Sound Design and Audio Envelopes

In this chapter, you’ll learn the foundations of how sound works. We’ll learn what it is, how it’s manipulated, and how instruments create sounds. We’ll also discuss how to adjust the audio envelope of any sound sample. Once you understand how sound is created, you’ll be able to quickly learn about instrument plugins and have a basic idea of how they work.

In this chapter, we’ll explore the following topics:

• What is sound?
• What causes a note pitch?
• How do instruments create sound with different pitches?
• Why do different instruments playing the same pitch sound different?
• Manipulating audio sample envelopes
• Using Mod X and Mod Y for automation (using an automation clip in multiple places)

What is sound?

In the following chapters of this book, we will learn how to use plugins that manipulate sound. But what exactly is sound? When we talk about sound design, what exactly are we designing?

Sound is a form of energy like electricity and light. Sound is made when molecules vibrate and move in a wave pattern, which we call sound waves. Air is able to support many sound waves simultaneously. When you clap your hands, your clapping causes energy to move outward into the air.

The air molecules vibrate, bump into neighboring molecules, and transfer energy, causing them to vibrate. This energy gets dispersed outward from the source, around the room, and continues until the molecules’ energy is equally dispersed. The energy gets weaker as it gets distributed over a wider area. This is why there’s no sound in outer space; there are no air molecules vibrating to support sound waves.

Molecules don’t move around the room with sound. Instead, the energy...

What causes a note’s pitch?

When you think of pitch, you think about how high or low a sound feels. The pitch of a sound is determined by the frequency of the vibrations. Frequency is how many wave cycles pass through a given point per second. The more vibrations per second, the higher the frequency and the higher the pitch. The following figure shows an example of high and low frequency:

Figure 5.2 – Frequency

The higher frequency will have a higher pitch and the lower frequency will have a lower pitch. An example of a pitch is a middle C note, which has a frequency of 261.6 Hz.

Human ears can pick up frequencies between 20 and 20,000 Hz. Hertz (Hz) is the unit to measure how many wave cycles pass per second. As you get older, your ears lose the ability to pick up higher-pitch sounds. Sounds that are higher than this range are called ultrasonic. Sounds that are lower are called infrasonic. Some animals can hear sounds outside of this frequency range...

How do we hear things?

Sound causes air to expand and contract. Air expands under low pressure and compresses under high pressure. Changes in air pressure are useful because we can use devices to measure air pressure. Microphones detect changes in air pressure. Microphones are made up of a diaphragm stretched over a metal plate. As sound waves pass over it, the changes in high and low pressure cause the diaphragm to move back and forth and vibrate. This movement is measured by the device and converted into audio data. The data is then interpreted by your computer. The following figure shows an example of a microphone:

Figure 5.3 – Microphone

Your ears work in a similar fashion to a microphone. Your eardrums encounter air pressure changes, which cause them to vibrate. Your brain interprets these vibrations as sound.

When audio waves meet, they can react to one another. This can result in the following effects:

• Constructive interference is where two...

How do instruments create sound with different pitches?

In order to understand how instruments create pitches, we need to understand how instruments create sound waves. There are two types of sound waves. Traveling waves are observed when a wave is not confined to a given space. If you were to shake an unattached, loose rope, the resulting random ripple in the rope would be a traveling wave. The wave could have any wavelength as there’s nothing restricting the length.

Standing waves, on the other hand, occur when a wave is confined to a fixed space in a medium. The medium restricts the wavelength to hit recurring wavelengths and frequencies. If you were to shake a string that’s attached to a pole, the resulting constrained ripple would be a standing wave.

This medium restriction produces a regular wave pattern that repeats. We call this a standing wave (as though it were standing still). You can see an example of a standing wave in the following figure:

...

Why do different instruments playing the same pitch sound different?

Different instruments emphasize different harmonics/overtones. They emphasize some overtones louder than others. The waveforms of different instruments have different amplitudes, which also shape the sound. Also, remember that air is able to support many sound waves simultaneously. This variation in the combination of waveforms played simultaneously also shapes the sound we hear.

In our diagram examples, we’ve looked at sine waveforms. There are many kinds of waveforms. Instrument plugins can generate different types of waves, such as square waves, saw waves, and any sort of strange concoction developers can think up. The type of waveform will affect the resulting sound.

When you experiment with synthesizer plugin instruments, what the plugin is doing is creating different wave shapes. It adjusts the wavelength, amplitude, frequency, harmonics, and combination of waveforms it plays. Once the waveform...

Modifying sound envelopes

A sound envelope is a term describing how sound changes over time. When playing around with instrument plugins, you may come across the acronym ASDR. This stands for attack, sustain, decay, and release and refers to the four stages of a sound envelope.

The best way to understand a sound envelope is to modify one yourself:

1. Grab a single sound sample and load it up into the channel rack. Later on, after we’ve adjusted the sample envelope, we’ll add it to the playlist.

   I’m going to use an acoustic guitar sample, as shown in the following screenshot:

   Figure 5.9 – Guitar sample

   Note tha t I say channel rack, not playlist. It’s important that you don’t drag the sample directly into the playlist at this stage as you won’t be able to see the envelope controls.

2. Once loaded, left-click on the sample in the channel rack to bring up the sample properties. Select the envelope...

Using Mod X and Mod Y for automation

FL Studio provides you with control knobs that you can use to automate any other FL Studio plugin knob. Essentially, you can create an automation once and have control knobs on different plugins copy the automation.

Warning: this next feature is a little on the advanced side. If you find this confusing, don’t worry, as you’ll only need it when you want to create your own custom sound design.

In the same menu window as before, in Figure 5.10, you can see options for manipulating the envelope of Panning, Volume, Mod X, Mod Y, and Pitch. Just like the volume, you can adjust the envelopes for any of these parameters.

Panning determines whether you want the audio to come out of the right or left speaker. Pitch determines how high or low the sound is.

Mod stands for modulation. Mod X and Mod Y may seem a little unintuitive at first glance. From a big-picture understanding, X and Y are essentially placeholder...

Summary

In this chapter, we explored how sound works. We learned about sound waves, how we hear sounds, and how instruments create sounds. We learned about audio envelopes and how to adjust the audio envelope of any audio sample. With this information, you will be able to start using instrument plugins quickly and have an intuition of how they work. Finally, we learned how to link any FL Studio instrument plugin control to an automation clip.

In the next chapter, we will learn about music mixing techniques and explore plugin effects that can be applied to your sounds.