After working through the material of this lecture, you should be able to answer the following questions:

- What is the relation between musical pitches and frequency?
- How can one assign a frequency range to a given musical pitch? How are a cutoff frequency and a bandwith defined?
- What is a log-frequency spectrogram? How can it be computed? (See Eq. 3.3 and Eq. 3.4.)
- What is the motivation for introducing chroma features? Which musical aspects are captured by these features?
- How can one compute chromagrams? (See Eq. 3.6.)
- What is the goal of logarithmic compression? How is it computed? (See Eq. 3.7.)
- What is the goal of feature normalization? How can it be computed? (See Eq. 3.9 and Eq. 3.10.)
- What are the effects of tuning deviations on the quality of chroma features? How may one handle such deviations?
- How can one adapt chroma features to simulate musical transpositions?

MÃ¼ller, FMP, Springer 2015

Chapter 3: Music Synchronization

- Section 3.1: Audio Features
- Section 3.1.1: Log-Frequency Spectrograms
- Section 3.1.2: Chroma Features

- Exercises
- Exercise 3.3
- Exercise 3.6

- Audio Features: Slides (PDF), Handouts (6 slides per page) (PDF)
- Log-Frequency Spectrogram: Handwritten Notes (PDF)

Music Processing using Chroma Features (17:37)

Music representations; music synchronization; interpretation switcher; audio features; chroma; alignment; dynamic time warping; score followingPitch, Pitch Class, Octave Designation, Enharmonic Equivalence (7:55)

Easy explanation of the concept of pitch classes