A simple chain vs a more complex chain in Ozone 8—signal flow goes from left to right
Auxiliary sends (a.k.a sends) are used during recording sessions for purposes such as headphone mixes and reverb configurations because they can easily route a duplicate signal to a different destination than the track output. Remember that sends are duplicating (splitting) the signal and therefore do not affect the signal that is on the normal signal flow path in the track.
In this way, using a send differs from busing the output of the track. Granted, sends and buses are alike in that they allow you to route signal from one or more tracks to a common destination. However, whereas a send duplicates the original signal before or after the fader and doesn’t change the original signal’s output, busing the output of the track does not duplicate the original signal and instead changes the original signal’s output after the fader. As a result, buses are used primarily in mixing for summing tracks and routing to other tracks. Access to buses is at the track output, just after the pan.
As for sends, in they go to the signal flow!
Sends can generally be set to one of two positions, pre-fader or post-fader.
Pre-Fader: the send will be before the track fader. No matter what you do with the track fader, the send level remains the same. This is normally preferred when routing sends to headphone mixes because the send levels feeding to the artists won't be affected by level changes to the track faders. This allows separate mixes to be made for the engineer and one or more artists.
Post-Fader: the send will be after the track fader. Any level change to the track fader will affect the level of signal to the send. This is normally preferred when routing sends to time-based processors such as reverbs and delays because it allows the ratio of original to affected signal to remain fixed even as the main track fader is adjusted.
With the sends in place, the resulting signal flow order is:
Hard drive > insert #1 (compressor plug-in) > insert #2 (EQ plug-in) > pre-fader send > fader > post-fader send > pan
Everything else about the basic signal flow remains the same.
Two important facts about this order:
1. The plug-ins (in the insert positions) affect what goes to pre- and post-fader sends. So, if you are going crazy with EQ changes, those tweaks will absolutely affect the signal to both pre- and post-fader sends.
2. Sends do not affect the recording or the level going through the track fader. This means that you can adjust the send levels without impacting the main signal level in the track.