Getting into synthesis can be a very overwhelming experience. You may be in the common situation of having just received your first synth and still being rather unfamiliar with what all the knobs do. For some, this is actually quite an exciting concept, as it lets you jump into a world unknown. Yet, there will likely come a time when you will want to start developing some control over what it is you are making. While turning knobs in a random manner can produce gratifying results, often you will wish you knew what made those results so attractive. Luckily, for those that are in this or a parallel position, there is something you can do about it.
Synthesizers are not one and the same, however, they do often build off alike foundation. There is a set of core elements that most synthesis revolves around in one way or another. More than likely, when dealing with your first synth, knowing how these basic elements work will be the most important step of your learning. Even when dealing with more complex forms of synthesis, it all comes back to the core things laid out below.
As you are going through these ideas, make sure you attempt to relate them to your specific instrument. It may be hard to do this if you are an absolute beginner, but keep in mind these things can take time. The more you use your synth, the more these ideas will make sense to you.
Oscillators are the perfect place to start understanding synthesis. They are the building blocks of all the sounds you will be making. So what are they exactly? Essentially, a synth’s oscillator(s) is the sound source you are able to craft with. This source fluctuates in a particular shape that can have varying characteristics sonically speaking. The result of this oscillation is what we refer to as a waveform.
There are generally considered to be 4 standard waveforms that oscillators will take the shape of. Included in these forms are Sine, Triangle, Sawtooth, and Square. Sometimes, synths will have their own unique takes on these, but the four mentioned are the main ones you will use. Regardless of what wave shape you have, it functions as a cornerstone for you to build off.
Envelopes and ADSR
A very logical step after addressing the oscillator is understanding envelope generators (EG). EGs have everything to do with manipulating the amplitude of your signal. And amplitude is simply volume but in the context of a waveform. So yes, the amplitude is just how high the peak of the wave is. Now, where the EG comes in is when we alter the signal volume (or peak height) over time. This type of manipulation is how you can shape the response of the sound you are working with. To understand how this works the standard of ADSR has been created.
- Attack –
- The first part of the envelope is the attack. A very slow attack will rise or swell for a while before hitting the peak, while a rather fast attack will reach the peak quickly enough to where you might not hear much of it. You can also get anything in between these two extremes. This is the part of the envelope that exists until the initial peak is meant.
- Decay –
- This is the transition from the initial peak to where the note sustains. Controlling this time is like controlling the initial fade, but once there is no longer a dip in volume, we exit this part of the envelope.
- Sustain –
- Once the decay is settled into a constant volume, we have arrived at the sustain. This will control how long the sound is held while the signal is being sent. Sustain ends when the signal is no longer being sent (i.e. once you have released the key).
- Release –
- Release is the time that it takes the sound to reach nothing after the key is no longer being pressed. Basically, you are controlling how long it takes for things to end.
You can master these four parts to an envelope to get the exact reactiveness you are looking to craft. For example, if you want to create a violin feeling to your sound you would want a relatively long Attack, little to no Decay, very long Sustain and a pretty quick release. You can use this for basically any real-world instrument or to copy a synth sound you have heard before. Even for making the more unorthodox sounds, understating how ADSR works is key to having total creative control.
Filters are vital in bringing the character into your synthesizer. Essentially, filters aid in the fundamental timbre of your sound. Most of the time your filter will be cutting either the low (high pass) or high (low pass) frequencies of the waveform. To clarify, the two main filter types are high pass and low pass, each named for which frequencies they are ignoring. Really, these are just specific types of EQ used frequently in synthesis. There are a few other common filter types, but that is getting a little ahead of ourselves for this article.
In filtering, the most important control points are cut-off and resonance. The cut-off point is the point at which everything above is cut. And the resonance point is a boosted frequency that takes place right at the cut-off point. These two parameters working together is what can offer a wide variety of character and timbres.
Now it’s time to talk about something you can’t hear. Measured in Hertz, the human range of hearing is 20 to 20,000. Low-Frequency Oscillators (LFOs) are built from frequencies below 20hz. So, how do we use them then? Well, while you can’t hear these frequencies, they still exist and function just like other frequencies. Your LFO can be any of the waveshapes mentioned above, and they can alter different aspects of the wave.
There are A LOT of ways you can utilize the LFOs in your synth. Depending on what you are affecting, you can use them to create things like tremolo (amplitude) and vibrato (pitch). Many iconic synth sounds have come about in large part thanks to the crazier side of LFOs. You can do so much with these lower frequencies, LFOs are some of the most interesting areas in synthesis.
Very few synth sounds will ever be at their best completely dry. Common effect types that are used in synthesis include distortions, delays, reverbs and modulations. Just like with all of this stuff, you can get as deep as you would like. For each of the effect types listed there are literally thousands of iterations and infinite ways to use them. Some popular examples might be things like a ping-pong delay or a stereo plate reverb, but those are just scraping the tip of the iceberg.
You won’t always get built-in effects with every synth you buy. Often, they might include a distortion and possibly a couple of delays and reverbs. Effects are frequently sold as individual units that you can add to your synth rig. However, don’t spend too much time on these if you are an absolute beginner, learn how to do basic synthesis first. I just wanted to be sure to include effects here because of how important they are to most synth sounds.
And with that, you should have a basic introduction to synthesis. Keep in mind that the ideas here are revolving around subtractive synthesis. While these concepts still apply to types like FM and Additive synthesis, there are definitely some needed asterisks with them. But 99% percent of the time you will be starting on a negative synth.
Hopefully, now you are feeling a little bit more confident around your synth. I know it is probably still a little overwhelming for the absolute beginners out there but just take your time. You can (and should) always revisit and develop a deeper understanding of these concepts as you go. Collecting knowledge of how to create sounds is definitely a lifelong process!