Onset Detection in Audio Quiz

Answers and explanations appear as you take the quiz.

1. What exactly is an 'onset' in audio?
   • The moment an acoustic event begins, like a note's attack
   • The fade-out of a sound
   • The average loudness of a track
   • The end of a song
2. What does spectral flux measure for onset detection?
   • A rule that marks every beat as a note onset
   • Positive increases in spectral energy between successive frames
   • A decay detector that selects only falling energy
   • A pitch estimator that finds the nearest MIDI note
3. Why is half-wave rectification applied in spectral flux?
   • To amplify decays
   • To convert audio to text
   • So only rising (positive) energy changes contribute, ignoring decays
   • To slow down the audio
4. Which type of onset is hardest to detect?
   • A sharp drum hit
   • A loud cymbal crash
   • A snare backbeat
   • A soft, gradual violin swell
5. What does the peak-picking stage with an adaptive threshold prevent?
   • Double-triggering and false onsets
   • Audio compression
   • Pitch shifting
   • Stereo widening
6. What can a neural onset detector learn from labeled audio examples?
   • A guarantee that every onset will be detected
   • Patterns in the audio features that signal event beginnings
   • A fixed tempo that applies to every recording
   • The identity of every instrument without evaluation
7. What does onset backtracking do when detected times are used to create audio slices?
   • Moves each onset to the end of the entire recording
   • Replaces each onset with the nearest musical beat
   • Moves an onset to the nearest preceding local minimum of an energy signal
   • Adds a fixed one-second delay after every peak
8. What can happen when an onset model is transferred to a different instrument or dataset?
   • Its predictions are guaranteed to remain identical
   • The audio automatically becomes monophonic
   • The model no longer needs a time-frequency input
   • Its performance may change and should be evaluated in the new domain