Key features:

linear cone excursion 60mm peak TO peak !!
unparallel low distortion at low frequencies
patented design, innovative magnetic structure & venting system

Design notes:

The 21XR is a high efficiency, (96 dB 1watt / 1 meter) 21-inch woofer with incredibly linear frequency response characteristics. Our new and patented ground up motor design is a new approach to high-excursion woofers. The voice coil winding is always in the magnetic gap that is extremely wide. This feature ensures extremely low distortion across whole working range of this unique driver. Motor DesignThe magnetic design incorporates large neodymium magnets placed along the voice coil winding. This has allowed us to push the cone excursion to 50mm peak to peak. Unique gap venting ensures good air circulation and greatly improves the reliability of this driver. We have also developed a new technique for manufacturing deep copper caps that are implemented in this design and covering the whole voice coil movement.. The design further utilizes triple, uncommonly large, spiders, spaced with spacers, hot-pressed tinsel wires onto the top spider, reinforced cone edge, reinforced surround to cone joint, reinforced spider to basket joints, etc.

Specifications:

General specs

Nominal Diameter: 21 in.

Rated Impedance: 8 Ohm

Power handling

AES Power: 1,800 Watts

Program Power: 3,600 Watts

Voice Coil

Diameter: 5.3 in.

Winding wire: Copper

Former: kapton

Winding height: 21 mm

T/S Parameters
Resonant frequency:	32.3 Hz
Re:	4.5 ohm
Qes:	0.51
Qms:	16.79
Qts:	0.5
Vas:	152.79 liters
Sd:	1,662 cm2
Mms:	488.58 grams
Bl:	29.37
Le:	0.65 mH
Sensitivity:	95.7 dB

Design details
Surround Material:	Fabric
Cone material:	Paper
Spider:	Nomex
Plate thickness:	66.66 mm
Peak to peak linear cone Displacement	n/a mm
Overall diameter:	549 mm
Bolt circle diameter:	525 mm
Baffle cutout dia.:	503 mm
Number of mounting holes:	8
Depth (flange to rear):	287 mm
Net weight:	23.8 kg

Categories

Spares - Driver 21"

21 SW 115

21 SW 152

21XR-X8