What is a Sound Envelope? 4 Parts ADSR

You may have heard the term “sound envelope” before, but what does it actually mean? A sound envelope is a graphical representation of the amplitude and time course of a signal. In other words, it’s a way to visualize how a sound changes over time. There are four main parts to a sound envelope: Attack, Decay, Sustain, and Release (ADSR). In this blog post, we will discuss each part in detail and explain how they affect the overall sound of a signal. So let’s get to the question, “what is a sound envelope?”

Sound Envelope
Learning about ADSR is the first step to sound design!

Signal Envelope/Sound Envelope

The sound envelope can be hard to understand at first but is really only four simple parts.


The attack of a signal is the initial rise in amplitude. It occurs at the beginning of the sound and lasts for a brief period of time. The attack is important because it sets the tone for the rest of the signal. A fast attack will create a sharp, punchy sound, while a slow attack will create a more mellow sound.

This sound has a quick attack


The decay of a signal is the decrease in amplitude between the attack and the sustain. It occurs after the attack and lasts for a certain amount of time. Decay starts as soon as the attack reaches its peak, and ends as soon as the sustain begins.

Sound with a short decay


The sustain of a signal is the part of the sound that remains at a constant level. It occurs after the attack and lasts for a certain amount of time. The sustain is important because it determines how long the signal will last before it begins to release.

A sustained note (zero decay or attack,)


The release of a signal is the final stage of the sound envelope. It occurs after the signal has reached its peak and decayed to zero. It is important because it determines how long it takes for a signal to fade away completely or if there will be any residual sound at all.

Sound with a long release, all audio clips from teachmeaudio.com

Examples of Sound Envelopes

You can hear different types of sound envelopes everywhere you look. For example, the attack, sustain, decay, and release of a trumpet are very different from the attack, sustain, decay, and release of a guitar. A guitar generally has a quicker attack, and a trumpet takes a much longer time to reach peak amplitude. A trumpet also has a much shorter sustain and decay than a guitar, which means it will fade out faster. It’s also important to note that there is no release on either signal because they both last indefinitely until the signal is turned off or fades away naturally (in this case).

The sound envelope of a signal is what makes one sound different from another. It’s important to understand how the signal envelope works so that you can create your own sounds in synthesizers, samplers, and other electronic instruments.

What is a sound envelope? ADSR Graph
ADSR graph

How to Hear Envelopes

The best way to hear envelopes is to listen to music that features lots of instruments playing at once. As you listen, pay attention to how each instrument comes in and out of the signal. For example, if there is a trumpet soloing over a bass line, listen carefully at when each note starts and stops. The signal envelope will tell you which notes are playing together so that you can hear the sound more clearly.

Signal envelopes can be heard everywhere you look, they are one of the most important aspects in making music. The signal envelope is what makes a signal sound different from another signal. It’s important to understand how the signal envelope works so that you can create your own sounds with synthesizers and samplers by changing their envelopes.

If you want to learn more about signal envelopes


Sound envelopes are an important concept in audio production and engineering. To become better at the sound design you should understand this core concept very well. I hope you enjoyed this post.

In this blog post we explained each part of the signal envelope and gave some examples. We also provided a few tips on how to best hear envelopes in music.

To learn more about signal envelopes, be sure to check out our other blog posts and tutorials!

Mark D.

Mark D.

Hi, I'm Mark. I've been playing instruments since I was just a little kid. I've played cello and piano for a few years, and recently picked up guitar. I've produced bad music. I also run this blog where I share interesting things I've learned. I hope you Enjoy my posts!

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