There’s a lot to do to bring a field recording from concept to completion. There’s the extensive research needed to see if a session is possible. Calls made to line up talent. The actual recording follows, then detailed mastering, and meticulous curation.
Bewildered by it all? Unsure what each step requires? It’s understandable. I was recently asked to share guidelines for one of these stages: sound fx mastering.
Mastering itself is a fairly nuanced craft. Thousands of words could be written about it. Today’s article looks at the broad strokes: the important steps, the vital tasks, and what shouldn’t be skipped. Just learning about mastering? Want to review tracks you’ve already cleaned? This post is a quick checklist to help your mastering technique.
What Is Sound Effects Mastering?
Not every field recording is captured perfectly. Many need to be tweaked to before they are best experienced. This changing process is called sound effects mastering, or just mastering.
Sometimes the tweaks are minor, like trimming out a vocal identification at the beginning of a series of rock smashes. Others require time, patience, and sophisticated tools: think of stripping multiple buzzing frequencies and editing out dozens of recordist stomach gurgles from a late night urban atmosphere.
(Mastering field recordings is much different from the music mastering discipline, which focuses more on final technical balancing and preparing songs for different listening environments.)
An Approach to Sound FX Mastering
In general, what should a mastered field recording look like? It should be an audio recording that represents a single, evocative sonic idea without any technical errors.
That tackles two approaches: conceptual and technical. There’s a lot to be said about each approach. Let’s look at easiest ones to fix.
- Mastering choices.
- Naming and Labelling.
- Rendering and exporting.
This checklist can be used for both ambiences (atmospheric, environmental sounds), and specifics (focused effects like fans, mouse clicks, gunshots, a car passing).
Editing involves cutting and slicing a sound to keep the good parts, trim away the bad ones, and tweak the core sound.
- Isolate subjects. Field recordings require focus. They must depict a single “dominant” subject: a plane, a bird, wind, a park, a jungle montage, glass crashing, mortar fire, and so on. Mixed subjects – such a park with a plane flying above – won’t work and can’t be used in projects. Choose a single dominant subject and chop out other distracting sounds.
- Select evocative recordings. Choose the section that best represents the sound you’ve recorded: the three minutes of wind with the most tonal and kinetic howls and gusts, or the mortar fire with especially punchy, gut-lurching booms. Avoid sprawling ambiences or uninspired specific effect performances.
- Remove problem sounds. Edit away recordist moves, breaths, clothing rustles, and footsteps. Slice out microphone bumps, cable rattling, and mic stand wobbles.
- Delete wind. Remove wind from the recording. Avoid attempting to EQ ambiences; this rarely works and it typically sucks the substance out of any atmosphere.
- Check crossfades. Ensure that fades that join sections of sound are smooth. The edit point beneath the fade should not be discernible.
- Add fades. Add brief fades (i.e., less than 1 second) the beginning and end of atmospheres to ensure they do not pop from severed waveforms. Customize fade slopes for specific effects. For example, metal dropping may need a quick fade in and a prolonged fade out while metal pieces settle into stillness.
Processing involves using plug-ins or other tools to enhance or fix the sound that remains after editing.
- Balance the stereo image. In most cases, stereo field recordings should appear balanced in the ear with levels relatively similar for left and right channels.
- Normalize the sound. Adjust the level for field recordings proportionally so they reflect real-world loudness: gunshots will be louder than rush hour traffic, which will be greater than beach waves, which will have more presence than a room tone or people whispering. Multimedia sound effects (e.g., whooshes, UI alerts, buttons) are generally presented loudly.
- De-clip. Use a de-clipping plug-in to repair peaked, distorted sounds.
- Hum removal. Diminish whine, HVAC tones, and fluorescent light buzzes with a hum removal plug-in.
- De-click. De-clicking plug-ins can quickly repair line pops and static clicks.
- Reduce rumble. Urban rumble can submerge a field recording in low-frequency energy. Use a high-pass filter below roughly 100 Hz to “roll off” these tones. Do this with care; ensure the heft of the recording isn’t reduced.
- Equalization. EQ can be used to notch away isolated frequencies of sound, tame swaths of hissy high-end, or diminish thick and muddy mids. Much of this is subjective, and takes a lot of experimentation and a trained ear for a satisfying result. Use with care. In general, follow this rule: start with notching and follow with shelfs and high- and low- passes later for best results.
There are other tools for repairing audio. For beginners, focus only on the ones listed above. These restoration tools are difficult to screw up. Others such as noise reduction and spectral repair can do more damage than fix things when used by an untrained ear. Save those advanced steps for later in your career.
While the previous guidelines hold for the vast majority of field recordings, this checklist depends on your audience. Find out which your fans prefer and choose the option that helps them the most.
- Ambience length. Aim for a length of no more than 3:30 for environmental sounds. Recorded longer? Choose the best, most evocative 3:30 from the whole.
- File organization. Do you have a dozen Tibetan gong hits? Choose between individual takes that present each hit in their own file, or collated files (thanks René) that gather them all in one take, separated by a few seconds.
- Level. Some fans prefer sounds louder so they can hear and select them easier. Others want final levels set lower, relative to the projects they work on.
- Looping files. Get extra milage out of your sound effects by providing an additional seamlessly looping file.
Naming and Labelling
- Naming. Compose a final field recording name using simple, human-readable language.
- Complete names. Describe both what the sound is (i.e., the noun), and what it is doing (i.e., the verb).
- Evocative words. Use strong verbs, nouns, adjectives, and adverbs. These make discovering field recordings easier, and more appealing for selecting them.
- Avoid useless words. Don’t add a catalog number, sound library name, sampling rate, microphone, or so on to the file name. That makes reading and understanding field recordings difficult and cumbersome. Add that info to metadata instead.
- Spelling and grammar. Spell- and grammar-check your names before committing.
Exporting and Rendering
- Interleaved files. Export final multichannel files as interleaved files.
- Preserve sampling rate. Keep field recordings at the same bit-rate and sampling rate as they were recorded. Don’t upsample to higher sampling rates.
- Sampling rate selection. Field recordings are typically mastered at 96 kHz, 24-bit. Use higher sampling rates only for clips you know will be processed or used in sound design.
Changing Field Recordings
Of course, much more can be done while mastering sound effects. There are many others ways you can tweak and edit field recordings. This checklist will help anyone prepare the vast majority of field recordings well and solve most problems.
- An Introduction to Mastering Sound Effects.
- 2 Techniques for Setting Sound Effects Library Mastering Levels.
- Common Mistakes and How to Fix Them: Sound FX Curation.
- Five Reasons Why A Sound Effect’s Name is Vital.
- 15 Tips for Naming Sound Effects.