If your headphones sound dull, your guitar feels lifeless, or your home stereo sounds muffled, you might be dealing with output impedance. Here’s what you need to know about output impedance and why it’s such a drag on your stereo.

To understand output impedance, we need to explain some basic electrical engineering. When you transport electricity from one place to another through a wire or other conductive material, not all of the energy gets through. Think of it as pouring hot water over coffee grounds and a filter in the morning; most of the water gets through, but not all of it.

So you lose some of the energy, often in the form of heat. This is called resistance.

Next, you have to consider that you can only squeeze so much electricity into a material. It’s like running water through a pipe; big or small, there comes a point where the water in the pipe has to flow out before more can go in. This is called capacitance.