okay, the above is incorrect...or confusing me so much that it's incorrect
inserts and sends are two different ways of adding effects to a track. To make it simple, always use sends to apply a time based effect and inserts to apply a dynamic based effect.
What happens with inserts is that the effect is
inserted into our signal path, effectively replacing our original signal.
With sends (you'll also hear the term aux send used), our source signal is
copied, sent to a time based effects unit, then sent back to an Aux master or two open channels.
Now, when do you know when to use each one? Well, the reason we use an insert with dynamic based effects (EQs, compressors, limiters, gates, etc.) is because we actually DO want to replace our signal with the new effected signal. The source signal hits that insert patch point on the mixer and goes out to the dynamic processor. We use a special cable called an insert cable (which is pretty much just a Y cable with a single TRS lead on one end and two TS leads on the other) to accomplish this. So the signal goes to the processor and returns back on the same cable to the point where it left on the mixer. It's just kind of a little detour for our signal. Now what you hear is the effected signal...compressed, EQed, gated, whatever.
With time based effects (chorus, reverb, delay, etc.), you generally want to blend the original source with the effected. We use aux sends to do this. On a mixer you will see an Aux Send knob on each channel. This turns up the volume to
copy our source signal out the aux send patchpoints on the mixer. This generally goes out mono, to an effects processor, and then back in stereo. You usually return it to an aux master point which will give you a single fader/knob control over the newly effected signal, or to two open channel I/Os so you can add more EQ, another time based effect, a compressor...etc.
We don't use an insert because again, you want to blend it with the original signal. We call the effect signal "wet" and the original source, "dry." For example when applying reverb to a vocal it's nice to have the "dry" signal and add a little bit of "wet" for effect. If we had just inserted it we may find it sounds way too verby for our tastes....using an aux send gives us more control over the blend of the two.
So in your example of "you shouldn't add chorus as an insert..." I'd agree. Chorus should be on a send so that you have more control of wet vs. dry signal
Of course, these are generally good rules to follow but can easily be broken.
Aux sends are also used for headphone/cue mixes (because you can just copy the signal to create a headphone mix instead of inserting, which breaks our signal).
HTH
