Mixing #4: The Mixer Part 3

Understanding signal flow is something that you will find to be essentially valuable over the years. The way in which the signal travels through the mixer has very critical impact on its overall sound. In a DAW you have numerous options as to how the signal can be processed from start to finish. In this article we will begin exploring Busing/Routing. You can send or route the signal for processing in more way than you can imagine. Before we dive into that, let’s briefly ties some information together from the last 2 articles to further our understanding of the signal flow! Let’s go!

Signal Flow

Now that you understand more about the way sound enters and travels within your mixer’s channel strip, let’s put it all together. Listed below is how the signal flows (in order) from the source to your tracks output:

Vocal/Instrument(s) > Audio Input > Insert > Send Pre-Fader > Solo & Mute > Track Fader (volume) >

Send Post-Fader > Pan Control > Track Output >

Vocal/Instruments: Your sound actually begins here. Your microphone goes into the Mic Input. Your other instruments can go into the Mic/Line, or Guitar Input. These are all located on your audio interface.
Input/Source Audio: This is where the signal that comes from your hardware interface input or from the one recorded to your computer’s hard drive begins. From here the signal enters the channel strip.
Insert: The insert function allows you to place effect processors onto the track. These processors include equalizers and dynamics processors. The effects that you place here are tools used to change the sound of the signal entirely. Your DAW comes with these tools in the form of what we call stock plug-ins. Some DAWs have these processors built onto the channel strip while others do not. In addition to these, some systems may use both the insert as well as processors built onto the strip.
Send Pre-Fader: This is where a portion of your signal can be routed to an Aux bus. On that Aux bus you can insert an effect such as Reverb or a Delay. When the Pre-Fader (Pre) button is turned on, it bypasses the actual track or channel fader of the signal.
Solo & Mute: Pressing the solo button silences all other tracks except for the selected one. Pressing the mute button silences only the selected track.
Track Fader: This control allows you to adjust the volume level of the signal as it exits the track through its selected output.
Send Post-Fader: When the pre-fader (Pre) button is turned off your signal is being sent to the effect after it flows through the signal’s track fader. Adjustments made to the track’s volume are also applied the Send function.
Pan: The panning knob/slider allows you to control how much of your signal will be placed to the left or right in the stereo field.
Output: This is where the signal leaves you track. The output you select here is the place your signal will travel to next. For example if you select “Master” as the track’s output, then the signal flowing through it will go to the master bus.

I hope that things are coming together for you. Now that we’ve gone over signal flow into the mixer and channel strip, let’s go a little further to get an understanding of where a signal may flow after leaving a tracks output.

Routing

Once you have all of your instruments going into the mixer, you have to route them somewhere. Routing is when you send your signal somewhere within the mix. The place your signal ends up is called a bus. This is also referred to as busing. After leaving the channel strip a signal may be routed through multiple buses before reaching it final destination. However, this may vary depended on the track. Here are a few places that the signal may be routed to.

Auxiliary Bus: This is where effects can be placed to add to the signal. An aux bus is used when you are using one of the Send functions on your channel strip. nIn many systems the aux bus has its own channel. The effect you choose will be placed one of its inserts. The output of this track can be routed to a sub mix or the master bus where it will be mixed with all of your other tracks.
Sub Mix Bus: A submix bus is where you can mix a group of tracks at once before they are flow to the master bus. For example you may have a group of instruments like some guitars or drums that you want to control separately from the master fader. When you route output of each of those tracks into the input of another track and sub-mix them there, you can then control overall volume of the group independently of any instruments not assigned to that channel. Here you can also process them together on the sub-mixes channel strip. In DAWs like Pro Tools you can set up a sub-mix using an Aux track. Instead of sending a portion of the signals to the aux, you route them directly into the aux’s input selecting one of its many internal buses.
Master Bus: All of your individual tracks and sub-mixes end up at the master bus. The faders for each channel on your mixer control how much volume for each channel is sent to the master bus. The master bus’s channel strip looks different from the others having inserts but no send function, solo, or mute buttons. This is because the master bus is the last stage of all on your mixer these functions are unnecessary. This is final stage of all signal flow and where your music is mixed. Using the master bus inserts you can process the music as a whole. I suggest caution here when it comes to processing! Taking this approach without some direction can have a devastating effect on your music. This is also where you select which hardware outputs your stereo mix will go to. The master fader controls the overall volume of all the channels routed to it as well as the volume level sent out to your speakers/monitors.

After reaching the master bus a hardware output must be selected in order for the music to be heard during playback. The same signal that is sent from the master bus output travels back to you hardware audio device such as an interface. Let’s briefly take a look at where this signal goes on its way back to our ears.

Master Out Jack: The signal passed through this jack on its way either to your speakers’ power amp or directly to a set of powered monitors. Both the master fader on your DAW’s mixer and the master volume on your interface control the level of the signal passing through the master out jack.
Monitors Jack: This jack basically gives you another place to plug-in more speakers or headphones. On some computer-based interfaces this function can be used with the simple turn of a dial labeled “monitor mix” without the use of additional speakers. This is called for “hardware monitoring” and it comes in handy during times recording by allowing you to monitor directly from your interface. The good thing is that it reducing the latency that you commonly hear while listening to yourself record.
Phones Jack: This jack is for your headphones and can be controlled by the phones knob on you master console or interface. The volume here is controlled separately from the master out and monitor jacks though it receives the same signal from the master bus.

With today’s ever increasingly sophisticated technology, we have so much at our disposal with just the simple click of a mouse. Our audio interfaces are generally highly versatile regardless of cost and they really simplify matters that would call for more equipment and of course that means more money. No matter what you are working with if it ain’t broke you can grow. Learning these things really helps to give you a solid foundation to build your mixing skills on!

Well, that’s all for this article. I really hope that you are understanding the mixer and how the signal enters, flows through, and leaves the it. You are welcome to go back and read the other articles again, take notes, whatever it takes. With all your getting, be sure to get an understanding. A balance of study, application, and endurance on your journey guarantees a reward. There is only more joy in learning ahead and I’m excited about your growing with you! If this article helped you out, please share and comment below. I’d love to hear from you, so feel free to ask any questions. I thanks for your time. The Most High Bless you! Shalom!