If the Independent Monitoring Level (for Record Enabled Channel Strips) option in the Logic Pro > Preferences > Audio > Devices > Core Audio tab is enabled, an independent monitoring level is available when an audio channel strip is record enabled. After you arm the track, set the fader to the desired level. The original playback level will be restored when the channel strip’s Record button is disabled.
Note: The Volume fader controls only the playback (or monitoring) level, not the recording level. You must set recording levels externally—on your mixer, or at the original sound source. Take care when you set the input levels, because digital audio will clip when overloaded. Clipping results in a particularly harsh, metallic distortion, so unless you have a penchant for heavier musical styles, overloading the inputs isn’t recommended (see Understanding a Channel Strip’s Peak Level Display).