Q: Why is the "Speaker Volume" knob on my OX controlling the level of the headphone, line, and/or digital outputs?
A: This is a symptom of having OX connected incorrectly to your amplifier and speaker. This issue will occur when your amplifier's powered output is incorrectly connected to OX's "TO SPEAKER" jack and/or when OX's "FROM AMPLIFIER" jack is connected to your speaker. Connecting your amp to OX backwards like this can also cause low output levels to your speaker, even when the "Speaker Volume" knob is set to 5.
To correct this issue, check the connections between OX and your amplifier to make sure the amplifier's powered output is connected to OX's "FROM AMPLIFIER" jack and that the speaker is connected to OX's "TO SPEAKER" jack. When OX is connected to your amp properly the headphone, line, and digital output levels can be controlled independently of the speaker volume for silent operation.
For details, see the amp & speaker connection diagram in this article.