category | Coaxial |
| Series | NCX |
| Magnet | Neodymium |
| Impedance (Ω) | 8 |
| Power handling (W) | 400 |
| Sensitivity (dB) | 97 |
| Frequency from (Hz) | 60 |
| Frequency to (Hz) | 5000 |
| Abmessungen & Korb | |
|---|---|
| Diameter | 12 |
| Voice coil (inch) | 3 |
| Mounting depth (mm) | 148 |
| Weight (kg) | 4.5 |
| Thiele-Small-Parameter | |
|---|---|
| Re (Ω) | 5.4 |
| Le (mH) | 0.62 |
| Fs (Hz) | 58 |
| Qms | 6.42 |
| Qes | 0.31 |
| Qts | 0.29 |
| Vas (l) | 63 |
| Xmax (mm) | 5.5 |
| BL (Tm) | 17.5 |
| Mms (kg) | 0.048 |
| Sd (m²) | 0.0531 |