Single voice-coil (SVC) or Dual voice-coil (DVC) subs?

[Ryan from Ohio]

First, let me state that there is NO difference in sound, or performance between an SVC, and a DVC subwoofer.
The only difference between the two types of subs, all else being equal, is the load presented to the amplifier. The reason this is done by the manufacturer is to offer a wider range of wiring options, for more versitility.

Subs come in some of the following loads:
Single Coil: 2, 3, 4, 6, and 8 Ohms
Dual Coils: 1.5, 2, 3, 4 and 8 Ohms *per* coil

The most common configurations are 4 and 8 Ohms for an SVC subwoofer, and 4 Ohms per coil for a DVC subwoofer.

If you're trying to decide which subs to get, first you need to choose your amplifier. Based on the amplifier's number of channels, and load-stability (2-Ohm stable for example, which is the standard though not the rule) you can decide on subs that will match up to the amplifier in both load, and power rating.

Here is a link to a wiring wizard supplied by Rockford Fosgate, to help understand how to wire your subs based on teh coils and load.

A single-coil sub with a 4 Ohm coil, will present a 4 Ohm load to the system.
A dual-coil (DVC) sub with two 4-Ohm coils, is designed to present either a 2-Ohm load by wiring the coils in parallel (see wiring wizard link) or an 8-Ohm load by wiring the coils in series.
It is not recommended that you run separate channels of an amplifier, or separate amplifiers to each coil of a DVC subwoofer. This requires VERY fine tuning to balance the channels, through the use of an RTA (real-time analyzer) and an oscilloscope. If this calibrating is bypassed, the coils will not receive precisely identical signals, and that desynchronization will cause the coils to fight each other, and what you'll end up with is a very nice, very large paper weight instead of a subwoofer. The resulting damage will consist of a fried voice coil(s).
NEVER wire a DVC subwoofer with just one of the coils, and leave the other disconnected!
This will result in instant damage to the driver, and once again, you'll be looking at buying a new speaker.

Another note: a bridged stereo amplifier will NOT produce any more power than it will in streo mode. This is a common misconception. The total RMS power output of a stereo amplifier into a 2-Ohm stereo load is equal to the total RMS power output of the same amp, bridged, into a single 4-Ohm load.
Remember, when an amplifier is bridged, it's minimum load is doubled. In other words, if the amplifier can handle a 2-Ohm load in stereo, it will only handle a 4-Ohm load when bridged!

If you're looking for an amplifier for subwoofers, generally speaking, a mono amplifier is your best choice. These are usually designed solely for driving subs, they offer more power than other stereo amplifiers for the same price, and have convenient features such as built-in low-pass filters. With such an amplifier, you usually want to plan for a 2-Ohm load, total, for the subs.
(Two 4-Ohm subs, one 2-Ohm sub.. whatever you like)

for more information on DVC subs, see the JL audio site, here:
http://www.jlaudio.com/tutorials/dvc/index.html

Text Originally Posted by Kiki the Cat