any1 ever do any testing on SVC vs DVC

[zinda 10+ year member]

I'm curious if there has been any real world testing done on Single Voice Coil subs vs Dual voice coils? What is the SPL gain when using 1 coil of a DVC then when using Both coils in parallel? Difference in using 2x4 ohm SVC's in parallel vs 1 DVC same way. Is there any real gain with a DVC other than making your amp work twice as hard? Also what happened to the Amps when using 1-DVC, does the Mechanical Resistance fluctuate dramatically when driving both voice coils? Forcing more watts out of an amp doesn't always make for better set up when you consider extra current draw, heat, distortion and if there is a real gain to justify these drawbacks?

I know when I used 8 ohm midbass I heard only very slight difference in overall loudness compared to when I switched from 4 ohm (had 2x6.5" in each front door active crossover at 90Hz & tried 120Hz supplied with 100w RMS ) Never had to replace the 8 ohm, but went through 4 ohm pretty quickly. I realize the 8 ohm got less power but still had very little difference in sound.

If there is any testing done on subs please direct me to where I can see the conclusions.

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[whitedragon551 5,000+ posts]

Absolutely no difference. All the SVC and DVC options give you is the ability to wire down to different ohm loads to match your amp.

 

[zinda 10+ year member]

But there has to be some gain in output at the cone surface due to the extra watts that the amp is producing, and the 2 separate subs will have twice the driver surface area so they must move more air since the max excursion of the speakers (if made by the same company and same models other than the coils) is going to be roughly the same. The DVC might have faster response with more wattage also. I can't even believe that they have no difference in sound. There has to be a lab that has done some real world sound room testing, if there is none, then maybe it's time to do this. Having 2 coils has to effect the Mech Resistance of the speaker while it's powered hard. The nature of what makes any electromagnet work has to effect the fields when they are acting on the same pole? Plus heat build up on the coils/pole will be a major influence on sound output, failure to dissipate the heat is the main factor in speakers ability to accurately control the cone and the cause of the coils & windings burning up.

 

[fasfocus00 5,000+ posts]

Absolutely no difference. All the SVC and DVC options give you is the ability to wire down to different ohm loads to match your amp.

spot on, its just wiring flexibility and thats it.

 

[05trailblazer 10+ year member]

ohms law is awesome.

 

[zinda 10+ year member]

After some research I have found no conclusive testing results done by any testing labs that show any waveforms or spl test results. Furthermore I have now learned what or from what the DVC sub was made to do. It seems that the second voice coil was originally added to control or correct any spikes in output frequency that may occur, whether it's caused by speaker enclosure or placement. What was done was a test was run after the sub was installed and the second coil was used in reverse polarity along with a crossover and a resistor to use the bandpass signal sent to it to reduce any uneven output in an attempt to flatten the response!? I'm guessing old subs had major spikes in their response that was unique to each individual sub, probably due to hand made speakers having no set production type assembly. Resulting in varied response from person to person on who assembled them or even which types of materials were used in manufacturing if the Companies got new materials that varied from their suppliers.

I don't have any of the original manufacturers names who did this, I'm sure it was used on cheap subs as an easy way to achieve near flat response on each speaker without having to buy an EQ that will only correct overall sound and would be harder to "fix" sound in problem areas that have multiple subs in different locations like in a movie theater, corner locations may be boomy while center located would seem flat and with an EQ it would ruin the center sound when attempting to flatten the corners.

Overall the design may have changed from the original concept, since the response has stopped fluctuating wildly due to controlled manufacturing techniques and better modeling. What they were designed to do originally is something that was never con-vied or even considered when they started making the new DVC subs. I highly doubt that anyone has even thought about using a sub in this fashion for any car audio application?

I'll bet very few people even knew this was the original intended use of the second coil.