STM M28 Omni-Purpose Module

Injection-moulded all-purpose loudspeaker cabinet which fulfils the role of downfill, providing 90°/120° of horizontal dispersion and 0° to 15° splaying angle between modules. Same width as M46, 2/3 height, the M28 can also be used independently from M46 or B112 to create compact line array systems.

M28 features innovative CompassRigTM and REDLockTM rigging, enabling any size of system to be flown safely by one person. Compass RigTM allows pre-setting of inter-cabinet angle values. REDLockTM handle locks front rigging points from rear of cabinet. All adjustments made from one position at rear of cluster.

Key Features

  • 2 x 8 inch LF Drivers
  • 2 x HF Compression Driver
  • 141dB peak SPL
  • Frequency response: 65Hz-19kHz
  • H234mm/W575mm/D653mm
  • 37Kg/82lb


STM M28 with NXAMP 4x4
Frequency Response [a]65Hz – 19kHz ±3dB
Usable Range @-6dB [a]60Hz – 20kHz
Sensitivity 1W @ 1m [b]106dB SPL Nominal (120° horizontal coverage)
107dB SPL Nominal (90° horizontal coverage)
Nominal Peak SPL @ 1m [b]140dB Peak (120° horizontal coverage)
141dB Peak (90° horizontal coverage)
Dispersion [c]Configurable 90°-120° Horizontal x 0-15° vertical
Crossover Frequency900Hz (Active)
Nominal ImpedanceLF: 8 Ω (6 Ω min) - HF: 8 Ω (6 Ω min)
Amplified ControllerNXAMP4x4 - 3xSTM M28 in parallel on 2
NXAMP4x4 channels - 2x4000W/2Ω


Components :LF: 2 x 8" (20cm) high excursion 16 Ω
Neodymium drivers
HF: 2 x 2.5" voice coil, 1.4" throat Neodymium
Height x Width x Depth234 x 575 x 653 mm – 9.2” x 22.6” x 25.7”
Weight : Net 37kg – 82lbs
Connectors2 x NLT4-MDV Speakon 4 poles
ConstructionPU Composite Low Density – Polyurethane
water based black coating
Fittings:Handles: 3 handles (2 sides and 1 rear)
Front: Perforated Dark Grey Metal Grille
Rigging: Integral 3 points flying system.
Intercabinet angle adjustments from 0.2° to 15°
in logarithmic steps.


STM Brochure