Getting to know (DAWs) Digital Audio Workstations Pt. 2 (Input Section)

In Part 1 of Getting to Know DAWs I briefly stated that the main components of a DAW are the pre-amps, audio converter units, and audio multi-track software, but I didn’t describe to you what they do! So in this post and all future posts for that matter, I will do my duty and describe to you all the technical terminology and explain the concepts behind the terminology so that you’ll gradually learn and acquire an understanding of the principles behind sound engineering.

But before we get started I want all of you to realize that the key to understanding how a digital audio workstation works is not necessarily all about the technical aspects, but more about the conceptual aspects of how a digital audio workstation operates.  For instance, if you understand how one channel strip on in a DAW works you will understand every sequential channel strip that is in that DAW. So without further ado let’s delve into getting to know digital audio workstations Pt. 2 (Input Section).

Input Section/Module – this is the first section/module that signal has to go through. Depending on the situation, the settings that you make in this module could make or break you. This is also the stage where analog to digital audio conversion takes place.  The terminology below is what can typically be found in the input section of any given digital audio workstation.

-    Phantom Power 48 V
-    Pads/Attenuation
-    Preamplifier
-    Mic/Line Switches
-    Trim

Phantom Power 48 V – is the option to change the voltage that runs to the microphone.  There are specific microphones that require phantom power, which is also known as 48 V. If for instance, the Phantom power switch is off and you’re using a microphone that requires phantom power you will not receive signal from that microphone. There are more specific voltages that are microphone specific. We will look into the specific differences in these microphones when we start talking about how microphones work and about microphone placement.

Pads/ Attenuation – this option almost speaks for itself. Attenuation or pads is the option to attenuate or rather cut the microphone signal, typically -20 to -30dB, before the signal enters the microphone preamp. This option is here for specific instances when something is coming in too hot (loud) so that it would result in the microphone preamp overloading.

Preamplifier (Preamp) – the preamp’s function is to amplify the low-level microphone inputs into a level loud enough to be modified and reproduced. This level is known as a line level, which typically is a +60dB boost from the low-level microphone input signal. A good example of a preamplifier outside of a DAW is on a guitar in the form of the pickup. Without a pickup the vibrations of the guitar strings wouldn’t be amplified resulting in the inability to hear the vibrations of the guitar strings at an audible level. This same principle is applied to any low-level input signal that comes in to a digital audio workstation.

Mic/Line Switches – as I stated before a preamp is used to amplify the low-level microphone signal into a line level signal. But, what if you already have a line level signal? And for that matter what if you put a line level signal into a microphone level preamp?

If you put a line level signal into a microphone level preamp, the line level signal would overdrive the microphone preamp. This is because the microphone level preamp is looking for a low-level microphone signal. So if you put a line level signal in a microphone level preamp it would essentially be amplifying a signal that does not need to be amplified. That is why we have the mic/line switch to identify what kind of signal is coming into the specified input.

Trim – adjusts a signal after it has gone through the preamp and/or line input to be compatible with other processes of the DAW. This should be tweaked so that when your faders are up all the way there is no audible distortion occurring.

This pretty much wraps up the input module of a digital audio workstation.  Now, depending on the size of the digital audio workstation there could be eight inputs or 32 inputs. This means that there might be 8 or 32 identical input modules lined up on a physical mixing board or on your computer screen. But now that you understand the basic workings of the input module, its nothing but 32 input modules lined up, right?

I’ll be posting “Getting to know (DAWs) Digital Audio Workstations” entries about each section (module) in DAWs until we have covered all their inner workings.

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