swrs: Recording Sound (audio)

Now that we understand that sound is created by vibrations in the air, it’s time to get into how we capture those vibrations and play them back. Recording or capturing audio in a Digital Audio Workstation (DAW) such as Pro Tools or Cubase is a process that can be broken down into steps. Let’s use a snare drum hit as our example.

Step 1: A drummer strikes his snare drum and sound vibrations are sent into the air.

Step 2: The sound vibrations from the snare are picked up by a microphone and converted into an electrical signal. Microphones (and speakers) are also called transducers for this reason. Transducers convert energy into signal and signal into energy.

Step 3: The electric signal travels through an XLR cable (microphone cable) and into an interface where it is converted once again. Interfaces, such as Steinberg’s UR22 and Focusrite’s Scarlett 2i4, act as multifunctional sound cards for your computer. They convert the electrical signal into digital information, and they convert digital information back into electrical signal.

*Your interface will become the hub for your monitor speakers and headphones, as well as the first gain stage for your audio. It contains your microphone preamps.

Step 4: The digital information appears on the computer screen within its corresponding audio track in whatever DAW you’re using. If your microphone cable is plugged into input one on your interface, then it can be recorded onto whatever tracks have input 1 selected as their audio source. The snare hit will be represented visually as a complex sound wave.

*Steps 1 through 4 occur immediately as the snare is struck. 

Step 5: After recording the snare hit, you can then edit, route, add effects, and play it back from your DAW. Playback is the exact reverse process from recording. First your computer sends the digital information into your interface where it is converted back into an electrical signal. From there it is sent out across speaker cables and into your monitor speakers and/or headphones which act as transducers, and convert that signal back into vibrations that our ears pick up.

 

Terms

Audio Track: A track within a DAW that is used for recording and manipulating audio.

DAW (digital audio workstation): A DAW is an electronic tool used for recording, editing, and producing audio files. They simulate a recording studio within your computer. The DAWs that we will be dealing with refer to computer programs such as Pro Tools, Cubase, Logic, Ableton, and Garage Band.

Gain Stage: An amplification point within a signals path. An increase or amplification in signal strength results in louder signal on our end. A decrease in signal strength results in a quitter signal. In recording we must keep an eye on signal levels, mainly to keep fairly matched, and to keep them from getting too loud or “hot”.

Interface: A piece of hardware that plugs into your computer and expands its sonic capabilities, acting as a highly functional sound card. It allows you to connect professional microphones and instruments for recording into the computer. It also has the outputs for your headphones and studio monitor speakers, as well as additional outputs for connecting to additional gear. Examples of audio interfaces include Steinberg’s UR22, Universal Audio’s Apollo Quad, Focusrite’s Scarlett 2i4, and RME’s Babyface.

Monitor Speakers: The studio speakers that you are using to mix. Although the term also refers to the speakers or headphones that performers use to hear themselves.

Preamp (preamplifier): amplifies weak audio signals, like that from a microphone or pickup. Think of it as your first gain stage in audio recording.

*In home recording many gain stages are simulated within the DAW. That is to say that no actual amplifiers are involved outside of the preamp and speaker/headphone volume.