# Dual Voice Coils, whats the real deal?



## Sine Swept (Sep 3, 2010)

Say I have a sealed box, a dual voice coil sub, many sources of power and a spl meter.

I power one coil. What should I expect?

I power both coils from separate amps. ??

I power both coils with a single amp. ??

In each case all power will be equal.

Which one will be louder? Will any of them be?


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## What? (Jun 5, 2008)

Only advantage of DVC is wiring flexibility. 
Running only one coil reduces the efficiency of the driver of about 3dB as well as significantly shifting T/S parameters rendering any enclosure inaccurate unless your remeasure the driver for T/S. 
Above info is from the JL Audio reference manual tutorial #4 DVC FAQ.
JL voids the warranty on any DVC subwoofer that only had one coil hooked up.


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## dannyboyy14 (Jun 29, 2009)

You also usually gain sensitivity when the coils are wired in parallel instead of series. pretty much more output out of the gate. But the series config i have found to be a bit more "stable" and better sounding like it has more control.

You can make the argument it has more flexibility but people usually base their sub needs by what kind of amp they want to run. for example:

lets say 600 watts at 4 ohms bridged is what they recommend. You would want either 1 single 4 coil or a DVC sub that has 2 2 ohm voice coils(run in series to get 4 ohms). if your running 2 subs, you would want 2 single 2 ohm or 2 DVC subs with each coil being 4 ohms(each sub ran in series on its own voice coils, then parallel on the output of the amp) to achieve 4 ohms at the amp.

If the amp can run at 2 ohms you get 1 DVC sub @ 4ohms (run each coil in parallel) each coil to achieve 2 ohms. or 2 subs would be 2 with 2 ohm coils(run the coils in series then the 2 subs in parallel).

if you buy an amp rated for 600 watts at 4 ohms, and you have a DVC 4ohm each coil sub, you would have to run this config at 8ohms which cuts your power to the sub in half. Because running at 2 would most likely put the amp into protection or blow up your equipment.

If you have 1 coil hooked up the sub will still function but will lose output as What? stated. 
If you have 2 amps, you will need to match the gains using a DMM to ensure you are not overdriving just 1 of the coils. This gets tricky also because if you run a 2 channel amp (1 channel to each coil) then you have 2 different signals going into each voice coil due to the left and right signal and it may not be as good as precombining the signal at the amp and putting it in bridged mode. The sub would only see one signal then. 

I would look at getting a 1 channel or 2 channel amp (bridge it so you don't have 2 different signals on 2 different coils) looking at the specs and ohm ratings, then make the decision for 1 or 2 subs and figure out the best coil setup for the amps application.


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## syc0path (Jan 23, 2013)

Sine Swept said:


> I power one coil. What should I expect?


 3dB+ loss in efficiency and shifted T/S parameters



> I power both coils from separate amps. ??


Still some loss in efficiency due to the fact that it's virtually impossible for both amps to produce an identical signal due to production tolerances, access to vehicle power, etc. Whether or not this loss in efficiency would be audible is debatable.



> I power both coils with a single amp. ??


The best choice. But don't use 2 separate channels from a single amp, for the same reason that u should use separate amps. Use a monoblock amp or a bridged channel.


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## Jepalan (Jun 27, 2013)

I ran one VC of a JL Audio 10TW3 for a year because my 5 channel amp couldn't handle 2 ohms. I shorted the other VC with a jumper based on an article I read. It sounded *awesome* and I never had a problem.

When I upgraded to a 5-channel amp that could run 2 ohms I paralleled the VCs and everything was still happy. Honestly I could not tell one bit of difference in SQ at my normal listening levels and using the same sub enclosure.

IMO - the only advantage of dual VCs is the wiring and amp choice flexibility. Period.


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