Pitch ABX Test — Tuning in Cents
Can you hear subtle 25-cent detuning at concert A440? Blind ABX intonation trials measured in cents sharpen musicianship. Free in your browser, no download.
Protect your hearing. Start at a low volume. Never raise the volume to make a tone audible. Levels are shown in dBFS, relative to full scale — not SPL.
How it works
Double-blind ABX musical pitch test synthesizing harmonic 440 Hz tones detuned in precise cents.
Musical Pitch & Fine Tuning
In musical performance, intonation accuracy is paramount. A note that is merely 10 cents flat or sharp will generate noticeable beating when played alongside another harmonic instrument.
The Cents Scale
Because human pitch perception is logarithmic, equal physical differences in Hertz sound wider in the low register and narrower in the high register. The cent normalizes this perceptual geometry across the entire audio spectrum:
$$\text{cents} = 1200 \times \log_2\left(\frac{f_{\text{detuned}}}{f_{\text{ref}}}\right)$$
- 25 Cents: Quarter of a semitone; immediately recognizable as out of tune.
- 15 Cents: Common amateur vocal variance; noticeable on sustained chords.
- 10 Cents: Typical studio tuning tolerance for rhythm section instruments.
- 5 Cents: Fine tuning discrimination for professional orchestral players.
- 2 Cents: Elite mastering and instrument intonation threshold.
Frequently asked questions
What is a cent in musical acoustics?
A cent is a logarithmic unit of measure for musical intervals. There are 100 cents in a semitone (half step) of twelve-tone equal temperament, and 1200 cents in an octave.
What is the average human pitch discrimination threshold?
Most non-musicians have a threshold of 10 to 25 cents. Professional violinists, vocalists, and piano tuners frequently detect intonation inaccuracies down to 2 to 5 cents.
How is cents calculated mathematically?
Cents difference n between frequency f1 and f2 is calculated as: n = 1200 * log2(f2 / f1).