Some people have asked me recently what power amplifiers suitable for driving particular types of loudspeakers. I didn’t realize it at the time but it turns out that not all amplifiers are able to drive each type of loudspeaker that is out there. So I did some research and came up with some guidelines for selecting the proper power amplifier. In this article, I will show you these guidelines which hopefully should simplify your life when purchasing an amplifier for your speakers.
The first guideline is pretty simple. First of all, you need to figure out how hard you want to drive your speakers. That means how much wattage do you want to have when driving the speakers? This seems like a simple question indeed. Because if you have an answer for that question then you can select an amplifier that gives the proper wattage. Power amplifiers are typically rated with their output wattage. However, it turns out that answering this question and selecting the proper amplifier is more involving than meets the eye.
First of all, it is fairly difficult to assess how loud the speaker has to become in order to provide enough volume throughout your room. That is because the sound waves are reflected by walls and propagate throughout the room in a complex system. If you are setting up speakers outdoors then determining the required loudness is fairly straightforward because the sound dissipates in each direction equally. However, indoors it is quite more difficult to assess. It also depends on what type of building materials were used when constructing the room. Some materials tend to absorb sound while others tend to reflect that.
Another thing to consider is that each speaker is different when it comes to sensitivity. Sensitivity determines how much wattage you need in order to achieve a certain amount of loudness from the speaker. Typically the sensitivity is mostly determined by the transducers which were selected by the manufacturer. Some transducers become quite loud at minimum wattage while others require a significant amount of wattage in order to achieve the same loudness. So rather than looking at speaker wattage it is recommended to look at the sensitivity of the speaker. If you have figured out roughly how much loudness you require then based on the sensitivity of the speaker you can determine the amount of wattage that you require.
Once you know the wattage then you can start selecting a power amplifier. However, just looking at the wattage rating of the manufacturer can be very misleading. That is because many manufacturers tend to overstate the wattage that there power amplifiers can actually deliver on a constant basis. Oftentimes the peak wattage is given instead of the RMS wattage. The RMS wattage is much more reliable when it comes to assessing the ability of a power amplifier.