Celtic music

History and character

“Celtic music” refers to the musical traditions of the Celtic nations: Ireland, Scotland (Highlands and islands), Wales, Cornwall, the Isle of Man, Brittany, and by extension Asturias and Galicia in Spain, as well as the diasporas (Cape Breton in Canada, Appalachia in the United States). The term as a musical label spread in the 1960s–70s with the revival (the Breton Alan Stivell used it from the early 1960s and relaunched the Celtic harp). The most influential tradition is the Irish one: instrumental dance music (reel, jig, slip jig, hornpipe, polka, slide, mazurka, waltz), slow airs, sean-nós singing (“in the old style”: unaccompanied solo singing, highly ornamented), ballads in English and in Gaelic, harp music (Turlough O'Carolan, 1670–1738).

The typical setting is the session (seisiún) in pubs, where musicians play “sets” of tunes from the same family; the first known modern session was held in London in 1947. The revival of the 1960s–70s created the groups that defined the modern sound: The Chieftains (1963, with Paddy Moloney), Planxty (Christy Moore, Dónal Lunny, Andy Irvine, Liam O'Flynn), The Bothy Band (1974), Clannad, De Dannan, The Dubliners; then Altan, Dervish, Lúnasa, Solas, Kíla, the fiddler Martin Hayes. In Scotland the Highland bagpipe, the fiddle (strathspeys and reels of Cape Breton), groups such as Capercaillie, Runrig, Battlefield Band, Lau; in Brittany the fest-noz dance with biniou and bombarde; in Galicia the gaita (Carlos Núñez).

Celtic has also become a pop and cinematic aesthetic: Clannad (Harry's Game, 1982), Enya (Watermark, 1988, with Orinoco Flow; her multitrack vocal layers produced with Nicky and Roma Ryan), Loreena McKennitt, Riverdance (Bill Whelan, born as the interval act of the 1994 Eurovision), the Celtic punk of the Pogues and the Dropkick Murphys, the soundtracks of James Horner (Braveheart 1995, Titanic 1997 with uilleann pipes and tin whistle), Howard Shore (the Shire in The Lord of the Rings).

Scales and keys

Celtic music is modal: pieces are built on four modes and on their pentatonic and hexatonic versions, almost always in keys comfortable for instruments in D (whistle, pipes, flute) and for the fiddle (G, D, A, E). Roman numerals in minor are relative to natural minor.

Ionian (major)

• Formula 1 2 3 4 5 6 7 — D major: D E F# G A B C#; G major: G A B C D E F#.
• Characteristic note: the leading tone (C# in D), often avoided or passing in the melody.
• Chords: I (D) ii (Em) iii (F#m) IV (G) V (A) vi (Bm).
• Use: most reels, jigs and polkas (e.g. the reel “The Silver Spear” in D, the jig “The Kesh” in G).

Mixolydian

• Formula 1 2 3 4 5 6 b7 — D Mixolydian: D E F# G A B C; A Mixolydian: A B C# D E F# G (the scale of the Highland bagpipe: low G–A–B–C#–D–E–F#–G–high A).
• Characteristic note: b7 (C natural in D): the “ancient,” bright sound of Celtic.
• Chords: I (D) ii (Em) iii° (F#°) IV (G) v (Am) vi (Bm) bVII (C).
• Use: very many reels and hornpipes, bagpipe music (which has the b7 natively).
• Common mistake: harmonizing with A7 (V) where the melody has the C natural: use C (bVII) or Am (v).

Dorian

• Formula 1 2 b3 4 5 6 b7 — E Dorian: E F# G A B C# D; A Dorian: A B C D E F# G.
• Characteristic note: major 6 (C# in E): a “bright” and melancholy minor.
• Chords (relative to natural minor): i (Em) ii (F#m) III (G) IV (A) v (Bm) #vi° (C#°) VII (D).
• Use: reels and jigs in minor (e.g. the slip jig “The Butterfly” in E minor/Dorian; the reel “Drowsy Maggie” in E Dorian), ballads.

Aeolian (natural minor)

• Formula 1 2 b3 4 5 b6 b7 — E Aeolian: E F# G A B C D; B Aeolian: B C# D E F# G A.
• Characteristic note: b6 (C in E): sadness, lament.
• Chords: i (Em) ii° (F#°) III (G) iv (Am) v (Bm) VI (C) VII (D).
• Use: slow airs, laments, some reels.

