Effective Sound Effects
Using sound effects libraries to add spice to your music - as well as cover up problems.
By Chris and Trish Meyer | August 19, 2006
When start composing a song, I'm not interested in only the notes and beats; I'm even more interested in the mood I'll be creating. And as a person who relies heavily on loops to compose my music, I'm also interested in how I will set this piece apart from those others might create with the same core loops.
To help set a mood while adding an original flare, I regularly rely on a large sound effects (SFX) collection in addition to my normal sample CDs. I use these both as features of the final piece, and as band aids to cover up the bits I don't want a listener to hear.
When presented with the hundreds or thousands of sounds in a typical SFX library, it's easy to become overwhelmed. To make it easier to parse the sounds as well as what I might use them for, I typically group them into roughly four categories - hits, events, ambiences, and rhythmic sounds. Here are some ideas on how to use these various types of sounds in a composition.
Traditionally, sound effects come on audio CDs (see the sidebar Acquiring Effects at the end of the second page of this article), often with several sound effects in a single track - so you can't rely on the start or end of the track being the start ("head") or end ("tail") of the effect you want. Fortunately, most collections have pure silence separating the effects, so if you import the files straight off of CD, try the "remove silence" command available in most audio editing programs to automatically trim them up for you. Note that this doesn't always work, as the engineer creating the CDs might not have neatly trimmed off all of the background or tape noise off the front of effects, so you might still need to do some hand-cleaning - especially if you're trying to get tight timing at the head of a percussive sound.
Precise trimming is not as important with less percussive sounds such as ambience and events, as you will be timing some event in the middle of a sound to a beat, or just letting it run underneath a track. Indeed, it is all too easy accidentally trim too much away, resulting in a gated effect at the start or end (head or tail) of the effect. Err on the side of caution. To help out, some collections have a "1-pop" or "2-pop" built in: tones, beeps, or clicks that are precisely one or two seconds before the start of the actual sound. This reference makes it easier to trim sounds.
An imported track of a pair of metallic impacts. In this library (Sonic Boon's The Works), each effect is preceded by a "1-pop" which signifies the first effect starts exactly 1.000 seconds after the start of the tone; there is also a similar tone at the end of the track.
Now let's get into the fun bit - some ideas on how you might use these sounds…
Hits are usually short, percussive events, such as explosions, door slams, gunshots, anvil strikes, and the such. This class of sounds is the most obvious to use: Slide them to start on a downbeat in your audio composing or editing program. A good starting point is finding stand-ins for crash cymbals, such as big metal hits, explosions, and the such. They provide that extra "oomph" to reinforce the final downbeat, or to mark transitions to new sections.
Shorter events are also useful as kick or snare sounds. Try using them to punch up just some of the beats, such as the snare on the "4" - this gives you an A/B/A/C pattern, which is more interesting and compelling than the typical A/B/A/B kick/snare/kick/snare pattern.
Most libraries provide alternate versions of the same effect - for example, several similar but still different pop rivets or spot-weld snaps. It can be fun to map a few of these to adjacent keys and tap along with your rhythm to add another line to a percussion loop, adding human variation while setting it apart from anyone else who might use the same loop.
Events are longer than hits, and don't necessarily start or end percussively; they often have more of an envelope to them. They describe a self-contained action, such as a printer spitting out a page. These can be used a complex hits that are also triggered on downbeats or anywhere else you like.
My favorite types of events are what I call "whoosh-bang" sounds: those that build to a clear crescendo, preferably with a percussive event roughly in the middle to mark the start of the "bang." A musical example would be a cymbal roll into a crash; in the effects world, this may be a shell whizzing by and exploding when it hits its target, or a pneumatic press sliding down its rails until it impacts a piece of steel.
Drummers know how to maintain interest by adding rolls leading into downbeats, or through appropriate use of cymbals. Many loops - especially short ones, repeated - lack this drama and evolution. You can use whoosh-bang sounds to add this drama in yourself, such as to mark section breaks.
Above, a "whoosh-bang" style sound (from VideoHelper's Noise Generator) has been marked to show the start of the bang, which has then been spotted in ProTools to match up with the downbeat of a measure. In addition to providing a dramatic bridge between sections, this trick can also be used to cover up clunky edits or transitions.
The other great thing about whoosh-bangs is that they help cover less than ideal edits. This includes loop points that don't quite gel (such as a roll that doesn't lead into a crash, or a left over cymbal ring from a crash that was supposed to have happened in the previous measure), as well as transitions between dissimilar loops. I also use whoosh-bangs to cover overall edits in music, such as when I am trying to make a longer or shorter version of a live performance or previously-finished song.
Timing Whoosh-Bangs to the Beat
Using whoosh-bang style sound effects is a little less straightforward than simple hits, as your major synchronization point is somewhere in the middle, not at the start. First, identify this sync point: You can usually tell it from the peak in the waveform's height, plus a sudden change in the waveshape itself (indicating a change in sound from "whoosh" to "bang"). If you are editing digital audio, place a marker there, and slide the audio clip until that marker aligns with the target downbeat - many programs have automated functions to make this easier.
The start of the "bang" in whoosh-bang type sound effects can often be spotted by studying the audio waveform: Look for a peak or spike if the bang has a percussive start, as well as a change in the waveform's patterns as the sound transitions from whoosh to bang.
Synchronization is trickier if you are using a loop-based application, or are trying to trigger these sounds live to hit an upcoming downbeat. A solution is to turn it into a rhythmic phrase of its own. Identify your tempo, and calculate how long a measure is: Divide the tempo in bpm (beats per minute) by 60 seconds in a minute, and you have the length of one measure - 2 seconds, in the case of 120 bpm.
Let's say your whoosh-bang sound is 5 second long, with the "bang" hitting 1.5 seconds into the sound. In an audio editing application, you need to pad enough silence onto the head to fill out a one measure (or if necessary, an integer multiple of measures) before the bang; in this case, 2 - 1.5 = 0.5 seconds of silence.
To prevent loop applications from potentially stretching the sound, you also need to pad the tail to fill out one or more complete measures. In this case, we have 5 - 1.6 = 3.5 seconds from the bang marker until the end of the sound, which is longer than a 2 second measure - so we need to pad it out to two measures by adding another 0.5 seconds of silence onto the end. Now it's easy to drop into a loop slot in Live, Acid, or on a bar marker in a sequencer (or to trigger it with a MIDI note on a downbeat) and have it line up. Just remember to turn looping off, unless you want it to keep repeating!
If your application allows beat remapping and stretching, you can try remapping the beats so that a downbeat lines up with a bang, and then pad out the necessary extra time at the head and tail while keeping a somewhat normal pace during the sound effect itself. That's great in theory, but hard in practice, as some applications limit how much you can warp a beat. In general, being comfortable with a sample editing application such as Adobe Audition, Apple Soundtrack, or Sony Sound Forge is a good idea when working with sound effects.
Get articles like this in your inbox: Sign Up