18SOUND ND32SA

18Sound ND32SA: 2" compression driver, aluminium dome, 3" coil, 8 or 16 Ω

The 18Sound ND32SA is the S version of the ND32A: a 2" compression driver from the ND series with aluminium diaphragm, 3" voice coil and neodymium magnet, available in 8 or 16 Ω. It targets two-way tops with a large woofer and three-way systems where a 2" driver is to handle the treble with plenty of thermal reserve.

The character is defined by the aluminium dome. Aluminium is below titanium in stiffness but damps better, so the diaphragm resonances turn out broader and lower in Q. In practice this means a presence region that is satisfied with less equalisation and a midrange that does not push forward with speech and vocals. The 3" coil is the prerequisite for high continuous levels because it absorbs and dissipates heat better than smaller coils; the neodymium motor keeps the driver's weight within limits despite the large magnet system.

Use and enclosure

As a 2" driver the ND32SA needs a 2" horn, at 18Sound one of the 2" models from the horns category. Further coverage patterns can be compared in the manufacturer's horns and waveguides category. A large horn with sufficient mouth area is the prerequisite for keeping directivity in the midrange and for crossing the driver low enough to noticeably relieve the woofer.

The high-pass should be steep, active 24 dB/octave, passive at least 12 dB/octave with a somewhat higher corner, always with a limiter on the HF branch. The lower limit depends on the horn; when in doubt cross a little higher. On the low side, large woofers in two-way tops or a midrange unit in three-way systems come into question. The efficiency of a 2" neodymium driver is far above that of a woofer, so attenuation via DSP gain or an L-pad belongs in every plan. If two drivers are to run on one channel, the 16 Ω version is the right one.

What to look out for

• 8 or 16 Ω: choose the impedance to suit the amplifier configuration, 16 Ω for two drivers per channel.
• Aluminium diaphragm: good damping, relaxed presence region, less EQ needed than titanium.
• 3" voice coil: high continuous power handling thanks to large thermal capacity.
• Neodymium magnet: low weight for the 2" class, suitable for flown use.
• Choose a 2" horn with a large mouth, use a steep high-pass and a limiter.

Frequently asked questions

18Sound ND32SA: 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 ND32SA is a compression driver with neodymium magnet from the ND 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 ND32SA with all key data in the driver database. More drivers from this manufacturer: Atlas 18Sound.