Speaker Power & Distance

Speaker Sensitivity

When designers and engineers consider a speaker to integrate into their product, most focus on the speaker’s power handling as a gauge of how loud a speaker can play and it’s quality.

More attention needs to be paid to the sensitivity rating of a speaker, which we call out as the SPL rating on our speaker specifications. This SPL rating is listed with a given input at a fixed distance. When both the power handling and SPL ratings are considered, one can start to get the true picture of a speaker’s maximum output capability.

The Effect of Power on SPL

You have to double the input power to produce a 3 dB increase in sound output (assuming the speaker is not reaching its limits). Therefore we can produce a table for how loud the speaker will play with a specific starting power.

For each doubling of input power to the speaker, there will be a 3 dB increase in output. Take note of the power handling limit highlighted in yellow. What this illustrates is that additional power only adds a small amount of additional sound pressure over the initial SPL measured with 1 watt of input power. With most speakers, 80% to 90% of their maximum output is generated in that first watt.

Many customers exceed the speaker’s power rating to squeeze just a little more output from a speaker. While this might not immediately damage the speaker, it does place additional stress on the tinsel leads (circled in red below) that connect the electrical terminals to the speaker’s voice coil. If stressed for too long, these will break, and the speaker will fail to operate.