Become a member
Become a member

or
Continue with Google
Log in
Log in

or
Log in using a Google account
learning
Comment

More Basic Synth Effects

Sound synthesis, sound design and audio processing - Part 14
Share this article

In this article we'll take it from where we left off last week and continue exploring the main effects you can find on a synth.

View other articles in this series...

Flanger, phaser, chorus

Flanger and phaser effects stem from the delayed signal principle. According to this principle, the signal can be taken from the output to be resent to the input with a slight delay, or it can be split and mixed with a small time lag. In both cases, this delay creates a phase difference between both signals with the well-known consequences (see article 2): Some frequencies will be boosted while others will be attenuated or even completely canceled out. This is also known as a comb filter, because the spectral analysis of such a signal alternates between peaks (frequencies in phase) and dips (frequencies out of phase), like a comb.

Les effets dans la synthèse sonore

The sound of a flanger and a phaser is very similar. The differences between them have to do mainly with the way they work. A flanger produces frequency peaks and dips of constant dimensions and at fixed intervals. Whereas with a phaser, the depth and width of the dips and peaks can be modified.

A flanger example

00:0000:00

A phaser example:

00:0000:00

A chorus is based on the multiplying of voices with a slight difference between them, be it a time delay, a slight alteration of the fundamental frequency or the use of a vibrato out of sync.

A chorus example:

00:0000:00

Ring modulation

Les effets dans la synthèse sonore

Ring modulation is an evolved form of amplitude modulation. The former takes its name from the structure of the electronic assembly that produces it. A ring modulator is, in fact, a series of diodes forming…a ring.

Its operating principle is based on a carrier wave © whose amplitude is modulated by a modulating wave (M). The latter is often a sine wave, but not necessarily ─ don’t hesitate to try other waveforms if your ring modulator allows it, you will get very different results! The carrier wave can be any signal, simple or complex, depending on what the architecture of your synth allows. The effect produced by a ring modulator is very interesting.

To put it simply, let’s assume each of the waves, C and M, are sine waves. As long as the modulating wave doesn’t exceed 20 Hz – in other words, as long as it’s note audible to the humane ear – the ring modulator behaves a bit like an LFO (see article 6), and you get a tremolo effect. However, above 20 Hz, C and M are processed with the following result: The frequencies of the two original waves disappear and are replaced by two other frequencies. The first one is the result of summing the two original frequencies and the other one results from the difference between these same frequencies.

The sound produced by a ring modulator is often considered harsh, since, generally speaking, the two frequencies resulting from the sum/difference of the original ones don’t have any harmonic relation between them.

When using more complex waveforms, the ring modulator generates two frequencies for each sine wave of the carrier and modulating waves.

00:0000:00

Pulse width modulation – PWM

Another form of modulation often found on synths is the so-called “pulse width modulation” (PWM). Broadly speaking, in electronics, PWM is used to synthesize a continuous signal from an on/off signal. The latter is best represented by the asymmetrical square wave (a pulse wave) we saw in the fourth article of the series, which I invite you to reread if all this seems a bit too dense. 

Les effets dans la synthèse sonore

In this case, the on and off modes are represented by the high and low output states of the resulting waveform. The idea is that you can simulate any type of continuous signal by affecting the cyclic relationship of the square wave in question, without changing its frequency.

This principle is commonly used in domestic technology, for instance, to maintain a constant temperature by means of a thermostat without the need to continuously consume precious energy.

Fortunately, there are no such problems in sound synthesis. But then, what’s the use of PWM in music, you ask? Well, by simply varying the cyclic relationship, you are modifying the harmonic content of the waveform (but not the fundamental frequency or the overall amplitude). The modulation can be controlled by an LFO, giving it a cyclic motion.

In our example, however, we varied the pulse width manually.

00:0000:00

 

← Previous article in this series:
Synth Effects
Next article in this series:
Subtractive Synthesis: Straight to the point →

Would you like to comment this article?

Log in
Become a member
cookies
We are using cookies!

Yes, Audiofanzine is using cookies. Since the last thing that we want is disturbing your diet with too much fat or too much sugar, you'll be glad to learn that we made them ourselves with fresh, organic and fair ingredients, and with a perfect nutritional balance. What this means is that the data we store in them is used to enhance your use of our website as well as improve your user experience on our pages and show you personalised ads (learn more). To configure your cookie preferences, click here.

We did not wait for a law to make us respect our members and visitors' privacy. The cookies that we use are only meant to improve your experience on our website.

Our cookies
Cookies not subject to consent
These are cookies that guarantee the proper functioning of Audiofanzine and allow its optimization. The website cannot function properly without these cookies. Example: cookies that help you stay logged in from page to page or that help customizing your usage of the website (dark mode or filters).
Google Analytics
We are using Google Analytics in order to better understand the use that our visitors make of our website in an attempt to improve it.
Advertising
This information allows us to show you personalized advertisements thanks to which Audiofanzine is financed. By unchecking this box you will still have advertisements but they may be less interesting :) We are using Google Ad Manager to display part of our ads, or tools integrated to our own CMS for the rest. We are likely to display advertisements from our own platform, from Google Advertising Products or from Adform.

We did not wait for a law to make us respect our members and visitors' privacy. The cookies that we use are only meant to improve your experience on our website.

Our cookies
Cookies not subject to consent

These are cookies that guarantee the proper functioning of Audiofanzine. The website cannot function properly without these cookies. Examples: cookies that help you stay logged in from page to page or that help customizing your usage of the website (dark mode or filters).

Google Analytics

We are using Google Analytics in order to better understand the use that our visitors make of our website in an attempt to improve it. When this parameter is activated, no personal information is sent to Google and the IP addresses are anonymized.

Advertising

This information allows us to show you personalized advertisements thanks to which Audiofanzine is financed. By unchecking this box you will still have advertisements but they may be less interesting :) We are using Google Ad Manager to display part of our ads, or tools integrated to our own CMS for the rest. We are likely to display advertisements from our own platform, from Google Advertising Products or from Adform.


You can find more details on data protection in our privacy policy.
You can also find information about how Google uses personal data by following this link.