Spotify – How to detect user music preference based on the songs played

Step 1: Extract Core Audio Features

For each song:

• BPM (tempo)

• Energy score (0–1)

• Loudness (normalized)

• Beat strength

Step 2: Compute Weighted Intensity Score

Intensity Score per song:

Intensity =
0.35 × BPM_norm

• 0.35 × Energy

• 0.20 × Loudness_norm

• 0.10 × Beat_strength

Step 3: Early Preference Index (EPI)

If first two songs are S1 and S2:

EPI = (Intensity_S1 + Intensity_S2) / 2

Classify:

• 0.0–0.33 → Low Energy

• 0.34–0.66 → Medium Energy

• 0.67–1.0 → High Energy

Step 4: Recommendation Trigger

Instead of waiting for 20+ interactions:

Immediately:

• Adjust homepage layout

• Adjust playlist ranking

• Modify autoplay direction