Rhythm

Note values, time signatures, subdivisions, swing, syncopation, and tempo markings.

Note Values

Duration hierarchy
Whole note       ○     4 beats (in 4/4)
Half note        d     2 beats
Quarter note     ♩     1 beat
Eighth note      ♪     1/2 beat
Sixteenth note   ♬     1/4 beat
Thirty-second          1/8 beat

Dotted notes: add half the original value
  Dotted half:     d. = 3 beats
  Dotted quarter:  ♩. = 1.5 beats
  Dotted eighth:   ♪. = 3/4 beat

Triplets: three in the space of two
  Quarter triplet: 3 notes in 2 beats (each = 2/3 beat)
  Eighth triplet:  3 notes in 1 beat (each = 1/3 beat)
  Swing feel = long-short pattern (≈ 2/3 + 1/3)

Time Signatures

Common time signatures
Simple:
  4/4   Common time    4 quarter-note beats    (pop, rock, EDM)
  3/4   Waltz time     3 quarter-note beats    (waltz, some ballads)
  2/4   March time     2 quarter-note beats    (polka, march)
  2/2   Cut time       2 half-note beats       (fast, alla breve)

Compound (subdivide into 3):
  6/8   Compound duple   2 groups of 3 eighths  (jigs, some ballads)
  9/8   Compound triple  3 groups of 3 eighths
  12/8  Compound quad    4 groups of 3 eighths  (blues shuffle)

Odd meters:
  5/4   Five beats       3+2 or 2+3             ("Take Five")
  7/8   Seven eighths    2+2+3, 3+2+2, etc.     (prog rock)
  11/8  Eleven eighths   various groupings       (complex prog)

Top number: how many beats per measure
Bottom number: which note value gets one beat

BPM and Tempo

Tempo markings
Genre BPM ranges:
  Hip-hop:       80-100 BPM
  R&B:           90-110 BPM
  House:         120-130 BPM
  Techno:        125-150 BPM
  Drum & Bass:   160-180 BPM
  Dubstep:       140 BPM (half-time feel at 70)
  Trap:          130-170 BPM (half-time feel common)
  Pop:           100-130 BPM
  Rock:          110-140 BPM

BPM math:
  60 BPM = 1 beat per second
  120 BPM = 2 beats per second
  Beat duration = 60 / BPM seconds
  Bar duration (4/4) = 4 × 60 / BPM = 240 / BPM seconds

  At 120 BPM: bar = 2 seconds
  At 140 BPM: bar = 1.714 seconds
  16 bars at 128 BPM = 16 × 240/128 = 30 seconds
Delay/reverb timing
Quarter note delay = 60000 / BPM (milliseconds)
Eighth note delay = 30000 / BPM
Dotted eighth = 45000 / BPM
Sixteenth = 15000 / BPM

At 120 BPM:
  Quarter = 500 ms
  Eighth = 250 ms
  Sixteenth = 125 ms
  Dotted eighth = 375 ms

At 140 BPM:
  Quarter ≈ 428 ms
  Eighth ≈ 214 ms

Rhythmic Patterns

Fundamental patterns
4-on-the-floor (house, disco):
  KICK on every beat
  |K . . . |K . . . |K . . . |K . . . |
  1 & 2 & 3 & 4 &

Boom-bap (hip-hop):
  |K . . . |. . S . |. . K . |. . S . |
  Kick on 1 and 3&, snare on 2 and 4

Breakbeat:
  Syncopated, kick and snare displaced
  |K . . . |. . S . |. K . . |. . S K |

Reggaeton:
  |K . . K |. . S . |K . . K |. . S . |
  Dembow pattern: kick on 1 and "and of 2"

Shuffle/swing:
  Straight: |K . K . |K . K . |  (equal divisions)
  Swing:    |K . .K  |. .K . | (long-short pattern)
  Swing percentage: 50% = straight, 67% = triplet swing

See Also