What is Power Compression?

When you add power to a speaker, there comes a point where its efficiency starts to drop. This phenomenon is called power compression. Essentially, the speaker’s ability to convert electrical power into sound (measured in dB SPL per watt) begins to decrease as more power is applied.

Why Does Power Compression Happen?

Heat Build-Up

As more power flows through the voice coil, it generates heat. This increases the resistance of the coil, reducing the electrical current that can flow through it. As a result, less energy is available to produce sound.

Mechanical Limitations

The moving parts of the speaker—like the cone, surround, and suspension—may reach their physical limits. At high power levels, they may not move as freely, reducing the speaker's ability to produce more output.

Magnetic Saturation

In extreme cases, the speaker's motor (magnet and voice coil interaction) can reach its magnetic limit, further reducing efficiency.

The Effect on Output

As power increases, instead of producing a proportional increase in sound output, the speaker's output levels off. For example:

• Doubling the power might only result in a 1-2 dB increase instead of the expected 3 dB.
• At very high power levels, the speaker might fail to produce any noticeable increase in output.

Key Takeaway

Power compression happens in all speakers and subwoofers. It’s a natural limitation of their design, and it highlights the importance of balancing power with speaker capabilities. Overdriving a speaker beyond its limits can lead to reduced performance, distortion, or even permanent damage.

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