Audacity 4 documentation · Primary-source explanation; examples are illustrative. Instructions are based on publisher guidance; a UK IPTV account was not tested on this platform.
Identify which delay is troublesome
Audacity Audio settings documents latency compensation for recording alongside existing tracks and distinguishes it from buffer size. First establish whether the complaint is that a newly recorded track lands late on the timeline or that the performer hears their live input late in headphones. Those observations can occur together, but they do not describe the same point in the audio path and should not share an unexamined correction.
Measure the alignment with a repeatable reference
The official support repository describes recording a played reference and comparing corresponding sharp events, then recording again to check compensation. For an original arithmetic example, a measured separation of 0.160 seconds is 160 milliseconds. That is an observed interval for the chosen input, output and host, not a universal setting. Follow the installed version documentation for entering its correction; the older support procedure uses a negative measured value and its interface names predate the rebuilt Audacity 4 controls.
Recheck when the audio route changes
Record the host and selected devices with the result. The support procedure requires a new test when those change, since a different route can have different delay. Keep a stable buffer setting during the comparison and assess live monitoring separately. A smaller buffer trades response against processing stability according to the current manual. Review the recorded alignment after stopping, and avoid describing an offset correction as proof that the performer now hears an instantaneous live signal.