Anyone here had experience with twin parallel wound voice coils.
Mar 28, 2002 at 5:25 PM Thread Starter Post #1 of 4

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Just wondering because I thought using a second coil as a dynamic brake might be a good way of
damping/controlling bass on my planar diapragms if such a problem remains on next version.

I can foresee some potential pitfalls but with the addition of a low pass[notch?] filter accross coil 2 it could reduce the energy at the chosen frequencys no?

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Mar 29, 2002 at 8:28 AM Post #2 of 4

ppl

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only on subwoofers for loudspeakers and i have tried the electronic Break so as to get a larger enclosure volume while still remaining Tight and controlled. The Break can be as simple as shorting one of the windings, OK but better is obtained with another Amp driving the second coil in rev. Phase, Exalent is driving the coil in Phase but with Active Filtering on the input of the other power amp. I used the second order Butterworth filter with a controlable Peak(see thiele Loudspeakers in vented boxes JES may and june 1971) driving the second power amp Able to get Impressive control and Transient responce while using a 12" sub in a 12 Cu Ft vented Box. with a true -3 dB point of 18 Hz and still handel 100 Watts while keeping the coil well within the Magnetic gap. Good luck on this the possibilities are only limited by your creativity.
 
Mar 29, 2002 at 2:25 PM Post #3 of 4

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Thanks for the input PPL
I think to make a dual coil work in my application the first hurdle
[and the most dammed expensive] would be achieving the dual
coil itself!
To keep the mass low and not comprimise the efficiency of the
transducer overall I would need a diaphragm that is copper clad
on both sides for a coil on each with a total diaphragm mass as
close to the single sided version as possible........=custom
laminates=£££.

I may try two coils running parallel to each other on a single sided laminate but you effectively cut the drive coils length/no
of turns hence the effiency worries mentioned, be ok as an experiment but due to those thin tracks it would mean another
professionaly produced etching and more £££.

I have wondered about driving a second coil in reverse phase
with relevant filtering etc but considered using the amp connected
in parallel in antiphase...worries about artifacts poluting the
signal though,a second amp sounds better, but in my application
I hope none of these measures will be needed...I will know
for sure when the MK2s are up and running with good amp etc.
My bass problems aren't that bad!

Like everthing in this audio hobby.
It needs more money....Hell I need more money
eek.gif


Cheers

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