240 12NDA520 - LF Transducers
12NDA520
Neodymium LF-MB-MF Transducer
KeyFeatures
100,5 dB SPL 1W / 1m average sensitivity
65 mm (2,52 in) Interleaved Sandwich Voice coil (ISV)
300W AES power handling
Neodymium magnet assembly
AIC (Active Impedance Control) secondary voice coil for superior intelligibility, very low distortion
and inductance linearization
Suitable for two way high quality applications
Description
The 12NDA520 is a 12" mid-low transducer created for compact reflex 2-way enclosures and
designed to be coupled with typical 1" and 1.4" compression drivers. It can also be used in midlow applications on modern line-array systems. Its features and design characteristics make it
extremely defined in mid-range frequencies and offer a significant and consistent bottom-end,
making the product also suitable for monitoring applications. The 12NDA520 incorporates our
proprietary Active Impedance Control technology (AIC), consisting of an additional coil fixed on
the pole piece and connected in parallel to the moving coil. The magnetic field generated by this
coil has the following effects: 1) Impedance linearization 2) Acoustic and electric phase
linearization 3) Significant increase of sensitivity and total SPL 4) Total harmonic distortion
reduction 5) Constant power transfer By not absorbing the moving coil's electromagnetic
energy, AIC offers substantial advantages relating to the quality of sound. The neodymium
magnet assembly developed by Eighteen Sound engineers assures high flux concentration, low
power compression and excellent heat exchange since the external magnet configuration is
considerably more efficient than traditional under-pole magnet topology. This results in high
levels of force factor and power handling with an optimum power to weight ratio. The curvilinear
cone, created from a high damping wood pulp, has been designed to achieve the best possible
linearity within its intended frequency range. The 12NDA520 employs our Interleaved Sandwich
Voice coil (ISV) technology in which a high strength fiberglas former carries windings on both the
outer and inner surfaces to achieve a mass balanced coil. The final result is an extremely linear
motor assembly with a reduced tendency for eccentric behavior when driven hard. A proprietary
humidity-block cone treatment makes the transducer suitable for outdoor use in adverse
weather conditions. In addition, a special coating applied to both the top and back plates makes
the 12NDA520 far more resistant to the corrosive effects of salts and oxidization.
Models
Model
12NDA520
Code
12NDA520
Information
12NDA520
Neodymium LF-MB-MF Transducer
General Specifications
Nominal Diameter
Rated Impedance
AES Power
Program Power
Peak Power
Sensitivity
Frequency Range
Power Compression @-10dB
Power Compression @-3dB
Power Compression @Full Power
Max Recomm. Frequency
Recomm. Enclosure Volume
Minimum Impedance
Max Peak To Peak Excursion
Voice Coil Diameter
Voice Coil Winding Material
Suspension
Cone
300mm (12 in)
8 Ohm
300W
450W
900W
100,5dB
55 - 6000 Hz
0,7 dB
2,5 dB
3,9 dB
2000 Hz
35 ÷ 80 lt. (12 ÷ 28 cuft)
6,5 Ohm at 25°C
22 mm (0,87 in)
65 mm (2,5 in)
aluminum
Triple roll, polycotton
curvilinear, paper
FREQUENCY RESPONSE CURVE OF 12NDA520 MADE ON 50 LIT. ENCLOSURE TUNED 60HZ
INFREE FIELD (4PI) ENVIRONMENT. ENCLOSURE CLOSES THE REAR OF THE DRIVER. THE
THIN LINE REPRESENTS 45 DEG. OFF AXIS FREQUENCY RESPONSE
Thiele Small Parameters
Fs
Re
Sd
Qms
Qes
Qts
Vas
Mms
BL
Linear Mathematical Xmax
Le (1kHz)
Ref. Efficiency 1W@1m (half space)
50 Hz
5,2 Ohm
0,0531 sq.mt. (82,31 sq.in.)
5,5
0,284
0,27
111 lt. (3,9 cuft)
36 gr. (0,08 lb)
14,4 Tm
± 4 mm (±0,16 in)
0,03 mH (AIC on) - 0,57mH (AIC off)
98,9 dB
FREE AIR IMPEDANCE MAGNITUDE CURVE - AIC ON
Notes
1) AES power is determined according to AES2-1984 (r2003) standard
Mounting information
Overall diameter
N. of mounting holes and bolt
Mounting holes diameter
Bolt circle diameter
Front mount baffle cutout ø
Rear mount baffle cutout ø
Total depth
Flange and gasket thickness
Net weight
Shipping weight
CardBoard Packaging dimensions
315 mm (12,4 in)
8
7,15 mm (0,28 in)
296-300 mm (11,65-11,8 in)
282 mm (11,1 in)
282 mm (11,1 in)
125 mm (4,92 in)
11,5 mm (0,45 in)
2,2 kg (4,86 lb)
3 kg (6,62 lb)
332 x 332 x 184mm (13,07 x 13,07 x 7,24 in)
2) Program power rating is measured in a 50 lit enclosure tuned at 60Hz, using a 60 -2000 Hz
band limited pink noise test signal with 50% duty cycle, applied for 2 hours.
3) The peak power rating represents the maximum permitted instantaneous peak power level
over a maximum period of 10ms which will be withstood by the loudspeaker without damage.
4) Sensitivity represents the averaged value of acoustic output as measured on the forward
central axis of cone, at distance 1m from the baffle panel, when connected to 2,83V sine wave
test signal swept between 100Hz and 500Hz with the test specimen mounted in the same
enclosure as given for (1) above.
5) Frequency range is given as the band of frequencies delineated by the lower and upper limits
where the output level drops by 10 dB below the rated sensitivity in half space environment.
6) Power compression represents the loss of sensitivity for the specified power, measured from
50-500 Hz, after a 5 min pink noise preconditioning test at the specified power.
7) Linear Math. Xmax is calculated as (Hvc-Hg)/2 + Hg/4 where Hvc is the coil depth and Hg is the
gap depth.
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