The JBL 122A is a 12-inch (305mm) cone-type woofer featuring an Alnico V magnet structure, edgewound aluminum ribbon voice coil, and JBL's proprietary cone treatment. An evolution of the earlier L65 woofer design, the 122A incorporates a mass control ring for enhanced low-frequency performance and improved transient response. Used in the L166 Horizon, it represents a refinement of JBL's 12" woofer engineering.
| Nominal Diameter | 12" (305mm / 30cm) |
|---|---|
| Magnet Type | Alnico V (Aluminum-Nickel-Cobalt) |
| Voice Coil Diameter | 3" (75mm) |
| Voice Coil Material | Edgewound aluminum ribbon |
| Cone Material | Paper with proprietary coating |
| Surround | Accordion fabric |
| Frame | Cast aluminum |
| Nominal Impedance | 8 Ω |
| Power Handling | 75W continuous |
| Frequency Response | 40 Hz - 2.5 kHz |
| Sensitivity | 89 dB / 2.83V / 1m |
| Cone Mass | Approximately 100 grams |
| Weight | Approximately 7.5 kg |
| Mounting Depth | Approximately 135mm |
| Cutout Diameter | 283mm (11.125") |
| Bolt Circle Diameter | 297mm (11.7") |
Mass Control Ring: A die-cast aluminum ring mounted on the back of the center dome extends the playback band smoothly to the lower range while preventing deformation of the voice coil and cone. This innovation improves power handling and reduces distortion.
Alnico V Magnet: Premium aluminum-nickel-cobalt magnet provides exceptional transient response, flux stability, and resistance to demagnetization.
Edgewound Voice Coil: The 3-inch diameter voice coil uses aluminum ribbon wire wound on edge, maximizing conductor density in the magnetic gap for improved heat dissipation and reduced compression.
Accordion Surround: Fabric surround with accordion pleats provides controlled compliance and excellent long-term durability.
Cast Aluminum Frame: Rigid die-cast frame construction minimizes resonances and provides stable mounting.
122A: Original version (1975-1978)
122A-1: Later production revision with minor improvements (1978-1980)
The 122A was an evolution of the woofer used in JBL's L65 Jubal. The key improvement was the addition of the mass control ring, which helped extend low-frequency response while maintaining the dynamic, uncompressed character that JBL woofers were known for.
The L166 Horizon, which featured the 122A alongside the groundbreaking 066 dome tweeter, represented JBL's transition from the "West Coast Sound" era to more refined, neutral reproduction while maintaining high efficiency and dynamic range.
123A: Similar 12" woofer used in L100 Century, without mass control ring
128H: Ferrite magnet successor with SFG magnetic circuit
2213H: Professional version with similar performance characteristics
The accordion fabric surround on the 122A is generally very durable, but after 40+ years may require inspection for deterioration. Correct cone mass (approximately 100g) is critical for proper performance. The Alnico magnet structure should be protected from physical shock. Replacement cones and refoam kits are available from specialty suppliers.