Treble, Bass, and EQ

Audio is created by audio waves at different frequencies. Some of them are low in pitch, like Barry White talking or the pounding of a large, deep drum. These are referred to as bass tones. Some of them are high in pitch, like little children singing or the shrill violin notes from the shower scene in Psycho. These tones are generically referred to as treble tones. The range of tones between treble and bass is often referred to as the mids, short for the middle of the range.

Dry and Wet Out

When applying an audio effect to a piece of audio, it’s common to use the analogy that we are wetting it; soaking it in effects. So, the audio track on its own is said to be dry. Most audio effects, including several in After Effects, allow you to balance the final mix between the original audio signal, and the audio signal with the effect applied. The original audio signal coming out of the effect is referred to as the “Dry Out”, and the effected audio signal coming out of the effect is referred to as “Wet Out.” Think of this like the audio equivalent of opacity. To lower the volume of an applied effect, reduce the Wet Out property, if there is one.

If you’ve applied an audio effect (such as Backwards) that doesn’t have such controls, you can duplicate the audio track and apply the effect to the duplicate, and then balance the Audio Levels property of both layers to achieve the desired balance. If you’re applying this effect to the audio on a layer with video, you can duplicate the layer and turn off the visibility of the duplicate.

Left and Right Stereo Channels

Another audio attribute that consistently comes up is that of stereo audio. This refers to audio played in the left channel (or speaker) and in the right channel (or speaker). When an audio clip plays back the exact same audio in both ears, the clip is said to be mono. Most elements in musical recording have some degree of panning applied. Panning is the process of spreading out a sound between the left and right channels. Each instrument can be completely in the left or right channel, or be perfectly mixed between them, or it can be panned to be in one channel more than the others. Having a good stereo mix gives audio tracks a greater degree of realism, as objects in the real world create sounds all around us.

The Backwards Effect

The Backwards effect causes audio tracks to be played backwards. This has the similar sound to grabbing an LP record that is playing, and manually dragging it backwards. This is great for sound effects. Audio clips of snare drums or cymbal crashes with the Backwards effect applied create sweeping swooshes that are great accents for motion graphic elements. There are no properties for the Backwards effect, other than to select Swap Channels, which trades the left channel for the right channel.

The Bass & Treble Effect

The Bass & Treble effect is another very simple audio effect. There are only two parameters: Bass and Treble. You can increase or reduce the volume of low tones using the Bass property. Independently, you can also increase or reduce the volume of high tones using the Treble property. The Parametric EQ effect in this category gives you much more control, but if you’re new to working with audio, this effect may be simple enough for you to make the adjustments you need.

The Delay Effect

The Delay effect is a little more complex than what we’ve looked at so far. The Delay effect creates a repeat of the audio in an audio layer. This effect is useful for creating echoes, or for creating the illusion that audio was recorded in a large, cavernous environment. For a slight audio delay, as if you were talking in a large cathedral for example, it’s probably better to use the Reverb effect, discussed later in this chapter.

The Delay Time value determines—in milliseconds—how long the delay is from the original signal. The Delay Amount value determines how loud the first echo is compared to the original signal. The default value of 50% creates an echo that starts off being half as loud as the original audio. Increasing the Feedback property allows some of the echoes to create more echoes. If this get too chaotic, you can reduce this value to create a cleaner delay.

The Flange & Chorus Effect

Flange and chorus are two effects common in the audio world. Although they are different effects, they are created in a similar manner, and so we have access to them both in the Flange & Chorus effect. Both effects are created by creating a slight delay in the audio signal, and duplicating that delay several times. These echoes are referred to as “voices” in this effect.

Flange effects are created by modulating (adjusting) the echo, which usually results in a warbled effect, as if you were a cartoon character saying something underwater. The warbled echo can also be slow and smoother, like the bridge on the Lenny Kravitz song, Are You Gonna Go My Way. Chorus is usually a more subtle effect, with the delay only slightly out of phase (usually), which sounds like the audio is being created by multiple sources. You can hear a similar effect in the vocals of songs by The Ramones.

