MōTIV Tutorial Complete development of a transducer motor in under 30 minutes Dan Wiggins and Mark Beach, DYNE Analytics Copyright © 2013 Dan Wiggins. All Rights Reserved. For ALMA and instructional use only!

Typical starting point MAYBE box use? 15L/47 Hz Sketchy, at best! Use the TS Parameter Wizard Nominal Size6.5 Inches Cone MaterialAluminum Cone ShapeCurvilinear/constant radius Cone Finish & ColorBlack anodized matte DustcapConcave, end of former mount Dustcap MaterialBlack anodized aluminum Surround MaterialNatural Butyl Rubber Surround ShapeS Roll Basket MaterialAluminum, 35mm ID, 4mm thick Voice Coil Diameter25.4mm (1 inch) Voice Coil WireCopper Spider MaterialCONEX40 Magnetic ShieldingNo Terminal SizesPositive: 0.25” Negative: 0.187” Re6.5 Ohms Le at 1 kHz 0.26 mH Fs 45 Qts.36 Qms 3.6 Vas 22 liters Sd 126 cm² SPL/w/m 89 1W, 1m Xmax (BL) 4mm one way minimum Xmax (Mechanical) 10mm one way minimum Power Handling 50W RMS What do we want? Copyright © 2013 Dan Wiggins. All Rights Reserved. For ALMA and instructional use only!

Set up the voice coil VCID as needed Copper wire as needed Low Le = few layers Set Winding length assuming 6mm top plate Set former – power dissipation Proper DCR, Le looks promising! Copyright © 2013 Dan Wiggins. All Rights Reserved. For ALMA and instructional use only!

Set up the motor Typical clearances for voice coil Use existing magnets Is Xmech OK? Typical materials Turn off Le for now – speed! Turn off Load Lines – speed! Simulate the results – OK? Copyright © 2013 Dan Wiggins. All Rights Reserved. For ALMA and instructional use only!

Application Definition Ignore environment for now Define driver No need for filters now We know the Mms of the VC; add extra mass to get us where we need to be Copyright © 2013 Dan Wiggins. All Rights Reserved. For ALMA and instructional use only!

Run and Results VC offset issue? Low BL – bigger magnet? Pole saturated a lot – make the ID smaller? Consider inductance rings Xmax low – longer VC! Copyright © 2013 Dan Wiggins. All Rights Reserved. For ALMA and instructional use only!

VC and BL tweaks Duplicate to concept 2 Pole ID – smaller for more flux flow Magnet – DMEGC 3614 of Y30BH Adjust steel for different size of magnet Pole extension – get VC offset to zero VC longer – add 2mm, adjust wire diameter to keep DCR Copyright © 2013 Dan Wiggins. All Rights Reserved. For ALMA and instructional use only!

Run and Results Compare against concept 1 Good Xmax Good T/S parameters THD is down – good! Still some saturation – good! Box alignment looks flatter We’ve nailed out the basics Copyright © 2013 Dan Wiggins. All Rights Reserved. For ALMA and instructional use only!

Inductance optimization Make it flat! Consider effect of aluminum basket Lower ring – closer to VC is good! o Start with aluminum o 1mm thick ring o Close to VC Activate Load Lines – check! Activate Le calculations o Use relevant frequencies Copyright © 2013 Dan Wiggins. All Rights Reserved. For ALMA and instructional use only!

Run and Results Le looks good – can we go thinner? Fairly symmetric Is the 250 Hz line OK? Check load line – bump up power to peak 100W Copyright © 2013 Dan Wiggins. All Rights Reserved. For ALMA and instructional use only!

Save and document Add appropriate notes to file for your own records Dump out into a nice HTML file – anyone can read Maybe see if you can refine other topologies? o Underhung o XBL™ Copyright © 2013 Dan Wiggins. All Rights Reserved. For ALMA and instructional use only!

Compare different topologies Took about 5 minutes per motor Quick comparison of different models Overhung – big power handling, simple, normal Underhung – lower THD, thicker top plate, same magnet mass, Le issues XBL – lower THD, top plate between OH/UH, more stroke, same magnet mass, better Le Copyright © 2013 Dan Wiggins. All Rights Reserved. For ALMA and instructional use only!

Questions and wrapup THANK YOU! Copyright © 2013 Dan Wiggins. All Rights Reserved. For ALMA and instructional use only!