I have a 15 W + 15 W amplifier per channel, it will give 15 W at 4 ohm and 10 W at 8 ohm. My speakers are 4 ohm, 10 watts. Do I add 4.7 ohm 5 W wirewound resistors in series with each speaker? Will this save my speakers? Will it affect the sound quality?

  • \$\begingroup\$ Please link to the documents that define the specification for the amplifier and speakers. \$\endgroup\$
    – Andy aka
    Jan 1 at 13:54
  • \$\begingroup\$ Electrical product usage question. Obviously the amplifier will not give 15W to speaker unless you turn the volume too high, and typical speakers give 80 dB SPL at 1W measured at 1 meter, so if the speaker can handle 10W, at 10W you likely get hearing loss before the speaker burns out. \$\endgroup\$
    – Justme
    Jan 1 at 14:17
  • \$\begingroup\$ Driving speakers from a higher rated amp (within reason, not a 200W amp here) is common and safe practice. A too-small amp, driven into clipping (audible distortion) produces high harmonic content, which is more likely to damage the speakers than a too-large amp driving the speakers short of audibly overloading them. Relax and enjoy the music! \$\endgroup\$ Jan 1 at 16:47

1 Answer 1


You can add series resistors but it affects the amplifier's ability to control the speaker properly.

Instead, just use your ears to detect onset of distortion and turn down the volume when you hear it.

  • \$\begingroup\$ @Abrar - A series resistor will create a poor damping factor, an undesirable characteristic. en.wikipedia.org/wiki/Damping_factor \$\endgroup\$
    – Mattman944
    Jan 1 at 14:08
  • 1
    \$\begingroup\$ Resistor can be added, but there is just no reason to add it. \$\endgroup\$
    – Justme
    Jan 1 at 14:18
  • \$\begingroup\$ 15W continuously into a 10W speaker might blow the speaker. But nobody plays a continuous tone at full power. The average output power for music is 1/10th the maximum continuous undistorted power. Except, acid rock produces almost continuous full power noise. Some amplifiers and speakers are rated in Peak or Maximum power that is simply double the real power. \$\endgroup\$
    – Audioguru
    Jan 1 at 17:35

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