Understanding Ohms & Impedance

Ohms and impedance are some of the most important — and misunderstood — concepts in car audio.

You don’t need to be an electrician, but you do need to understand how impedance affects amplifiers,
subwoofers, wiring, and system safety.

If you skip this topic, everything downstream becomes guesswork.

What Is Impedance?

Impedance, measured in ohms (Ω), is the resistance a speaker or subwoofer
presents to an amplifier when playing music.

In car audio:

• Lower impedance = heavier electrical load
• Higher impedance = lighter electrical load

Most car audio equipment uses nominal impedance ratings such as 1, 2, or 4 ohms.

Why Ohms Matter in Car Audio

Impedance directly affects how much power an amplifier can produce.

For example:

• 500 watts RMS at 2 ohms
• 300 watts RMS at 4 ohms

This is why impedance is just as important as RMS vs Peak Power.

How Impedance Affects Amplifiers

Every amplifier has a minimum stable load.
Running below that load can cause overheating, protection mode, or permanent damage.

Always verify impedance before wiring speakers or subwoofers.

SVC vs DVC Subwoofers

Subwoofers are available in:

• Single Voice Coil (SVC)
• Dual Voice Coil (DVC)

DVC subwoofers provide wiring flexibility, not better sound quality.
Learn more in SVC vs DVC Explained.

Series vs Parallel Wiring

• Series wiring increases impedance
• Parallel wiring decreases impedance

This is covered in detail in Series vs Parallel Wiring.

Why Lower Ohms Isn’t Always Better

Lower impedance increases power output, but also increases heat and electrical stress.
Many systems perform better and more reliably at 2 or 4 ohms.

Impedance, Clipping, and Speaker Damage

Impedance alone does not damage speakers.
Problems occur when amplifiers clip or are run below their stable load.

Learn more in What Is Clipping and Why Speakers Blow.