The Latency Bundle is a tool for measuring and compensating latency, purpose-built for Logic Pro. The bundle contains the Latency Detector and the Latency Compensator.
The Latency Detector is a tool to measure delay times and analyse latency. Most plug-ins require a given amount of time to process an audio signal, therefore only allowing the signal to pass with a certain delay. This delay is known as latency. Most sequencers, however, like Logic Pro, have a mechanism to offset latency, ensuring that all tracks are perfectly synchronised. However, this compensation does not work when using the I/O Plug-In to route signals to and from external audio hardware.
The latency induced by I/O plug-ins is not deduced and cannot therefore be automatically compensated. The sequencer obviously cannot know what is happening to the signal in the outside world. To find out the latency of an I/O Plug-In, the sequencer would have to measure the time required for the signal to leave the sequencer output and reappear at the input.
Using the Latency Detector this measurement can now be carried out exactly and the determined latency value can be used in the Latency Compensator to make up for the delay.