A StoryCorps signature interview, whether it’s on our Mobile Tour, in one of our StoryBooths in Chicago or Atlanta, or in another setting with a trained facilitator, offers a space for participants to share a part of their lives — and all starts with an audio setup that allows us to record a conversation before it’s later preserved in our archive at the American Folklife Center at the Library of Congress. Here’s the way a story makes its way from your voice to our audio software before it’s processed and made ready for publishing.
Below is a flowchart displaying the chain which sends the signal from the microphone that eventually ends up on one of our computers:
Our internal recording setup contains three microphones, two for our recording participants and and one for an engineer, should they need it. The microphones are held on boom arms, making them easy to maneuver and adjust, and are excellent for accurately capturing the sound of the human voice the way our ears perceive it, partially due to having a slight bump in higher-ranged frequencies on the sound spectrum.
When a StoryCorps participant speak into a microphone, the signal generated by their voice is carried down a cable, called an XLR, to our preamp/recorder. The signal generated by microphones tends to be fairly weak, so we use preamps to correct this. A microphone preamp takes the weak signal and adds more power to it, which allows it to travel with more strength and helps it sound richer and clearer.
We use condenser microphones, a type that are unique in that they require an external power source known as phantom power, provided by the preamp through the XLR cable. Phantom power supplies +48v of power to the microphone, allowing it to function, and it is important to make sure that this setting on our preamp stays on. In general, be careful when using phantom power, for if you disconnect the microphone or turn off the preamp before turning off the phantom, you risk damaging the equipment.
Our preamp/recorder also has a built-in memory card reader, which we at StoryCorps use as a backup copy of participant interviews to keep them safe. A best practice to go by is to always have at least two to three copies of your files backed up, in case one copy is deleted.
Before continuing down the main signal path, a copy of the signal is created and sent to a headphone amp. This is a small box which allows four pairs of headphones to listen to what is being recorded, before it has had any processing applied to it. This is rarely used, and is mainly for checking the quality of the audio.
After our preamp has boosted the microphone signal, the next step is to send it to an audio interface. Audio interfaces provide a midway point between the incoming signal and the computer by converting the signal into a format that the computer can interpret and process.
The interface also has a secondary output which sends the signal to a mixer. We use mixers to direct signal from multiple sources to our monitors (speakers) and headphones, and in this case, unprocessed audio from the mixer can be listened to again to check for quality, and to make sure the recording equipment is working while sitting in on the interview. We never keep speakers on at the same time, which would produce unwelcome extra noise in the recording and distract participants from telling their story.
After the mixer converts the boosted microphone signal, it is sent via USB cable to our computer, and fed into our digital audio workspace (DAW). There are many DAWs, but the one we primarily use at StoryCorps is ProTools. After recording, an engineer will use ProTools to edit the interview, and to refine the quality of the sound for the optimal listening experience. The engineer sends newly improved audio from ProTools to the mixer, so that they may listen to it through headphones or speakers. After this, they can decide whether there is anything more that needs to be done before exporting the final product from the software.