Audio Tapers vs. Linear Tapers

Variable resistors consist of a strip of resistive material (connecting lugs 1 and 3) with a wiper (lug 2) moving over them. If you measure the resistance across lugs 1 and 3, you’ll find that it is always the same as the marked value of the pot, regardless of the position of the wiper. Meanwhile, the resistance between either outer lug and the middle lug varies as you run the wiper, from zero to the marked value of the pot. The resistive material running between lugs 1 and 3 is tapered, so that it offers varying resistance as the wiper moves across it. Most pots have a linear taper: when the wiper is at its halfway point, the resistance is half of the marked value of the pot; when it is at its 3/4 point, it is 75 percent, and so on. This is great for most electrical signals but lousy for controlling the apparent volume of audio sources, since we perceive amplitude logarithmically (i.e., in order for a sound to seem twice as loud, it must actually be exponentially more powerful). To address this problem, some pots have a taper that approximates a logarithmic progression; these are called audio tapers. The takeaway: Always use audio tapers for volume controls and linear tapers elsewhere, unless otherwise noted.