Boom bap

History and character

Origins

Boom bap is the sound of New York's East Coast between the late '80s and the mid-'90s; the name is the onomatopoeia of the kick ("boom") and the snare ("bap"), also popularized by the title of KRS-One's album "Return of the Boom Bap" (1993). It was born from samplers with limited memory: the E-mu SP-1200 (12-bit, 26.04 kHz, about 10 seconds of sampling), the Akai S950 and the MPC60 (with Roger Linn's swing). In the mid-'80s Marley Marl discovered that he could sample single drum hits from a record and replay them: the beginning of the beat built "in pieces."

Producers and artists

DJ Premier (Gang Starr), Pete Rock (with C.L. Smooth), Large Professor, RZA (Wu-Tang Clan), Buckwild and the D.I.T.C., Havoc (Mobb Deep), Q-Tip, Showbiz, Diamond D and Lord Finesse defined the aesthetic; the key albums are "Enter the Wu-Tang (36 Chambers)" (1993), Nas's "Illmatic" (1994, with Premier, Pete Rock, Large Professor and Q-Tip), The Notorious B.I.G.'s "Ready to Die" (1994), Mobb Deep's "The Infamous" (1995), Gang Starr's "Moment of Truth" (1998).

Aesthetics and evolution

Rough and dusty: heavy, swung drums taken from vinyl, filtered and chopped jazz and soul samples, scratches on the hooks, technical and narrative rap in the foreground. After 2000 the sound moved to the underground (Rawkus, Jedi Mind Tricks, Little Brother with 9th Wonder) and returned to prominence in the 2010s with Joey Bada$$ and Pro Era, and above all with Buffalo's Griselda (Westside Gunn, Conway the Machine, Benny the Butcher, producers Daringer and The Alchemist), which revives "mafioso rap" over drumless or nearly drumless loops. In Europe it has a very strong scene (Italy, France, Germany, Poland).

Scales and keys

In boom bap the scale is almost always that of the sample: the producer doesn't choose a scale, he chooses a record. Understanding the mode of the sample is needed to add bass, countermelodies or hooks without clashes.

Dorian (the most typical)

• Formula: 1 2 b3 4 5 6 b7 — semitones 2-1-2-2-2-1-2.
• Example in C: C D Eb F G A Bb.
• Characteristic note: the major 6 (A), which sweetens the minor and gives the modal jazz color (the "So What" sound).
• Chords: Cm7 (i) – Dm7 (ii) – Ebmaj7 (III) – F7 (IV) – Gm7 (v) – Am7b5 (vi°) – Bbmaj7 (VII).
• Use: Rhodes and jazz piano loops, i–IV vamp (Cm9–F13), upright bass lines that pass through the 6.
• Real example: many Blue Note and CTI samples of the '60s–'70s used by Pete Rock and Q-Tip run in Dorian.
• Mistakes: playing an Aeolian bass (Ab) over a Dorian sample (A).

Natural minor (Aeolian)

• Formula: 1 2 b3 4 5 b6 b7 — 2-1-2-2-1-2-2.
• Example in A: A B C D E F G.
• Characteristic note: b6 (F), melancholic.
• Chords: Am7 (i) – Bm7b5 (ii°) – Cmaj7 (III) – Dm7 (iv) – Em7 (v) – Fmaj7 (VI) – G7 (VII).
• Use: the "dark" boom bap of Mobb Deep and RZA: minor pianos, tense strings, i–VI loops.
• Real example: "Shook Ones, Pt. II" (Mobb Deep, 1995) builds tension on treated minor samples (including a fragment of Herbie Hancock's "Jessica") that always sound off-axis.

Blues scale and minor pentatonic

• Blues in A: A C D Eb E G (1 b3 4 b5 5 b7) — 3-2-1-1-3-2.
• Minor pentatonic in A: A C D E G — 3-2-2-3-2.
• Use: sampled bass and guitar riffs, soul horns, scratches.
• Characteristic note: the passing b5 (Eb).

Chromaticisms from the sample

Cutting a sample mid-phrase "freezes" passing chords, chromatic notes and dissonances (b9, #11, clusters). They are not mistakes: they are part of the sound. If you add a bass, follow the lowest note of the sample and not the "theoretical" chord.

