Technically, the pre fader send bus and post fader send bus aren't bus's since no signal summing is happening in the picture. We only have one mic channel on our mixer. If we had two mic channels, these effect channels would most certainly be bus's. I hope you can imagine another mic channel in the picture. It makes things easier on my kindergarten drawings skills. (where's dwillis45 when you need him?). If it helps, think of them as taxis instead of bus's since there's only one passenger.
The mic signal comes in at the mic preamp. See that little purple square? That's our mic preamp. It's where the puny little mic signal gets amplified to line level.
See the arrows? Those indicate signal flow. It's flowing more like water than a real ac electrical signal since it's only flowing in one direction. So I worked some water in there any way.
(or dc like signal......). Why am I telling you this? I don't know. It doesn't matter. Let's move on!
At the mic preamp we have a gain knob to control the level of amplification. Little signal to bigger signal. From here our signal flows to the channel insert. The insert breaks our signal so that a sound altering device (see the compressor?) can be placed in the signal flow. The signal is 'sent' from the mic channel to the compressor input. It is 'returned' from the compressor output back to the mic channel. When a device is placed in the channel insert, all of the channel's signal passes thru the compressor.
Let's look up a bit further. See that red square. This is where the mic channel signal is split. We have the same signal continuing on up thru the rest of mic channel as the signal that's going to the pre fader send. Why is it called a pre fader send? Because the split is taking place before the channel's level fader. Since the split is occurring before the fader, no matter how high or low we set the channel level fader, the signal going to the pre fader send bus won't be affected. I hope that makes sense. If it doesn't, stare at it for a minute like one of those 3d images in the mall.
Or was that like 10 years ago?
Moving on! After the signal split, we have the channel level fader. I know, I know, it's a knob in the picture. Fader, knob, they do the same thing. I couldn't be troubled, or fit it in the picture, or draw one for crap..........pick the excuse you like best. So I think we all know what the channel level fader does.......it controls the level of signal that goes to the master bus where all our signals get summed, mixed, blended, however you like to visualize it. I'm calling it summed. An important thing to notice here is that not only does the channel level fader control the amount of signal that goes on to the master bus but it also controls the amount of signal that goes to the post fader bus. See the next split? It's after the channel fader. Think water and valves here if want to. So the post fader send bus is named so because? I hope you said because it comes after the fader. Other wise you aren't holding your mouth right. 3d puzzle........
Ok, so hopefully you understand the signal flow up to the pre fader and post fader send level knobs. If not, have a balowme samuch. From our send level knobs, the signal is routed to is routed to our reverb processors. We determine how much signal is sent to the processors with the send level knobs. Turn em to zero and nothing passes thru the send channels.....errr. I said channels. If we imagine our second mic channel being in the drawing, the word "channel" would be incorrect. When a channel has multiple inputs, it's called a bus. See how that works? Let me confuse you more. When a channel has two inputs, it's called a stereo channel. You can work this out. I have faith in you.
Why are the reverb processors placed in the sends and while the compressor is placed in the insert? I'm not explaining compression just yet but just know this. If the compressor is placed on a send bus, it's compressing a copy of the the mic channel signal. Look at the signal splits in the channel again. If we place the compressor on a send, we have one copy going to the master bus uncompressed and one copy going compressed. That's not illegal but for now we don't want to do that. We're using the compressor to tame the signal. It has to be directly in the signal path before any splits in the channel. The reverb processors don't need to be in the direct signal path from the channel to the master bus. Say we put a reverb in the insert. From the insert out on, all of the signal will have reverb on it. By placing the reverb in the send, we can go from zero to lost caveman with a twist of the knob and not affect the rest of the channel.
Ok, I forgot to label the send out level controls. You'll have to use your imagination there. Why do we have level controls for both the send in and send out? Think of the send out as the send bus master volume. With the mic channels individual send level knobs, we control how much of each signal goes to the effect bus. With the send out level knob, we control the overall effect volume that reaches the master bus.
We covered the whole mixer except the master bus. The master bus is where everything gets summed together. See that little blue square there? That's the spot where the all the signals from the mixer are mixed. Imagine a huge beer funnel. Ten guys are standing at the big end and each of them has a different brand of beer in his hand. At the little end of the funnel is Dogman with his mouth wide open, happier than Ralphy when he got his Red Rider bb gun on Christmas. Ten different beers in, one mixed beer out. If Dogman's mouth is the master bus input, you can imagine where the master bus output is.
Next will be............you pick. I'm thinking MIDI conroller setup and recording a MIDI track.