Subwoofer Wiring Diagram: Series, Parallel, and Ohm Loads

Wiring a subwoofer incorrectly -- giving a 2-ohm-stable amplifier a 0.5-ohm load, or giving a 4-ohm-stable amp a single-ohm load -- either damages the amplifier or leaves significant power on the table. Getting the impedance right requires understanding how your subwoofer is built (SVC vs DVC) and how series and parallel connections change the total impedance the amplifier sees. This guide covers SVC and DVC subwoofer wiring, single and multi-subwoofer configurations, and how to match the result to your amplifier's stable impedance.

SVC vs DVC: What's the Difference?

SVC (Single Voice Coil)

An SVC subwoofer has one voice coil with two terminals. The coil impedance is fixed -- you buy a 4-ohm SVC or a 2-ohm SVC, and that's what the amplifier sees. There is no wiring flexibility with a single SVC sub; the only variable is how you connect multiple SVC subs together.

Common SVC ratings: 4-ohm, 2-ohm, 8-ohm.

DVC (Dual Voice Coil)

A DVC subwoofer has two independent voice coils wound on the same former, sharing the same magnet. Each coil has its own pair of terminals. The two coils can be connected in series, in parallel, or each coil can be driven by a separate amplifier channel.

A DVC 4-ohm sub (each coil = 4 ohms) can be wired to present:

A DVC 2-ohm sub (each coil = 2 ohms) can present:

DVC subs are popular in car audio because they give you flexibility to match common amp impedance ratings.

Series vs Parallel -- The Basics

Series Connection (increases impedance)

Two impedances in series add directly:

Z_total = Z1 + Z2

Two 4-ohm coils or subs in series: 4 + 4 = 8 ohms

Parallel Connection (decreases impedance)

Two equal impedances in parallel divide by the number:

Z_total = Z / n (for equal impedances)

Two 4-ohm coils or subs in parallel: 4 / 2 = 2 ohms

For unequal impedances: Z_total = (Z1 × Z2) / (Z1 + Z2)

Single DVC Sub Wiring Options

DVC 4-Ohm Sub -- Series (8 ohms)

Connect the positive terminal of coil 1 to the amp positive. Connect the negative terminal of coil 1 to the positive terminal of coil 2 (internal daisy chain). Connect the negative terminal of coil 2 to the amp negative.

Amp (+) --- [Coil 1 +] ~~~ [Coil 1 −] --- [Coil 2 +] ~~~ [Coil 2 −] --- Amp (−)
Result: 8 ohms

DVC 4-Ohm Sub -- Parallel (2 ohms)

Connect both coil positives together and to the amp positive. Connect both coil negatives together and to the amp negative.

Amp (+) --- [Coil 1 +] and [Coil 2 +] together
Amp (−) --- [Coil 1 −] and [Coil 2 −] together
Result: 2 ohms

DVC 2-Ohm Sub -- Series (4 ohms)

Same as DVC 4-ohm series, but each coil is 2 ohms: 2 + 2 = 4 ohms.

DVC 2-Ohm Sub -- Parallel (1 ohm)

Both coils in parallel: 2 / 2 = 1 ohm. Only use this configuration with an amplifier that is stable at 1 ohm. Running a 1-ohm load on an amplifier that is only rated to 2 ohms is a reliable way to destroy the output stage.

Two-Subwoofer Wiring Configurations

Two SVC 4-Ohm Subs -- Series (8 ohms)

Sub 1 positive to amp positive. Sub 1 negative to Sub 2 positive. Sub 2 negative to amp negative.

Amp (+) --- [Sub 1] --- [Sub 2] --- Amp (−)
4Ω + 4Ω = 8 ohms

Two SVC 4-Ohm Subs -- Parallel (2 ohms)

Both sub positives to amp positive, both sub negatives to amp negative.

Amp (+) --+--- [Sub 1] ---+-- Amp (−)
          |               |
          +--- [Sub 2] ---+
4Ω ∥ 4Ω = 2 ohms

Two DVC 4-Ohm Subs -- All Coils in Parallel (1 ohm)

Each sub has two 4-ohm coils. Four coils of 4 ohms each in parallel: 4 / 4 = 1 ohm.

Two DVC 4-Ohm Subs -- All Coils in Series (16 ohms)

Four coils of 4 ohms in series: 4 × 4 = 16 ohms. This is rarely useful in practice -- most amplifiers produce very little power into a 16-ohm load on their subwoofer output.

Two DVC 4-Ohm Subs -- Series/Parallel (4 ohms, typical competition config)

Wire each sub's two coils in series (8 ohms per sub), then wire the two subs in parallel (8 / 2 = 4 ohms). This is the most common competition-grade wiring for two DVC 4-ohm subs -- you get 4 ohms, which is the "comfortable" stable impedance for most monoblock amplifiers.

Alternatively: wire each sub's coils in parallel (2 ohms per sub), then wire the two subs in series (2 + 2 = 4 ohms). Same result, same total impedance.

Amplifier Stable Impedance -- Why It Matters

Every car audio amplifier has a minimum stable impedance specified in its data sheet. Below this rating:

Common amplifier stable impedance ratings:

If your amplifier datasheet says "stable to 2 ohms," wiring your subwoofer for a 1-ohm load will likely destroy the amplifier, void the warranty, or both.

Bridged Amplifier and Impedance

When a stereo amplifier is bridged to mono (combining both channels to drive a single subwoofer channel), the amplifier sees double the actual load impedance:

The rule: a bridged amplifier behaves like each channel driving half the load impedance. If the amp is 4-ohm stereo stable, the minimum bridged load is 4 ohms (which each transistor sees as 2 ohms). Never bridge an amplifier into less than twice its rated minimum impedance.

Voice Coil Phasing

When wiring two coils (DVC) or two subs in parallel, polarity matters. Both coils must push the cone in the same direction simultaneously, or they work against each other.

For a DVC sub with coils in parallel:

If one coil is wired backward (positive to amp negative and negative to amp positive), the two magnetic fields oppose and the speaker produces almost no output -- the coils mechanically fight each other. This is a common mistake when wiring from the back of the basket where the positive terminal is not always visually obvious.

Terminal marking varies by manufacturer: look for a + symbol, a red terminal, or a marking like "T1+" and "T2+" to identify the positive terminals of each coil.

Create Your Own Subwoofer Wiring Diagram

Planning the exact wiring before cutting wire and crimping terminals prevents impedance mismatches and polarity mistakes. With CircuitDiagramMaker, you can:

Create your own subwoofer wiring diagram -- free

Key Takeaways