LF
Woofer
12"
121XR
Code: 121XRX8-352
XR Woofer/12inch/Neo/Paper/500W/8ohm
Key Features
- EXTENDED FREQUENCY RESPONSE, high excursion, ultra low THD
- Static demodulation coil, large spider with stitched tinsel wires
- Carbon fiber loaded paper cone
Quick Specs
Impedance
8 Ω
Program Power
1000 W
Sensitivity
95.78 dB
Fs
46.00 Hz
Magnet
Neodymium
Voice Coil
63.5 mm
Design Notes
The 121XR was designed to be simply the best driver for 2-way and multi-way systems on the market, yet this driver will also shine in sub-woofer applications. The combination of our XR patented technology with static shorting coil brings an nonparallel opportunity to the audio designers. The common request for 2-way speakers is “more of everything”. Designers wishes for more bass, more mids. Well, there you have it! But not only that. We bring this with clarity in the mid-frequencies and undistorted bass. Our designers were able to achieve THD below 0.5% from 20Hz up to 2.5kHz. There isn’t another driver like this on the market.
Motor Design
The magnetic design incorporates large neodymium magnets placed along the voice coil winding, together with the 2nd and static coil placed on the pole piece. This has allowed us to push the cone excursion to 25mm peak to peak, while lowering the inductance. The shorting coil covers the complete main coil excursion. This is also an improvement compared to some previous designs on the market. Unique gap venting ensures good air circulation and greatly improves the reliability of this driver.
Motor Design
The magnetic design incorporates large neodymium magnets placed along the voice coil winding, together with the 2nd and static coil placed on the pole piece. This has allowed us to push the cone excursion to 25mm peak to peak, while lowering the inductance. The shorting coil covers the complete main coil excursion. This is also an improvement compared to some previous designs on the market. Unique gap venting ensures good air circulation and greatly improves the reliability of this driver.
Specifications
General Specs
Nominal Diameter
12"
Rated Impedance
8 Ohm
Magnet
Neodymium
Basket Material
Aluminum
Power Handling
AES Power
500 W
Continuous Power
1000 W
Peak Power
2000 W
Voice Coil
Diameter
63.5 mm
Winding Wire
Copper
Former
Glass Fiber
Winding Height
18.3 mm
T/S Parameters
Resonant Frequency (Fs)
46.00 Hz
Re
5.60 \u2126
Qes
0.420
Qms
1.56
Qts
0.330
Vas
69.10 liters
Sd
531.00 cm\u00B2
Mms
66.80 grams
Rms
12.37
Cms
0.1800
Bl
16.00 T\u00B7m
Le
0.160 mH
Sensitivity
95.78 dB
Design Details
Surround Material
fabric
Cone/Dome Material
Paper CF
Spider
Nomex
T-Plate
31 mm
Xmax (peak)
6.35 mm
Xmech
29.85 mm
Overall Diameter
320.00 mm
Bolt Circle Diameter
299.00 mm
Baffle Cutout Dia.
281.00 mm
Mounting Holes
8
Depth (flange to rear)
172.50 mm
Net Weight
5.10 kg
Ordering Codes
Product Code
121XRX8-352
Downloads
Frequency Response & Impedance
2D Drawing
Technical Summary
This design is particularly effective in single or multi-driver bass reflex systems used in professional two-way and multi-way PA systems, powered monitors, and compact bass-reflex enclosures, where extended bandwidth, controlled distortion across the full operating range, and versatile system integration are required.
