21NTLW5000

PRELIMINARY
Extended Low Frequency Tetracoil Neodymium Transducer

Key Features

96,5 dB SPL 1W / 1m average sensitivity
Dual 115mm (4,5 in) Tetracoil Aluminum Voice coil
4000 W program power handling
Ultra linear suspension behavior for excellent sound clarity
Symmetric flux density and inductance behaviour
Low noise forced air cooling design
Water repellent cone and epoxy coated plates
Suitable for vented, horn loaded and bandpass applications
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Description

The 21NTLW5000 is a 21 inch diameter next generation high performance subwoofer, specifically designed for high SPL very low frequency applications in either a reflex, bandpass or horn loaded configuration. For optimum results we recommend the usage of power amplifiers able to deliver 4000W program power without clipping.

The 21NTLW5000 uses Eighteen Sound proprietary Tetracoil technology, where two different, axially separated magnetic gaps and two inside-outside 4.5" diameter aluminum voice coils are wound on the same former and suspended evenly in the two magnetic gaps.

The Tetracoil design key advantages are:
1) a symmetric flux density versus displacement behavior, that minimizes the even distortion products;
2) a very symmetric and flat inductance curve;
3) the equivalent voice coil diameter of a 4.6" Tetracoil speaker is greater than 6". Consequently heat dissipation occurs over a larger surface area, driving AES power handling up to 1800 W.

21NTLW5000 design features include a large displacement suspension system which, in conjunction with a fiberglass reinforced, straight ribbed cone allows an ultra-linear piston action and provides full mechanical control across the entire working range.

In order to furtherly increase power handling and reduce power compression figure, a low density material air diffractor is placed into the backplate venting hole acting as a cooling system, increasing power handling capability and lowering the power compression figure.

21NTLW5000 is able to perform properly under inclement weather conditions: the exclusive cone treatment improves pulp strength and gives water repellent properties to both sides of the membrane. In addition, magnetic structure metal plates coating is far more resistant than standard zinc coating to the corrosive effects of salts and oxidization.



General Specifications

Nominal Diameter 533 mm (21 in)
Rated Impedance 8 Ohm
AES Power 1800 W
Program Power 4000 W
Sensitivity 97 dB
Frequency Range 30-1800Hz
Max Recomm. Frequency 150 Hz
Recomm. Enclosure Volume 120 ÷ 250 lt. (4.24 ÷ 8.83 cu.ft)
Minimum Impedance 6.8 Ω at 25°
Max Peak To Peak Excursion 65 mm (2.56 in)
Voice Coil Diameter dual 115 mm (4.53 in)
Voice Coil winding material Aluminum
Suspension Triple roll, Polycotton
Cone Curvilinear paper composite, Water, UV repellent

Thiele Small Parameters

Fs 31 Hz
Re 5,3 Ohm
Sd 0.1662 sq.m (257.61 sq.in)
Qms 5.20
Qes 0.38
Qts 0.36
Vas 270 lt. (9.54 cu.ft)
Mms 372 gr. (0.82 lb)
BL 32 Tm
Linear Mathematical Xmax ±17.5 mm (±0.69 in)
Le (1kHz) 1.60 mH
Ref. Efficiency 1W@1m (half space) 2.1 %

Mounting information

Overall diameter 545 mm (21.46 in)
N. of mounting holes and bolt 8
Mounting holes diameter 8.5 mm (0.33 in)
Bolt circle diameter 520 mm (20.47 in)
Front mount baffle cutout ø 492 mm (19.37 in)
Rear mount baffle cutout ø 490 mm (19.29 in)
Total depth 320 mm (12.60 in)
Flange and gasket thickness 18 mm (0.71 in)
Net weight 12.5 kg (27.56 lb)
Packaging Dimensions 570x570x350 mm (22.44x22.44x13.78 in)

Models

Model Code Info
21TNLW5000 8 Ohm 022218N500

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