For Voice Over Non-Nerds (OK, Nerds, Too):
Tech Terms To Understand About Audio Recording
By James Romick
Voice Actor, Voice Over & Audiobook Recording Instructor
In the process of doing research for this article, I came across a website that lists (alphabetically) all of the terms and nomenclature pertaining to audio recording you'd ever want (or care) to know, all cross referenced with links to links with their own links to all possible synonyms and associated slang terms and on and on and on.
You can (as I did) spend hours and hours clicking your way down the rabbit hole of audio recording terms and terminology until that pork chop you had frying on the stove starts to burn, setting off the smoke alarm, causing your dogs (I have three) to go into the barking jag of their lives, finally snapping you out of your trance.
Here's the link. Have fun, but don't leave anything on the stove before you click on it: https://lossenderosstudio.com/glossary.php?index=a
"So," I thought to myself, "what things should I mention that your average non-nerd (or nerdy) voice artist should know so as not to be embarrassed, without dumbing the article down and/or appear to be condescending?"
Well, here are some basics.
ANALOG VS. DIGITAL
When studios recorded on magnetic tape (which still happens, by the way), that was an Analog Recording.
Sound waves from your voice hit the microphone, were converted into electric impulses that were sent through a series of wires to the record head of the tape machine where the metallic bits embedded in the magnetic tape were aligned in such a way that could be nearly identically be replicated upon playback.
Editing consisted of cutting that tape on an angle with a razor blade when placed in a "splicing block" and then placing a thin, industrial strength piece of sticky tape on the underside.
Fast forward to today.
Digital Recording slices up that Analog signal via an A/D (Analog to Digital) converter (via a preamp/interface connected to the microphone and to the computer) into the 1's and 0's that your DAW (Digital Audio Workstation – the software) and computer understands.
On playback, the process is reversed through a D/A (Digital to Analog) converter back into something that humans can actually hear and make sense of.
DAWs perform editing in fundamentally two different ways, destructive and non-destructive, which will be covered in a later article.
Either way though, digital sound editing is sooooo much easier and more precise than splicing up and piecing together analog magnetic tape.
PREAMP VS INTERFACE
These two terms are most often used interchangeably now-a-days. But they are two different things – kinda.
A Preamp (or preamplifier) is a piece of hardware that amplifies (or "boosts") low-level audio signals.
An Interface (which has a built-in preamp) is in the signal chain between the microphone (via an XLR cable) and the computer.
The preamp/interface connects to and draws power from the computer via a USB connection. And in so doing, provides 48v Phantom Power to a large diaphragm condenser-type microphone.
Dynamic Microphones, which are mostly used for live performance and public address systems and are not recommended strictly for voice over, require a lot of "gain" but do not draw phantom power from the interface. In fact, phantom power could very well ruin a dynamic mic.
That gain/signal boost may come from another piece of apparatus. One such name brand is called a Cloudlifter.
USB Microphones, which connect directly to the computer via a USB cable, have the preamp built into it. Thus, there is no need for a separate interface.
POTs, PANs, PADs, PEAKS & PEGGING
A POT (potentiometer) is a device used to adjust different aspects of the audio signal such as volume, balance and tone. They are typically either knobs or sliders.
A POT can be used to PAN left or right.
A PAD can be a POT, switch or plugin used to attenuate (reduce the loudness) of the incoming signal to prevent the Peaks (the highest point in the waveform) from Pegging in to the Red (clipping the signal into distortion).
FX, VSTs, AUs & PLUGINS
FX ... no, this is not the cable channel.
FX (or processing effects) are things added to the recording (usually in the post-production/mastering phase) such as noise reduction (NR), noise gate (GATE), reverberation (REVERB), equalization (EQ), compression (COMP), expander (EXP), limiter (LIM), etc.
Some of these you will need and use, others not so much, and a few that you absolutely should not.
The order in which these are placed (which is very important) is called an FX Chain or Rack.
VST (pictured) stands for Virtual Studio Technology. This is the software equivalent of the physical hardware components you would see in a Rack in a recording studio.
AU (Audio Units) was developed by Apple. These are like VSTs, but can only be used with DAWs on a Mac that accept their use. Most DAWs do, some do not. And some 3rd party AUs are also available as VSTs.