The Voice Separation Time value determines the delay between echoes. Use the Voices value to determine how many echoes are created. The Modulation Rate parameter controls the speed of the warble, while the Modulation Depth controls how much warbling is happening.

If you wanted to create a flange effect with a quick warble (like you were underwater or gargling), try taking up the Modulation Rate value to something like 2 (which creates a faster modulation, or warble), and increase the Modulation Depth value to about 65% (which creates a more intense modulation). To slow the modulation, reduce the Modulation Rate property.

If you wanted to create a chorus-type effect, the first step is to increase the Voices parameter, and then to enable the Stereo Voices checkbox. Selecting Stereo Voices will stagger the voices in each speaker. So, the first voice will play back in the left speaker, the second voice will play back in the right speaker, the third voice in the left speaker, and so on. This goes a long way into creating a realistic chorus effect. Next, I will increase the Voice Separation Time to about 10, then increase the Voices value to about 4, leave Modulation Rate at its default, leave Modulation Depth at its default, and take the Voice Phase Change property to about 90%. This will create a rich chorus effect. Of course, these are just some sample settings. There are many other formulas for creating flange and chorus sounds in the Help, but these are some settings to get you started experimenting with this effect.

The High-Low Pass Effect

The High-Low Pass effect is like a tone filter. It has two modes: high pass and low pass. High pass filters out low (bass) tones, and allows high (treble) tones to pass through. Low pass filters out high tones and allows low bass tones to pass through. The Cutoff Frequency property allows you to fine tune exactly which tones get filtered out, depending on which mode you’ve selected from the Filter Options drop down.

The High-Low Pass effect is especially good for audio recorded with video. Many times after recording, you might hear a low pitched hum from a generator, or maybe a high-pitched whine from a fan or other device. The High-Low Pass is a great way to eliminate such noise from your audio.

High and Low Pass filters are really helpful in creating realism in sounds. For example, if you had a stock sound effect of the ambience in a night club scene, you might want to apply a low pass filter (by choosing Low Pass from the Filter Options drop down) if the shot takes place outside of the club. If the shot then moves inside of the club, you could animate the Cutoff Frequency property to go from lower to higher. Adding a little Low Pass (and maybe a little High Pass in a separate, additional instance of the effect), can also make sound effects that were recorded close to a microphone (like foley effects) sound like they actually exist in an environment.

The Modulator Effect

The Modulator effect creates an end result similar to flange, but without the additional voices. Without the additional voices, the modulation to audio tone in this effect can create effects ranging from a vibrato, to a more intense tremolo. These effects are reminiscent of the “speed” setting on vintage guitar amplifiers. The important settings in this effect are ones that we’ve already discussed in the section in this chapter on the Flange & Chorus effect: Modulation Rate (the speed of the modulation) and Modulation Depth (the amount of modulation).

The Parametric EQ Effect

Effects like bass and treble allow you to adjust high and low tones. But what about all the tones in between? And what if there are certain frequencies of the high tones that you want to make louder, and other high frequencies that you want to make quieter? The Parametric EQ effect allows you more control over individual audio frequencies using three different sets, or bands.

Each band gives you precise control over an exact audio frequency. You can adjust up to three bands. To enable a band, select one of the Band checkboxes in the Effect Controls panel. Each band has the same three controls. Frequency specifies which audio frequency you are targeting for that band. The Bandwidth value is almost like feathering the selection. You might want to, say, enhance the volume of the snare drum. You might not know its exact audio frequency. Use the Frequency parameter to make your best guess. Then increase the Bandwidth value to increase the range of values that the band affects. Then, use the Boost/Cut value to increase or decrease the volume of the chosen frequency. The Parametric EQ effect allows you more control over your audio adjustments.

Figure 3.1 The Parametric EQ effect in the Effect Controls panel. Each color represents a different band.

