Wavetable Synthesis Algorithm Explained [Synth #001]

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Hi, my name is Jan Wilczek and I am an audio programmer and a researcher. Welcome to WolfSound!

WolfSound's mission is to provide high-quality, informative, and entertaining videos, articles, and courses on how to process sound by exploring mathematics, applying algorithms, and creating code in various programming languages.

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In this video, we are discussing what is wavetable synthesis, its advantages, disadvantages, and how it relates to other synthesis methods. It should serve as an introduction to the world of sound synthesis.

In case of any doubt in understanding, please, refer to the article above or ask a question in the comments 🙂

BIBLIOGRAPHY

These are the references I used for this article. If you are interested in the topic of sound synthesis, each of them is a valuable source of information.

[4] Marek Pluta, Sound Synthesis for Music Reproduction and Performance, monograph, AGH University of Science and Technology Press 2019.

Links above may be affiliate links. That means that I may earn a commission, if you decide to make a purchase. This does not incur any cost for you. Thank you.

TIME CODES

00:00 Introduction
00:41 Agenda
01:04 Sound synthesis definition
01:31 Sound generation pipeline
02:06 A need for a fast and memory-inexpensive synthesis method
02:59 Building a sine generator
04:58 How do computers calculate sine values?
06:12 What is a wave table?
06:36 Wave table index from phase
07:06 Phase wrapping
07:51 fmod function explanation
08:05 Final formula for wave table index
08:19 Interpolation methods for wavetable lookup
09:08 Graphical example of interpolation methods
11:16 Phase increment
12:23 Index increment
13:28 Phase increment vs index increment
13:53 Wavetable synthesis DSP diagram
15:49 An oscillator
16:37 What is VCO?
17:00 Sound examples of wavetable synthesis
17:20 Sine 440 Hz example
17:37 Sawtooth 440 Hz example
18:09 Aliasing in wavetable synthesis
18:51 Sawtooth 880 Hz example
19:37 Antialiasing oscillators
20:09 The main advantage of wavetable synthesis
20:23 Gaussians mixture 110 Hz example
20:54 How wavetable synthesis relates to other synthesis methods?
21:15 What is sampling?
22:28 Wavetable synthesis vs sampling
23:03 Single-cycle wavetable synthesis
23:16 Multi-cycle wavetable synthesis
24:29 Multiple wavetable synthesis
25:16 Summary
26:37 Complete tutorial on wavetable synthesis
26:54 Further reading

DISCLAIMER

The video contains a clip from "Skyfall" (2012) produced by Eon Productions, Metro-Goldwyn-Mayer Pictures, and Columbia Pictures and distributed by Sony Pictures Releasing.

All the copyrights belong to their respective owners. Copyright Disclaimer under Section 107 of the Copyright Act 1976, allowance is made for "fair use" for purposes such as criticism, comment, news reporting, teaching, scholarship, and research. Fair use is a use permitted by copyright statute that might otherwise be infringing. Non-profit, educational or personal use tips the balance in favor of fair use.

#sound #synthesis

[stulora]

Finally someone who explains it the way I understand! Thank you!

[andycordy]

I will never make time for the programming but thank you for helping me to understand the underlying principles.

[JeSuisNerd]

Massively underrated channel, dude. This has helped me so much in understanding wavetable synthesis enough to implement it in a lightsaber project. Insta-subscribed!

[BrianMendoza]

Great video! I followed the JUCE tutorial (from JUCE page) and I didn't quite get it until I watched your video. Thank you!

[HakanaiVR]

17:02 -ish yeah I have been wondering whether there might be a merit to modelling voltage in a software synth. It might make the code easier to understand for people familiar with analog synths? I was considering getting into making analog synth hardware, and making a simulator which worked more like the real thing would be like a stepping stone to making the real thing.

[cemolcay]

the old analog days :D
great video, subscribed!

[DawlessHouseMusic]

Love this series of videos. Thank you.

[flyingsquirrel]

Hey super awesome video, thanks a lot! I'm glad YT recommended your channel to me :)
One question: You said, the only way to overcome aliasing in wavetable synthesis would be to increase the sampling rate. Wouldn't it also help to use sinc interpolation instead of linear?

[tommymcpheemusic]

What math could one use to calculate the minimum wavetable size to make a completely lossless sine wave at a given bit depth?

[YippeePlopFork]

Great video! Thank you for taking the time to make this and share the information.

I come from an analogue synth background and I’m struggling to understand something:

If I implement the algorithm on a microcontroller, surely the frequency of the output will vary depending on the speed (clock) of the microcontroller? If the microcontroller reads through the wave table at 1 MHz, that will produce an output that is beyond the range of human hearing.

So, should I somehow set a timer or interrupt to read the wave table at a rate relating to the desired frequency or is there a way to read the wave table at a constant rate but still produce the desired output frequency?

Sorry if this is confusing…I’m struggling to wrap my head around the speed at which a microcontroller operates vs the read speed of the wave table vs the desired frequency vs the output frequency.

To me, it seems that the output frequency depends on the speed at which the wavetable is read; so reading through the wave table quicker would produce a higher pitched output…wouldn’t it? 🤦‍♂️

[petruccigp]

Hey Wolf! Keep it up, cool videos! BTW your mom is rad :)

[substance]

It can be confusing to newcomers as this isn't what modern software instruments call wavetable synthesis, where you have a table of complete waveforms.

[frankbaron]

did you know that 2 pi is the mathematical equivilent of a circle in radians?

[przekladanki]

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