And these are all considered Plugins.
HP, LP, BAND & NOTCH
These refer to EQ. In the diagram:
1. HP = High Pass Filter.
2. BAND = Band.
3. NOTCH = well, Notch.
4. LP = Low Pass Filter.
The pass part is what the filter lets through.
For instance: Say that you set the HP filter at 80Hz (more on that later). Then all of the frequencies above 80Hz will pass through and be heard. Whereas those frequencies below 80Hz will be attenuated (dropped in volume), depending upon the slope (how severe the cut) is applied – usually designated as dB/octave.
An HP filter and a LC (Low Cut) filter are the same thing, also often called a Roll Off filter.
Band Pass filters boost or attenuate a wide or narrow band of frequencies called the Q – like boosting or softening the bass frequencies on your stereo or radio.
A Notch filter concentrates around a very narrow band of frequencies centered around a specific frequency and attenuates or boosts them. Notch filters will often be used as a De-esser to soften sharp sibilant S sounds.
dB, RMS, LUFS, VU
These all refer to loudness.
A decibel (dB) or decibel Full Scale (dBFS) is defined as:
What does that mean? Who knows, really.
What is important is that 0.0dBFS is the absolute maximum voltage (power) that an A/D converter will allow before clipping (distortion).
Most often you see recommendations not to exceed -3.0dB peak for VO. That spec leaves some "head room" (or "buffer") so you won't even approach distortion.
The logarithmic part means that the levels are exponential rather than linear. That means that -3dB is not twice as loud as -6dB, but exponentially louder.
RMS (Root Mean Square) is measurement of average loudness (louder passages and softer passages) over time.
Audiobooks, for example, attempt to have the average listening RMS levels of between -18dB and -23dB, so that whispers and shouts can be heard and understood without having to manually raise or lower the volume. That could get really tedious!
LUFS (Loudness Units Full Scale) is similar to RMS and pertains more to the broadcast industry. The sound specs for podcasts and YouTube videos, for example, are measured in LUFS.
VU (Volume Unit) is the measure of loudness response of the human ear. The VU Meter was developed in the United States in the late 1930s as visual representation of this measurement.
AMPLITUDE, FREQUENCY, WAVELENGTH
Amplitude is the dynamic range in loudness of sound waves. Huh! There's no fun abbreviation for this one.
Frequency (Cycles/Second or Hertz) is the measurement of a wave from peak to peak over time. Broadly speaking, the higher the number, the higher the "pitch" of the sound.
This one does have a fun abbreviation. Hz. The range of human hearing is between 20Hz to 20KHz. Although as we get older, we lose more and more of that upper range and we may also qualify for Senior Citizen discounts.
Wavelength is the distance between wave peaks.
AND MORE ...
Bass Traps. These are typically wedges of acoustical foam placed in corners to prevent low frequency reflections and standing waves.
Pickup Pattern (Polar Pattern). This is how the microphone's capsule directionally receives the sound. There are many different types of Pickup Patterns. But the most common one for VO is the Cardioid (heart shaped) pickup pattern.
Frequency Response. This is a chart or graphic representation showing how a microphone capsule reacts to the range of frequencies that humans can hear ...
Well, I think I have exceeded my allotment of words for this article. So, I guess we will have to continue this at another time.
Until then, happy recording.
James Romick figures he's in the fourth or fifth phase of a 40+ year acting career, who "never in my wildest imagination did I ever think that I'd be recording and producing audiobooks at home in my den from a vocal booth I designed and built myself." In between acting jobs, James also studied audio engineering at the Institute of Audio Research in NYC at a time when editing analog tape in a "splicing block" with a razor blade was the norm. "Digital recording and editing is soooo much easier!" James has several DAWs (7 or 8 by last count) installed on his computer and has played around with them all. But he keeps coming back to REAPER as his go-to. James offers one-on-one consulting via Zoom and Skype on how to set up REAPER specifically for voice over and audiobook production. James also offers tutoring in voice over and audiobook recording. He has given PowerPoint presentations on basic home studio setup, REAPER and audiobooks at the SAG-AFTRA Foundation (EIF) Voiceover Lab in New York City.
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