How to choose / recognize

1. Find the tonic (the note the loop "rests" on).
2. Listen to the sixth: major → Dorian; minor → Aeolian.
3. Listen to the third: major → Mixolydian or major (bright soul samples).
4. If the sample is pitched (e.g. +2 semitones at 33→45 rpm), recalculate the key.

Harmony

Static and sampled harmony

Loops of 1–2 bars with 1 or 2 chords, often extended (m7, m9, maj7, 11). No concluding cadence: the tonal center is an implicit pedal on the tonic of the sample.

Harmonic layering

Many producers (RZA, Premier) overlap two samples from different records: the result is clusters and light polytonality (a piano in Dm over strings in Eb) that create unease. Rule: the two samples must share at least the root or the fifth, or be clearly separated in register.

Chop and rearrangement

The sample cut into 4–16 pieces (chop) and replayed on pads creates new progressions: a record in Fmaj7–Em7 becomes Em7–Fmaj7–Em7–Am7. This is the true "composing" of boom bap.

Harmonic rhythm

One chord per bar or every two bars; in the hook sometimes the sample changes (a second, more open loop).

Voicing (if you play it yourself)

Close four-note chords in the C3–C5 register: Dm9 = F A C E with D in the bass; Cmaj9 = E G B D; shell voicings for Rhodes (1-b7-b3, e.g. D-C-F). Filter and saturate as if it came from a vinyl record.

Typical progressions

Rhythm and groove

Feel

Swing on the sixteenth notes between 54 and 62% (MPC presets 54, 58, 62; the SP-1200 had its own swing, much appreciated). Kick and snare more quantized, hi-hats more "drunk." Relaxed feel, behind the beat: the snare often arrives 10–25 ms late relative to the grid.

Loop structure

Loop of 1–2 bars with small kick variations every 4 bars. Fills almost absent, replaced by stops (everything stops on a punchline) and drops (the sample drops out and the drums remain).

Accents

2 and 4 strongly marked; the syncopated kick falls on the last sixteenth notes of the beats (steps 8, 11, 16) and creates the "bounce" of the head nod.

Drums

Role

The drums are the center: they must "move the head" (head nod). Big, dirty, compressed sound, taken from vinyl.

Kick

• Basic pattern (16 steps): x......x..x..... = 1, "a" of 2, "e" of 3.
• Variations: addition on step 3 ("e" of 1) in bar 2; double hit 11–12; kick on the 4-e (step 15) before the turnaround.
• Velocity: 120 on the 1, 100–110 on the syncopations.
• Often layered with a short sub (50–60 Hz sine, 150–250 ms) or a low 808 kick under the break.

Snare

• On 2 and 4 (steps 5 and 13), full, with body and "crack": layered with a clap or a second, brighter snare.
• Ghost notes at velocity 30–50 on steps 4, 8 or 16.
• Slightly late (10–20 ms) for the "lazy" feel.

Hi-hat

• Swung eighth notes (steps 1, 3, 5, …), alternating velocity 100/65; open on the "e" of 4 (step 15).
• Alternatively, uncut hats from the original break, or shaker in place of the hats.

Sampled breaks

"Impeach the President" (The Honey Drippers), "Funky Drummer" (James Brown), "Synthetic Substitution" (Melvin Bliss), "Amen, Brother" (The Winstons) and many others: cut into single hits (chops) and reprogrammed, or used as a loop under the programmed drums.

Interaction with bass and voice

The bass follows the kick (same positions or anticipated by a sixteenth note). In the verse the drums stay identical: it is the voice that varies. The hook scratches fill the gaps between the snares.

Sections

• Intro: sample alone or with filtered drums.
• Verse: basic pattern.
• Hook: a clap, an open hat or a tambourine is added; scratches.
• Stop: everything stops for 1–2 beats on the punchlines.

Sounds

Kick: body 60–100 Hz, soft attack (from vinyl). Snare: body 180–250 Hz, crack 2–5 kHz, short tail. Grain: 12-bit / 26 kHz (SP-1200), tape saturation.

Typical mistakes

Rigid quantization, hats too bright and digital, "modern" snare that is too clean, kick with too much sub (boom bap has its weight at 60–100 Hz, not at 40).

