Background

Music has been an integral part of our lives right from the advent of time. The simple combinations of a few notes have the power to enchant and calm our souls. Music has proved to relax and heal, cause upliftment, boost concentration and so on. Among the most common instruments used to create music, the piano occupies a special place in the Hall Of Fame.

However, pianos are limited in terms of the sound they produce. In 1876, this paved the way for electronic synthesizers to make their mark in music history. Synthesizers are musical instruments that can generate any desired sounds by the controlled manipulation of audio waveforms. Standard techniques for synthesizing sounds include additive, subtractive, frequency modulation, wavetable and granular synthesis. Irrespective of their underlying approach, most synthesizers today are a derivative of the piano; the identical keyboard in both of these instruments enables musicians to transition seamlessly. Nowadays, almost all the music we hear on TV, mobiles, and concerts is produced using synthesizers. They have revolutionized the music industry and put many traditional instruments at the risk of becoming obsolete. Popular synthesizer manufacturers include Yamaha, Korg, Roland and Casio.

With the advent of computers, synthesizers are now implemented as computer software using digital signal processing (DSP) and are known as software synthesizers or softsynths. Softsynths are usually cheaper and more portable than dedicated hardware. Many popular hardware synthesizers are no longer manufactured but have been emulated in software. In some cases, these emulations have graphical interfaces that model the exact placements of the original hardware controls. Some simulators can even import the original sound patches with an accuracy nearly indistinguishable from the original synthesizer. Legendary synthesizers such as the Minimoog, Yamaha DX7, Korg M1, Prophet-5, Oberheim OB-X2, Roland Jupiter 8 and ARP 2600 have been recreated in software.

The music industry underwent another great revolution in 1996 when Steinberg, a musical software and equipment company from Hamburg, Germany, released the SDK for Virtual Studio Technologies (VSTs) alongside its Digital Audio Workstation (DAW) Cubase 3.02. Using the VST specification, softsynths could be integrated into DAWs in the form of add-on plugins, making millions of instruments and effects accessible from music-making software like FL Studio and Ableton. Today, VSTs are indispensable in music production, and popular plugins like Serum and Massive are essential tools in almost every music project.

The Project

In this project, we have implement OVERPOWER, a subtractive software synthesizer in National Instruments LabVIEW, which uses two sound generators (called oscillators) and has facilities for creating sound effects like filtering, distortion and phase shifts. This project uses some of the NI packaged VIs. These are:

• Function Generator VI; for creating the basic waveforms.
• Butterworth Filter VI; for sound filtering.
• Sound handling VIs; for configuring audio output devices and producing sound.

Main Components

Sound oscillators

The sound oscillators incorporate function generators to produce oscillating sound waves in the form of the square wave, triangle wave, sawtooth wave and sine wave. When the optional second oscillator is enabled, its output is superimposed with that of the first oscillator to produce a complex waveform. The phase difference between these oscillators can be adjusted to further adjust the waveform.

Sound Input

The user can input notes using a keyboard, just like playing the piano. The ASD row acts as the keyboard for OVERPOWER. Specifically, the “A” key corresponds to the C4 note, “S” key corresponds to D4, and so on. There is also an autoplay mode which has two sub-modes:

• Constant Sound; a constant 440 Hz note is played out. This mode can be used to test out user-created waveforms.
• Auto Music; a chaotic tune is automatically produced by a baked-in algorithm within the VI.

Sound effects

OVERPOWER has built-in sound effects. The most interesting one is the distortion effect (similar to those used by electric guitar players). The extent of distortion produced is controllable to obtain a suitable sound output. Other effects include variable-order lowpass, highpass, bandpass and band-reject filters made using Butterworth filter VI; volume adjusts, cutoff adjust and transpose sound option.

Use

This VI mimics a simple yet effective synthesizer that is capable of producing the desired sound wave. The user can create any desired tone by adjusting the provided controls on the GUI; the onboard graphical display will help them visualize the generated waveform. For playing music using the synthesizer, the user can either use the ASD row of the computer keyboard or set the instrument to the auto music mode.

See it working:

Additional Resources

1. Git Repository; Licensed under the GNU General Public License v3.0