# How Efficient is a Speaker at Turning Electrical Energy to Sound Energy?

Choosing the right speaker can be a daunting task, especially for those who don’t have the technical knowledge of audio equipment. One of the most important factors to consider when selecting a speaker is its sensitivity rating. In this article, we will discuss how sensitive a speaker is and how much power it requires to achieve a certain volume.

Speaker sensitivity is a relationship between three factors: decibels, sound pressure level, and power. Decibels are a measure of sound pressure level, which is the physical energy that our bodies have to handle. The higher the sound pressure level, the higher the dB, and the lower the amount of time that we can expose ourselves to that energy before we begin to experience pain or hearing loss.

To achieve a dynamic range of sound while being safe, we need to target a range where the system is calibrated to deliver that dynamic range without harming our hearing. For most people watching a movie, that range is about 85 to 90 decibels of energy for a prolonged exposure of two hours. Ideally, 87 dB is our target.

Let’s look at the relationship between decibel output and power for a speaker sensitivity rating of 90 dB at 1 watt at 1 meter. If we double the power from one watt to two watts, we add 3 decibels of output to 93 decibels. Every time we double that power, we add another 3 decibels. So at 4 watts, we get 96 decibels, and at 8 watts, we get 99 decibels of output.

However, it is essential to keep in mind that the speaker’s sound pressure level is measured at one meter distance from the speaker. Your listening position is likely to be three to four meters away from your speaker. As we double the distance on that sensitivity rating, we remove six decibels of energy from the system. This means that at 2 meters, the speaker’s sound pressure level drops back to 93 dB, and at 4 meters, it goes back down to 87 dB, which is our target.

The sensitivity rating of a speaker is different from speaker to speaker, and if we keep the distance to our listening position the same, we will need either more or less power to achieve the same decibels at that listening position. An 87 decibel sensitivity rating speaker will require twice as much power, while a 93 decibel sensitivity speaker will require half as much power to achieve the same listening level at your listening position.

In conclusion, understanding and selecting the right speaker sensitivity rating is crucial in achieving the desired sound quality while keeping our hearing safe. By following the guidelines discussed above, you can make an informed decision and enjoy your music, movies, or TV shows with the perfect sound quality.