Bass

• Source: bass sampled from the original record and low-pass filtered (150–250 Hz), or upright/electric bass played or sampled note by note; for some producers (DJ Premier) a long 808-type sub tuned to the tonic.
• Rhythm: follows the kick, often with the same syncopations; leaves the snare space free.
• Notes: root and fifth; in jazz loops, passages through the 6 (Dorian) or chromatic approach notes (B–C over C minor).
• Register: 50–120 Hz fundamental, less sub than trap; it must sound "round" and warm.
• Relationship with the kick: if the bass is sampled together with the loop, the kick must be tuned by ear to the bass (±1 semitone) and lightly sidechain compressed (1–2 dB).
• Examples: the upright bass lines of Q-Tip and Pete Rock beats; Premier's subs in "Mass Appeal" (Gang Starr, 1994).

Harmonic instruments

• Samples of jazz piano, Rhodes, vibraphone, soul strings, horns (trumpet and sax stabs), jazz guitars, in the middle register; often pitched down to darken them and filtered (HP 150 Hz, LP 6–8 kHz).
• Organ (Hammond) in some gospel and soul loops.
• Voicings are those of the record; if you play it yourself, close four-note chords, no notes below C3 besides the bass.
• Layers: at most two simultaneous samples, separated in register (one low and one high).

Melody and vocals

• Rap: rhythmic and technical, flow on sixteenth notes with multisyllabic and internal rhymes, medium-low spoken register. Storytelling is central.
• Hook: scratches of phrases from other records (DJ Premier is the master: phrases from 3–4 different rappers assembled into a new phrase), a chanted refrain by several voices, or a short soul sung hook.
• Backing vocals: rare; gang vocals and supporting voices (hype man) on the last words.
• Effects: compression, light saturation, little reverb; no Auto-Tune.

Instruments

Sampler (E-mu SP-1200, Akai MPC60/3000, S950, Ensoniq ASR-10), turntables and mixer for scratching, breakbeats from vinyl, piano, Rhodes, upright bass, vibraphone, horns, sampled strings, rap voice, DJ voice (cuts).

Drum patterns

Synths and sounds

• Stage-73 V — Sampled Rhodes: Slow tremolo (2–3 Hz), moderate amp drive; then low-pass at ~6 kHz, 12-bit bitcrusher and saturation to make it sound "off a record." Play 1–2 bars and sample the result.
• Piano V — Jazz piano for chops: Upright with distant mics, high mechanical noise: play four-note chords, then cut and rearrange as if it were a vinyl record.
• Mellotron V — Pseudo-sampled flutes and strings: Tapes already have wow and flutter: flutes and strings sound vintage right away, ideal for melancholic RZA-style loops.
• Emulator II V — Grain of the historic sampler: 8-bit conversion and analog filters replicate the grit of the SP-1200/S950 on any sound.
• Mini V — Sub under the sample: Sine or triangle with a closed filter, no glide, decay 300–600 ms: reinforces the tonic under a sampled bass that is too light.
• B-3 V — Soul organ: Drawbars 888000000 with slow Leslie for gospel organ pads in the warmest loops.

Song structure

Three 16-bar verses are the norm. The beat is a loop of 1–2 bars: the arrangement is done with mutes (removing drums or sample) and with a second sample in the hook. Length 3:30–4:30.

Mixing and mastering

Sonic goal

Big, dynamic drums, warm "background" sample, dry voice in front. The sound is narrow (almost mono), saturated, with soft highs. References: "Illmatic" (Nas), "Moment of Truth" (Gang Starr), "The Infamous" (Mobb Deep), today "Pray for Paris" (Westside Gunn) and "Alfredo" (Freddie Gibbs & The Alchemist). Balance: voice 0, snare −3, kick −3/−4, bass −5, sample −9/−12.

Kick

• EQ: HP 30 Hz; body 60–90 Hz (+2/+3 dB, Q 1); cut 300–400 Hz (−3 dB, Q 2); click 2–4 kHz (+1/+2 dB).
• Compression: FET (1176 ratio 4:1, slow attack, fast release) 3–5 dB GR.
• Saturation: tape (Kramer Tape, light Fruity Blood Overdrive), 12-bit bitcrusher for SP-1200 grain.
• Space: none; mono, center.

