How to Match Speaker Power With an Amp

By Jonra Springs

Speakers receive power from an amp. The amp will show figures how much power it can put out to drive speakers. The speakers will show ratings for how much power they can handle receiving. Both amplifier and speakers will list a value for how much impedance they utilize. While power comes from amplifiers, impedance is dictated by the speakers. The power ratings for both list watts for power and ohms for impedance. The only other factor to consider is speaker sensitivity. Match speaker power with an amp to get the best possible sound at the highest volume with the maximum clarity.

Step 1

Match the wattage between the speakers and amp. This rating will either be listed as RMS which shows the average power, or the peak power which may be reported as music power. Compare the average power of both speaker and amp, or the peak power of the two. An amp that has an average output of 100 watts per channel will deliver a lot more at it's peak output. Speakers that have a peak rating of 100 watts per channel will not handle the maximum load from an amp with 100 watts RMS. Match speakers with a peak level of 100 watts with amplifiers that put out a peak level of 100 watts per channel.

Step 2

Measure speaker power against the amp output per channel. An amp that puts out 100 watts per channel delivers 100 watts to each speaker, not 25 watts to each of four speakers. Use a speaker rated for 100 watts peak power with an amp that sends 100 watts of peak output per channel.

Step 3

Match the impedance of speakers to the amp. Impedance is listed in ohms with the Greek letter omega. A typical impedance is 8 ?. Speakers for home audio systems may use 4, 6 or 8 ohms. The amplifier must be power rated for the ohms a speaker imposes. An 8 ? amp will not drive 4 ? speakers adequately. Many contemporary amps are rated for 4 to 8 ohms, and can handle any home speaker system. Some amplifiers have a set-up screen that will ask for the impedance rating of the speakers connected. Such amps will run at optimum output for the impedance selected during set-up.

Step 4

Check speakers for sensitivity rating. Speaker sensitivity shows how efficiently the speakers convert incoming power into sound. The rating is listed in decibels with dB or db following numbers between 84 and 100. Buy the speakers with the highest affordable sensitivity. The more sensitive a speaker is, the more volume it will deliver with less power.

Tips & Warnings

  • Exercise caution while raising the volume. All speaker to amp problems arise at higher-volume levels. Once the sound begin to distort, there is a strain on the speakers and possibly the amp also. Even the best-matched audio system can over tax an amp, or overheat the speakers if the volume is turned up too loud.