The Reverb Effect

The Reverb effect is one of the most frequently used audio effects in the history of ever, as Spongebob would say. If you’ve ever heard a song recorded in a recording studio or watched a TV commercial or seen a movie, you’ve heard an artificially added reverb effect. The purpose of the Reverb effect is to add a slight echo, usually to make audio sound more like it does in real life. In real life, when you speak or play an instrument, the acoustics of the environment (such as walls, or the ceiling) bounce the sound around creating a fullness. Reverb adds that fullness to audio that sounds flat.

The echo added by the Reverb effect is usually much more subtle than the echoes created by the Delay effect. You might think of it this way: If you want the effect to be obvious, use delay. If you want the effect to be imperceptible, use reverb.

The Reverb Time value determines the time (in milliseconds) between the original audio and the echo. Increasing the Diffusion value can create the illusion that the audio was created in a large room. Decay determines how long it takes the echo to fade out. If the sounds takes longer to fade away (which is created by a high Decay value), then it indicates that there is more space in the room. So, a larger Decay value is better for simulating audio in a large space. Brightness refers to the treble values in the echoes. Increase the Brightness value to brighten the reverberating sound.

Reverb is a great effect for blending audio. In the same way that we adjust color to aid in compositing when combining visual elements, it’s important to make sure that audio tracks that are supposed to exist in the same scene have the same amount of reverb. This is particularly important when using overdubs from actors in movies.

The Stereo Mixer Effect

The Stereo Mixer effect is the tool to use if you need control over the channels in a piece of audio. This effect gives you control over the volume (level) of the left and right channel independently. Because this effect allows you to adjust volume in terms of percent (instead of by decibels, as in the Timeline panel), it might be more intuitive for audio amateurs to use this effect for basic audio adjustments.

The Stereo Mixer effect also allows you to change the panning for each channel. If you’re experiencing any weird audio anomalies because of this effect, you can probably fix it by enabling the Invert Phase checkbox, which ensures that the redistributed audio frequencies don’t clash with each other.

The Left Pan control controls what is happening with sound that is panned to the left (similar to the Right Pan panned to the right). By default, Left Pan is panned to –100%, which is all the way left. Right Pan is a positive 100%, which is all the way right. Note that these properties can be animated. To animate the sound of a helicopter going from left to right through a scene for example, you might take the Right Pan value down to 0 (which centers the balance of the right channel), or even all the way down to –100% (which takes the content of the right channel and places it all the way to the left in the stereo spectrum). You can then animate the Left Pan and Right Pan values to be positive later on in the composition. This will cause the sound to go from left to right, creating the illusion that sound is traveling from left to right. Little touches like this can really sell a shot.

The Tone Effect

The Tone effect generates audio tones. It actually makes sounds from scratch. The Tone effect is the only effect in the Audio effect category that does so. You can even apply this effect to a solid layer to create audio on it.

Figure 3.2 The Tone effect in the Effect Controls panel.

The problem with the Tone effect is that it’s almost impossible to use. You can select an exact frequency to be played by five different frequency generators in this effect. If you know music and audio frequencies well, you can set these to play a chord. But honestly, it would probably be easier (and faster) to walk away from your computer, learn to play a musical instrument, go to a recording studio, and record yourself playing that chord, than it would be to get the Tone effect to play it correctly. I’m only slightly exaggerating.

So why use it? I actually do use this effect on occasion. Sometimes, I’ll have issues playing back audio. I’ll apply the Tone effect to a new solid in a new comp to see if the problem is with the audio I’ve imported, or with my audio hardware configuration preferences.

The great benefit to this effect is that Adobe has included some great animation presets for this effect. You can access these from Adobe Bridge, or from the Animation Presets drop down at the top of the Effect Controls panel. Figure 3.3 shows the list of included presets. The presets are mostly phone related, including a dial tone, dialing, and a busy signal. There’s also a sweet laser blaster.

And if you ever needed a quick retro laser blast or “fail” tone, just take the Waveform options drop down to Square, zero out each frequency from 2 to 5, and take Frequency 1 down to about 80. Make it a short pulse by animating the Level parameter from whatever volume you want, down to 0. It sounds like an old Atari game from right inside After Effects!

Figure 3.3 The animation presets for the Tone effect that are included with After Effects.