Loudspeaker Project Example n 1 A Simple Compact Subwoofer Concept for M-Force 2015 Powersoft powersoft_mforce_kit_en_v1.1 Keep This Manual For Future Reference
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M-Force is an innovative and unique transducer based on a patented moving magnet linear motor structure. The M-Force motor is the result of years of FEM magnetic and mechanical simulations, careful integration of the latest magnetic materials, digital signal processing, acoustic design and power electronic conversion. The M-Force is a true paradigm shift from the old and fashionable coil and cone. Unlike conventional loudspeaker M-Force s moving magnet motor is a genuine push-pull engine where magnetic fields interactions guarantee linearity in power requirement versus moving element displacement. This, coupled to the the fact that no electical conductors are present in the motor s moving parts, brings forth high efficiency of the transducer: the moving magnet linear motor ensure a high force factor yielding negligible power compression and very low input impedance. With respect to conventional loudspeakers, M-Force drives less power from the amplifier to reach high audio performances, high SPL and low distortion. Loudspeaker Project Example n 1 A Simple Compact Subwoofer Concept for M-Force This simple design example will point up an application for exploiting the M-Force transducer. Some additional construction details are introduced to make this design useful and interesting for being implemented into further applications. This project aims to achieve a high output power subwoofer exploiting the M-Force technology motor transducer and a the 30 polymer cone. Specifically desined to drive the M-Force, the Powersoft SUB-Drive amplifier module can be implemented combining active control of the cone movement and performance enhancing thanks to the Powersoft s DPC Differential Pressure Control tool. Alternatively the M-Force transducer can be driven K10 DSP or K20 DSP amplifiers for passive applications. 33Very high power and energy efficient Subwoofer 33Low distortion high SPL applications 33Steerable low frequency arrays 33Low frequency noise and standing waves active removal systems 33Dipole low frequency acoustic generation 33Moving floors 33Acoustical stress testing devices 33Mechanical to electrical conversion applications 33Vibrational energy harvesting 33Structural active damping control 3
126,5 ± 0,5 110,5 ± 0,5 279 266 236 100 100 25 25 30 100 33Extremely low distortion levels ffzero Power Compression. ffvery Easy to match with different radiating surfaces / shapes. 33Very easy to combine in large arrays to create wall diaphragms ffdual Diaphragm / Push-Pull capability (for multi-resonator acoustical loads / multi-horn load). ffdifferent transducer to cabinet combination concept. 33Extremely reliable and efficient ffno service needed for years of abuse. ffage - Usage independent Magnetic Compliance. ffextremely insensitive to forces acting outside displacement axis (rocking). ffunique performances in terms of reliability. ffextreme performance in terms of overall efficiency. 33Extremely High SPL performances ffmore than 3 times output SPL capability for the same driver weight with respect to any other conventional design. 33Robust ffno moving conductors in the active part of the transducer. ffno electrical connection with moving parts and stationary parts ffpremium Motor Strength (exceeding 2200 (T m) 2 / ) ffoutstanding Acceleration Performances : up to 3800 m/s 2 (390 g) 33Environmental Friendly ff1/20 of Neodymium usage for the same SPL in comparison to conventional design. 4
24 Ø 7,5 30,5 243,5 Ø 764 Ø 732 Ø 7,5 22,5 Ø 764 Ø 732 30,5 5
Subwoofer box design All the panels should be made out of 18 mm high-quality, high-strength birch plywood and carefully jointed and glued together. The M-Force transducer exercises a very strong mechanical strain on the box structure as well as very high acoustic pressure at very low frequency. All the accessory and details shown in the project are just an example, you can choose your favorite. 6
A C K L J G H I D M E F C B A. TOP B. BOTTOM C. SIDE D. MEMBRANE PANEL E. MEMBRANE BLOCKING RIM F. DUCT 1 G. DUCT 2 H. AMP CLOSING PANEL 1 I. AMP SPACER J. WHEELS REINFORCE K. AMP CLOSING PANEL 2 L. BACK M. FRONT RING 7
Overall dimensions 8
Internal view and parts dimension Internal view with M-Force transducer in place 9
716 Membrane panel detail (Part ID D) 10
Membrane blocking rim detail (Part ID E) 716 11
12 Internal view and amp housing
Front ring detail (Part ID O) 13
14 Back panel (Part ID L)
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