Excerpt from http://www.openbsd.org/faq/faq13.html
"As a basic example of common mixerctl usage, to set the volume of the left and right channels to 200, you would issue $ mixerctl outputs.master=200,200 outputs.master: 255,255 -> 207,207 Notice how the value becomes 207. The reason for this is that this audio device has an AC'97 codec, which uses only 5 bits for volume control, leading to only 32 possible values. Other hardware could have different resolution." The rest of the FAQ is interesting, too.