Pentatonic and hexatonic scales

• Many melodies use 5 or 6 notes: major pentatonic (D E F# A B), hexatonic “gapped scales” (D E F# G A B without the seventh, ambiguous between Ionian and Mixolydian). The “missing” notes make more than one harmonization possible.

How to choose

Ionian for cheerful dances, Mixolydian for “bagpipe” energy and the archaic, Dorian for melancholy, danceable minor, Aeolian for laments. Leave ambiguous the notes the melody avoids: that is the charm of Celtic.

Harmony

Melody first

Celtic dance music was born monophonic: a single melody player or several instruments in unison (heterophony with variants and ornaments). Harmonic accompaniment (guitar, bouzouki, piano, harmonium) came in mainly in the 20th century and with the revival.

Accompaniment principles

• Modal chords: I–bVII–IV (Mixolydian), i–VII–VI (Aeolian), i–IV (Dorian), avoiding the major dominant where the melody has the b7.
• Drones: bagpipes and uilleann pipes have drones (tonic and fifth); guitar in DADGAD and bouzouki with open strings imitate the drone under changing chords.
• “Thirdless” chords (D5, A5, Asus4): compatible with both major and minor and with the ambiguous notes of the melody.
• Harmonic rhythm: 1 chord per bar or per half bar; often the bass stays on the tonic while the upper chords change.
• Countermelodies of bouzouki and guitar (Dónal Lunny, Alec Finn): lines that move against the melody.
• Accompanying piano in “vamp” style (bass–chord) in dance bands (ceili bands).

Celtic pop and film

Pop progressions (I–V–vi–IV, vi–IV–I–V) with pads, strings and multitrack choirs (Enya), but modal melodies and traditional instruments; open harmonies in fourths and fifths, long pedals.

Typical progressions

Rhythm and groove

• Reel: 4/4 or 2/2, nearly straight eighth notes with a slight “lilt” (accent on the first and third quarter notes, push on the upbeat); two parts of 8 bars (AABB).
• Double jig: 6/8 (two groups of three eighth notes), “DUM-da-da DUM-da-da.” Single jig and slide (12/8, Munster) with a quarter note–eighth note figure.
• Slip jig: 9/8 (three groups of three eighth notes), a light dance.
• Hornpipe: 4/4 with strongly uneven eighth notes (close to dotted/swing, 60–67%) and endings with three repeated quarter notes at the end of each part.
• Polka: fast 2/4 (Sliabh Luachra). Mazurka (Donegal) in 3/4 with accent on the second beat. Waltz 3/4.
• Strathspey (Scotland, Cape Breton): slow 4/4 with the Scotch snap (accented sixteenth note + dotted eighth note) and dotted rhythms.
• Lilt and microtiming: the eighth notes are not equal; the groove changes between regions (Clare more relaxed, Sligo more “driven,” Donegal more nervous). Swing in a DAW: 10–20% in reels, 50–60% in hornpipes.

Drums

Percussion in Celtic music

• Bodhrán: Irish frame drum (35–45 cm diameter) played with a double-headed beater (tipper/cipín) and with the free hand behind the skin that changes the pitch and mutes. Relatively modern in dance music (spread in the 1960s by Seán Ó Riada and the Chieftains).
• Bones and spoons: small percussion in triplets and sixteenth notes.
• Military drums and bass drum in Scottish pipe bands (snares with tight rolls, tenor drums, bass drum).
• Feet (step dance, sean-nós dance) as percussion.

How the bodhrán thinks

• Jig: strokes on the three eighth notes of each group with an accent on the first (“DOWN-up-down”), bass on the first beat of the bar, variations with rim strokes and triplets.
• Reel: sixteenth or eighth notes with accents on the first and third quarter notes, “lilt” on the upbeat eighth notes; the pattern follows the melody (phrases of 2 and 4 bars).
• The hand behind the skin creates pitched melodies: pressure for highs, open hand for lows.
• Dynamics: the bodhrán must stay under the melody; in sessions there is only one bodhrán (an unwritten rule).
• Pipe band: snares in unison with figures rich in flams, drags and rolls, synchronized with the pipe phrases.

In Celtic rock and pop

Drum set in 6/8 or 4/4 with kick on the strong beats, snare on 2 and 4 in reels (or on the second pulse in the jig), toms for breaks; in Celtic punk, fast tempos and snare on every beat.

Typical mistakes

Bodhrán too loud or with the same constant pattern throughout the piece; pop drums that ignore the 6/8; rigid quantization that kills the lilt.