Snare

• EQ: HP 100 Hz; body 200 Hz (+2/+3 dB); cut 500 Hz (−2 dB); crack 3–5 kHz (+2/+3 dB).
• Compression: 4:1, attack 10 ms, release 100 ms, 4–6 dB GR; parallel on a bus (ratio 10:1, attack 1 ms, 10–15 dB GR, mixed in at −8/−12 dB) for body and sustain.
• Saturation: Decapitator mode "E" or "N", drive 3–4, mix 30–50%.
• Space: short room (0.4–0.7 s) or 1 s plate at −18/−22 dB, return HP 300 Hz / LP 7 kHz.

Hi-hat and percussion

• EQ: HP 400 Hz; LP 12–14 kHz to remove their "digital" quality; cut 6–8 kHz if they sting.
• Pan: hats slightly right (+15), shaker left (−25).
• Automation: −2 dB during the denser verses.

Bass

• EQ: HP 35 Hz; fundamental 60–100 Hz; LP 3–5 kHz if sampled (removes hiss); cut 250 Hz if it muddies.
• Compression: opto (LA-2A) 3–4 dB, or VCA 4:1 attack 30 ms.
• Saturation: light tube for harmonics at 150–300 Hz.
• Mono below 150 Hz.

Sample / loop

• EQ: HP 120–200 Hz (remove the record's bass if you use a new bass); LP 6–9 kHz; cut 2–4 kHz (−2/−4 dB) for the voice, better with dynamic EQ sidechained from the vocal.
• Compression: light (2:1, 1–2 dB) or none.
• Saturation: tape, vinyl (iZotope Vinyl, RC-20: wow 10–20%, noise −40 dB).
• Space: almost none: the sample already has the record's ambience.
• Stereo: narrow to 50–70% ('70s vinyl is often nearly mono).

Lead vocal

• EQ: HP 80–100 Hz; −2/−3 dB at 250 Hz; +2 dB at 3–4 kHz; +1.5 dB shelf at 10 kHz.
• Compression: 1176 (4:1, 4–6 dB GR) + LA-2A (3 dB GR).
• De-esser: 6–7 kHz, 3–5 dB.
• Saturation: light, console or tape style.
• Space: almost dry; slap delay 80–120 ms at −20 dB or 1/4 delay on the tails; short plate (0.8 s) at −24 dB.

Doubles and hype

Doubles only on the last words of the bars, −6/−8 dB, pan ±50; wide hook gang vocals (±70) with some room.

Scratch

• EQ: HP 200 Hz, presence at 2–3 kHz; compression 4:1 to level the cuts; center pan or slightly off-axis.

Buses and groups

• Drum bus: SSL G-bus 4:1, attack 30 ms, auto release, 2–4 dB GR; tape saturation; possibly a 12-bit bitcrusher in parallel (mix 20–30%).
• Music bus: tape + soft EQ.

Sidechain

Kick → bass (1–3 dB); voice → sample (dynamic EQ 1–4 kHz, 2–3 dB).

Master

Soft EQ → tape → bus compressor (2:1, 1–2 dB) → limiter. Target −10/−8 LUFS integrated, short-term in the hooks −8, true peak −1 dBTP. PLR 9–11 dB: boom bap lives on transients, don't squash it.

Common mistakes

Sample too loud covering the voice; highs too bright (the genre is "dark"); kick with too much sub and little punch; stereo that is too wide; reverb on the voice.

Reference tracks for the mix

• Nas — N.Y. State of Mind (1994)
• Gang Starr — Mass Appeal (1994)
• Mobb Deep — Shook Ones, Pt. II (1995)
• Wu-Tang Clan — C.R.E.A.M. (1993)
• Joey Bada$$ — Waves (2012)
• Westside Gunn & Conway — Shower Shoe Gunn (2017)

Reference listening

• Gang Starr — Mass Appeal (1994)
• Nas — The World Is Yours (1994)
• Pete Rock & C.L. Smooth — They Reminisce Over You (T.R.O.Y.) (1992)
• Mobb Deep — Shook Ones, Pt. II (1995)
• Wu-Tang Clan — C.R.E.A.M. (1993)
• The Notorious B.I.G. — Unbelievable (1994)
• Joey Bada$$ — Waves (2012)
• Benny the Butcher — 18 Wheeler (2018)