DSP Audio Effects Project
Tremolo
Tremolo is an audio effect that uses amplitude modulation to create a wavering or trembling sound. The modulating signal, when multiplied with the original signal, varies the amplitude of the original signal, causing the trembling sound as the amplitude increases and decreases. Tremolo is most commonly used in electric guitar music and was originally created as a stand-alone unit, but it is now included in many amplifiers. The modulation can occur in the form of a sinusoid, but square and triangle waves (or a combination of the two) are most commonly used. It is common for an amplifier with this feature to include a dial allowing one to choose the waveform and amplitude of the modulation.
Our implementation of this effect shows both modulation by a square wave as well as a triangle wave. The other implementation features sinusoidal modulation. For both of these implementations, the amplitude of the modulation can be changed to vary the strength of the effect.
Our Implementation
Original: Concerning Hobbits (Live Clarinet) - LOTR Soundtrack
After Effect: Tremolo (triangle)
After Effect: Tremolo (square)
To demonstrate tremolo, we recorded a clarinet playing a piece from the Lord of the Rings soundtrack. It is titled clarinet_shire.mp3 in the project files page. Using the call_tremolo function, set implementation to 1, select either triangle or square wave, and set the gain to 0.8.
Tremolo (triangle)
Tremolo (square)
Other Implementation
Original
After Effect: Tremolo
This demonstration of tremolo also uses the shire_clarinet.mp3, and to apply the sinusoid effect use the call_tremolo function and set implementation to 2. This algorithm was found online, and the website is included in our references page.
Tremolo (sinusoid)
