Least-Squares Local Tuning Frequency Estimation for Choir Music
Presented at the 131st AES Convention, 2011 October 20-23, New York, USA Convention homepageAbstract
Choir conductors often have to deal with the problem that the tuning pitch of a choir tends to decrease gradually over time. For that reason, we present an algorithm which measures and displays the tuning frequency evolution for polyphonic choir music over time. Basically, it analyzes the short-time Fourier spectrogram, picks out the most important peaks, and determines their frequencies. From these frequencies, the algorithm determines the concert A pitch that leads to the smallest least-squares-error when the measured frequencies are sorted into a semitone grid. The algorithm has been implemented on the Android platform and works in real-time.Paper
For copyright reasons, the paper is currently not published here. Please use the AES website for purchase and download.Poster
PDF (2 MB)Sound Examples for Figure 5
Gospel choir singing "An Irish Blessing". All sound examples are stored in the FLAC format (Free Lossless Audio Coding). Details and decoding software can be found here.
- Original file with pitch decreasing about one semitone: FLAC (6 MB)
- Pitch corrected file: FLAC (6 MB)