Constant-Q Transform for Audio Quiz

Answers and explanations appear as you take the quiz.

1. How are frequency bins spaced in a Constant-Q Transform?
   • Logarithmically, matched to musical pitch
   • Linearly, evenly in hertz
   • Randomly
   • Only at multiples of 1000 Hz
2. What does the 'Q' in Constant-Q refer to?
   • The number of channels
   • The quality factor: the ratio of center frequency to bandwidth, kept constant
   • A queue of audio buffers
   • Quantization level
3. Why does the CQT use longer analysis windows at low frequencies?
   • To save memory
   • Because low frequencies are louder
   • To achieve finer frequency resolution where notes are closely spaced in hertz
   • To add reverb
4. What happens to a CQT pitch pattern when a chord is transposed up one octave?
   • It becomes a single DC component
   • Its bins shift by a different amount at each note
   • It becomes identical in absolute bin locations without shifting
   • It shifts upward by one octave’s fixed number of frequency bins
5. How many CQT bins per octave are commonly used to align with semitones?
   • 12
   • 3
   • 100
   • 1000
6. How does the documented librosa CQT implementation compute the transform?
   • By computing each filter from scratch with no shared processing
   • With a recursive subsampling method
   • By recording the audio twice
   • By ignoring all low frequencies
7. What does a chroma-CQT representation do with bins from different octaves?
   • It discards all pitch information
   • It converts audio into RGB images
   • It folds them into pitch classes
   • It assigns each bin a speaker identity
8. What does one column of a time-frequency CQT matrix typically represent?
   • A complete MIDI score
   • A 3D camera pose
   • A single global loudness score for the whole recording
   • CQT coefficients across frequency bins for one analysis frame in time