Stephan Bernsee's Blog

Mainz, August 27th, 2009 – Arnaud Gatouillat has posted an ActionScript3 port of our smbPitchShift code from the “Pitch Shifting Using the Fourier Transform” tutorial on his web site at http://iq12.com/blog/2009/08/25/real-time-pitch-shifting/. If you have Flash 10 installed on your computer you can run it directly off his web site in real time. Source code is also available.

With the increasing speed of todays desktop computer systems, a growing number of computationally intense tasks such as computing the Fourier transform of a sampled audio signal have become available to a broad base of users. Being a process traditionally implemented on dedicated DSP systems or rather powerful computers only available to a limited number of people, the Fourier transform can today be computed in real time on almost all average computer systems. Continue reading…

If you’re into signal processing, you will no doubt say that the headline is a very tall claim. I would second this. Of course you can’t learn all the bells and whistles of the Fourier transform in one day without practising and repeating and eventually delving into the maths. However, this online course will provide you with the basic knowledge of how the Fourier transform works, why it works and why it can be very simple to comprehend when we’re using a somewhat unconventional approach. Continue reading…

This tutorial gives a brief overview of the most popular algorithms used for achieving time stretching and pitch shifting in a musical context, along with their advantages and disadvantages. We provide audio examples to demonstrate common artifacts and effects associated with these processes, and provide pointers to papers and other resources on the net. Continue reading…