• S721300
  • DE 29323089


A cone midrange driver in an elegant design, trimmed for maximum sound quality – and thus the perfect addition to any fully active 3-way speaker system.

The highly rigid membrane consists of a novel basalt fiber-paper compound. An ideal combination to ensure clear and precise sound even at high volumes  In addition to maximum uncoloured mid-range reproduction, the S 3M also offers extremely low distortion thanks to the linear neodymium magnet system.

The dream team is the combination with the S 1T tweeter and a S 6B or S 4B woofer. Driven by a power amplifier from Audiotec Fischer, the S loudspeakers perform at their best and provide the perfect basis for absolute top sound systems!


  • 3” / 75 mm cone midrange speaker with novel basaltfiberpaper compound cone – a perfect combination of lowest weight, high stiffness and perfect inner damping
  • Highly efficient, compact neodymium magnet system for linear drive and minimum distortion
  • Low-resonant basket made from glassfiber reinforced plastic with optimized voice coil cooling for high power handling
  • Grille included

Technical data

Power RMS / max.


75 / 150 Watts
(highpass > 400 Hz at 24 dB/Oct.)
Impedance  Z 4 Ω
DC resistance  Re 3.2 Ω
Frequency response   400 Hz - 6,000 Hz
Resonance frequency  Fs 130 Hz
Mechanical Q factor  Qms 4.47
Electrical Q factor  Qes 0.48
Total Q factor Qts 0.43
Compliance Cms 396 µm/N
Equivalent air volume Vas 0.57 L
Force factor  B*I 4.6 Tm
Sensitivity 1 W / 1 m SPL 86 dB
Cone area  Sd 32 cm²
Moving mass  Mms 3.8 g
Cone material   Basalt-fiber-paper compound
Mechanical resistance  Rms 0.69 kg/s
Voice coil diameter ø 25 mm
Voice coil winding height   8 mm
Max. linear excursion  Xmax +/- 2 mm
Outer diameter ø 90 mm / 3.54"
Installation diameter ø 73 mm / 2.87"
Installation depth   37 mm / 1.46"
Recommended enclosure volumes    
Sealed box with minimum 200 ml net volume    
Net volumes   Recommended DSP / amplifier settings
0.2 liter (System resonance: 230 Hz)   Crossover frequency: 500 Hz
Min. filter slope: 12 dB/Oct.
0.4 liter (System resonance: 190 Hz)   Crossover frequency: 450 Hz
Min. filter slope: 18 dB/Oct.
0.6 liter (System resonance: 170 Hz)   Crossover frequency: 400 Hz
Min. filter slope: 24 dB/Oct.

Note: The enclosure should always be filled with appropriate damping material.

Scope of delivery

2 x Midrange speaker HELIX S 3M
2 x Grille
1 x Data sheet
1 x Mounting pattern

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