Speakers – Does Driving a Speaker with DC Offset AC Signal Matter


Do these two input signals have different effects on a speaker?

  • An AC signal with some value of DC offset.
  • Same AC signal but centered at 0 V.

Best Answer


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Figure 1. Cutaway view of a dynamic loudspeaker for the bass register. 1. Magnet, 2. Voicecoil, 3. Suspension, 4. Diaphragm. Source: Wikipedia.

A DC component in the signal will cause:

  • Bias of the speaker cone (4) and the suspension (3) from the neutral position. This means that the cone will reach the limit of its travel - or at least where it becomes highly non-linear - in one direction in a shorter distance compared with the other.
  • Maximum undistorted volume will be decreased as a result.
  • The coil (2) will be heating even when no audio is playing.