As said: Ratio at mid-rotation.
A Linear will tend to be 50% at half way.
But consider a radio volume knob. You may want a weak station playing loud, or a strong station played soft. This is around 100:1 range of desired gains. If you try it with a Linear, the "strong played soft" gain happens about 1% rotation, or on a 0-10 scale, about "0.1". It is incredibly twitchy for low-gain settings. It also "doesn't do much" from 10 to 7 (your ear is more log than linear).
The old standard "Audio" taper was 10% at mid-rotation. Formed from two linear segments such as 90K and 10K. This gives a good spread of gains 10-6, and 5-1, with tolerable jump 6-5 and 1-0.
("Audio" pots with more sections to get the gain change very smooth have been made but are too expensive outside major studios.)
(True part-LOG pots were made for electro-mechanical computers but way too expensive for audio use.)
Some jobs do not need the full 10%-center taper. Also a 10% taper is very hard for the pot-maker to do (at the low-low prices we like). There has been a tendency to less taper. My observation is that general "Audio" pots tend to 20% taper, but I know 30% is used in some specific designs.
Taper is purely a user problem. Linear always works. But the knob "normal" setting may be far off from center for a log ear and a lin pot, and some of the range may feel all cramped-up at the end of rotation.
In simulation you can always use Lin, sweep your curves 0-10, then hand-adjust the simulated pot to find a nice "normal" curve. If "normal" happens around 10%-30%, buy "Audio" taper so the feel is generally right.
Topic: Differences between pots (Read 2358 times)