Real Python: Build a Guitar Synthesizer: Play Musical Tablature in Python

Have you ever wanted to compose music without expensive gear or a professional studio? Maybe you’ve tried to play a musical instrument before but found the manual dexterity required too daunting or time-consuming. If so, you might be interested in harnessing the power of Python to create a guitar synthesizer. By following a few relatively simple steps, you’ll be able to turn your computer into a virtual guitar that can play any song.

In this tutorial, you’ll:

• Implement the Karplus-Strong plucked string synthesis algorithm
• Mimic different types of string instruments and their tunings
• Combine multiple vibrating strings into polyphonic chords
• Simulate realistic guitar picking and strumming finger techniques
• Use impulse responses of real instruments to replicate their unique timbre
• Read musical notes from scientific pitch notation and guitar tablature

At any point, you’re welcome to download the complete source code of the guitar synthesizer, as well as the sample tablature and other resources that you’ll use throughout this tutorial. They might prove useful in case you want to explore the code in more detail or get a head start. To download the bonus materials now, visit the following link:

Take the Quiz: Test your knowledge with our interactive “Build a Guitar Synthesizer” quiz. You’ll receive a score upon completion to help you track your learning progress:

---

Interactive Quiz

Build a Guitar Synthesizer

In this quiz, you'll test your understanding of what it takes to build a guitar synthesizer in Python. By working through this quiz, you'll revisit a few key concepts from music theory and sound synthesis.

Demo: Guitar Synthesizer in Python

In this step-by-step guide, you’ll build a plucked string instrument synthesizer based on the Karplus-Strong algorithm in Python. Along the way, you’ll create an ensemble of virtual instruments, including an acoustic, bass, and electric guitar, as well as a banjo and ukulele. Then, you’ll implement a custom guitar tab reader so that you can play your favorite songs.

By the end of this tutorial, you’ll be able to synthesize music from guitar tablature, or guitar tabs for short, which is a simplified form of musical notation that allows you to play music without having to learn how to read standard sheet music. Finally, you’ll store the result in an MP3 file for playback.

Below is a short demonstration of the synthesizer, re-creating the iconic soundtracks of classic video games like Doom and Diablo. Click the play button to listen to the sample output:

Once you find a guitar tab that you like, you can plug it into your Python guitar synthesizer and bring the music to life. For example, the Songsterr website is a fantastic resource with a wide range of songs you can choose from.

Project Overview

For your convenience, the project that you’re about to build, along with its third-party dependencies, will be managed by Poetry. The project will contain two Python packages with distinctly different areas of responsibility:

1. digitar: For the synthesis of the digital guitar sound
2. tablature: For reading and interpreting guitar tablature from a file

You’ll also design and implement a custom data format to store guitar tabs on disk or in memory. This will allow you to play music based on a fairly standard tablature notation, which you’ll find in various places on the Internet. Your project will also provide a Python script to tie everything together, which will let you interpret the tabs with a single command right from your terminal.

Now, you can dive into the details of what you’ll need to set up your development environment and start coding.

Prerequisites

Although you don’t need to be a musician to follow along with this tutorial, a basic understanding of musical concepts such as notes, semitones, octaves, and chords will help you grasp the information more quickly. It’d also be nice if you had a rough idea of how computers represent and process digital audio in terms of sampling rate, bit depth, and file formats like WAV.

But don’t worry if you’re new to these ideas! You’ll be guided through each step in small increments with clear explanations and examples. So, even if you’ve never done any music synthesis before, you’ll have a working digital guitar or digitar by the end of this tutorial.

The project that you’ll build was tested against Python 3.12 but should work fine in earlier Python versions, too, down to Python 3.10. In case you need a quick refresher, here’s a list of helpful resources covering the most important language features that you’ll take advantage of in your digital guitar journey:

• Assignment expressions
• Data classes
• Enumerations
• Protocols (static duck typing)
• Structural pattern matching
• Type hints

Other than that, you’ll use the following third-party Python packages in your project:

• NumPy to simplify and speed up the underlying sound synthesis
• Pedalboard to apply special effects akin to electric guitar amplifiers
• Pydantic and PyYAML to parse musical tablature representing finger movements on a guitar neck