Enclosure Recommendations
ENCLOSURE RECOMMENDATIONS: 121XRX8-352
Driver: 121XRX8-352 (121XR) — 12" Mid-Woofer
Key T/S: Fs=46.0Hz, Qts=0.33, Vas=69.1L, Sens=95.78dB
Power: AES 500W / Cont 1000W / Peak 2000W
Xmax=6.35mm, Sd=531.0cm², Bl=16.0T·m
RECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)
PORT RECOMMENDATION: Round port (100mm diameter) — standard for mid-size professional enclosures; good balance of area and packaging
a) High SPL
Net Volume: 55 liters
Tuning (Fb): 51 Hz
Est. -3dB: 47 Hz
HP Filter: 43 Hz (24dB/oct recommended)
Round Port: 100mm dia × 84mm long
Slot Port: 225mm W × 60mm H × 174mm L
Port Velocity: 13.7 m/s
Notes: Strong mid-bass impact, reduced cone excursion, maximum output
b) Balanced Response
Net Volume: 65 liters
Tuning (Fb): 45 Hz
Est. -3dB: 38 Hz
HP Filter: 35 Hz (24dB/oct recommended)
Round Port: 100mm dia × 101mm long
Slot Port: 225mm W × 60mm H × 203mm L
Port Velocity: 12.0 m/s
Notes: General-purpose PA/subwoofer, even response, good transient behavior
c) Extended Low Frequency
Net Volume: 80 liters
Tuning (Fb): 39 Hz
Est. -3dB: 33 Hz
HP Filter: 27 Hz (24dB/oct recommended)
Round Port: 100mm dia × 121mm long
Slot Port: 225mm W × 60mm H × 238mm L
Port Velocity: 10.5 m/s
Notes: Deep bass extension, requires proper system protection below tuning
--- Summary ---
The 121XRX8-352 is a 12-inch mid-woofer driver designed for professional 2-way and multi-way systems requiring high sensitivity (96 dB 1W/1m) and controlled low-frequency behavior. The motor and suspension are optimized to maintain consistent performance at high drive levels, with controlled excursion and reduced thermal compression during long-term operation.
In bass reflex enclosures, the driver performs best in net internal volumes of 55 to 80 liters, tuned between 39 and 51 Hz. This alignment provides a balanced combination of low-frequency extension, cone control around resonance, and efficient port loading. Lower tuning improves deep bass extension but increases excursion below tuning, requiring appropriate high-pass filtering. Higher tuning increases sensitivity and output in the upper bass region while improving mechanical control.
The driver is intended for use with high-power amplification (approx. 500 W AES / 1000 W continuous) and DSP control. A high-pass filter in the range of 27–43 Hz is recommended depending on enclosure tuning, along with proper limiting to manage thermal and mechanical stress. Typical operating bandwidth is 33–2000 Hz, covering bass through upper-mid frequencies for direct integration with a compression driver or tweeter in a two-way or multi-way system.
Frequently Asked Questions
- - EXTENDED FREQUENCY RESPONSE, high excursion, ultra low THD
- - Static demodulation coil, large spider with stitched tinsel wires
- - Carbon fiber loaded paper cone
ENCLOSURE RECOMMENDATIONS: 121XRX8-352
Driver: 121XRX8-352 (121XR) — 12" Mid-Woofer
Key T/S: Fs=46.0Hz, Qts=0.33, Vas=69.1L, Sens=95.78dB
Power: AES 500W / Cont 1000W / Peak 2000W
Xmax=6.35mm, Sd=531.0cm², Bl=16.0T·m
RECOMMENDED ENCLOSURE TYPE: Bass Reflex (Vented)
PORT RECOMMENDATION: Round port (100mm diameter) — standard for mid-size professional enclosures; good balance of area and packaging
a) High SPL
Net Volume: 55 liters
Tuning (Fb): 51 Hz
Est. -3dB: 47 Hz
HP Filter: 43 Hz (24dB/oct recommended)
Round Port: 100mm dia × 84mm long
Slot Port: 225mm W × 60mm H × 174mm L
Port Velocity: 13.7 m/s
Notes: Strong mid-bass impact, reduced cone excursion, maximum output
b) Balanced Response
Net Volume: 65 liters
Tuning (Fb): 45 Hz
Est. -3dB: 38 Hz
HP Filter: 35 Hz (24dB/oct recommended)
Round Port: 100mm dia × 101mm long
Slot Port: 225mm W × 60mm H × 203mm L
Port Velocity: 12.0 m/s
Notes: General-purpose PA/subwoofer, even response, good transient behavior
c) Extended Low Frequency
Net Volume: 80 liters
Tuning (Fb): 39 Hz
Est. -3dB: 33 Hz
HP Filter: 27 Hz (24dB/oct recommended)
Round Port: 100mm dia × 121mm long
Slot Port: 225mm W × 60mm H × 238mm L
Port Velocity: 10.5 m/s
Notes: Deep bass extension, requires proper system protection below tuning
--- Summary ---
The 121XRX8-352 is a 12-inch mid-woofer driver designed for professional 2-way and multi-way sy...
This design is particularly effective in single or multi-driver bass reflex systems used in professional two-way and multi-way PA systems, powered monitors, and compact bass-reflex enclosures, where extended bandwidth, controlled distortion across the full operating range, and versatile system integration are required.
AES Power: 500 W,
Continuous: 1000 W,
Peak: 2000 W.
Sensitivity: 95.78 dB (1W/1m).