Bass

• In the tradition there is no bass: the fundamental is given by the drones (pipes, bagpipes) or by the low register of the guitar/bouzouki.
• Guitar in DADGAD or in open tunings (DADF#AD, CGDGCD) with the thumb on the open low strings (D, A): bass-drone.
• Irish bouzouki (often tuned GDAD or GDAE): bass lines and countermelodies.
• Double bass, electric and fretless bass in modern groups and Celtic rock (Capercaillie, Lúnasa with Trevor Hutchinson on double bass): tonics, fifths, pedals, lines that follow the phrase; in reels, eighth notes on the tonic.
• Synth bass and sub in Celtic pop and soundtracks: long, soft pedals.

Harmonic instruments

• Acoustic guitar (DADGAD or standard, with capo): rhythmic accompaniment in eighth notes (reels) or in groups of three (jigs), open chords.
• Irish bouzouki and cittern: countermelodies, double stops, drones.
• Celtic harp (lever harp, 34–36 strings): airs and pieces by O'Carolan, accompaniment of singing.
• Piano (ceili band, “vamp” accompaniment), harmonium, accordion and concertina (also melodic).
• Uilleann pipes: besides the melody (chanter), they have drones and regulators (keyed pipes the player presses with the wrist for accompanying chords).
• Voicing: open chords with open strings, open fifths, suspended chords; middle register; no thirds in the low register.

Melody and vocals

• Melodic instruments: fiddle (violin tuned GDAE, with its own techniques and ornaments), tin whistle (in D), wooden Irish flute (simple system), uilleann pipes, Highland bagpipe, button accordion and concertina, tenor banjo, mandolin, harp.
• Irish ornaments: cut (very short high note before the main one), tap/strike (very short low note), roll (gruppetto: note–cut–note–tap–note), cran (pipes ornament on low notes), treble (three fast repeated notes with the bow or the tongue), slide (portamento from below).
• Scottish pipe ornaments: grace notes, doublings, throws, birl, taorluath.
• Singing: sean-nós (solo, unaccompanied, melismatic ornaments, free rhythm; the text is as important as the melody), narrative ballads, songs in Gaelic (Scottish puirt à beul: “mouth music” for dancing), work songs (waulking songs). Natural voice, little vibrato, nasal and clear.
• Celtic pop: ethereal female voices with long reverb and multitracks (Enya: dozens of overdubs of her own voice to create “cathedral” choirs), harmonies in thirds and sixths.

Instruments

Fiddle (violin), tin whistle and low whistle, wooden Irish flute, uilleann pipes (chanter, drones, regulators), Scottish Highland bagpipe, smallpipes, biniou and bombarde (Brittany), gaita (Galicia, Asturias), button accordion, concertina, tenor banjo, mandolin, guitar (DADGAD), Irish bouzouki, cittern, Celtic harp, bodhrán, bones, spoons, piano, harmonium, voice; in Celtic rock drums, bass, electric guitar; in Celtic pop synths and pads.

Drum patterns

Synths and sounds

• Jun-6 V — 1980s Celtic pop-style pads: Soft pads with chorus (I and II together), slow attack and long release under multitrack voices and harp: the atmosphere of many Celtic new age records.
• Augmented Voices — Ethereal “cathedral” choirs: Vocal layers on “ah”/“oo” vowels to simulate the multitrack choirs of the Enya style; long reverb and high pre-delay.
• Augmented Strings — Strings for Celtic soundtracks: Slow, warm strings under whistle and uilleann pipes (Horner style): minimal synthetic edge, filter at 8 kHz.
• Mellotron V — Folk-rock flutes and choirs: Tape flutes and choirs of 1960s–70s British folk rock.
• Jup-8 V — Pads and brass for Celtic rock: Wide pads and synth brass for Scottish-style Celtic rock (Runrig, Big Country).

Song structure

The form of dance tunes

• Each tune has two (sometimes three or more) parts of 8 bars: A A B B (32 bars = one “round”).
• The round is played 3 times (sometimes 2 or 4), then you move without a pause to another tune of the same type: the set (e.g. three reels, or jig–jig–reel).
• The change from one tune to the next is a moment of energy: often the rhythm “tightens” and the accompaniment changes.

Airs and songs

• Slow air: free verse, often AABA, rubato rhythm, played by pipes, whistle or fiddle.
• Ballads: strophic, 4–12 verses, optional chorus.
• Sean-nós: unaccompanied verses.

Modern arrangement (revival and beyond)

In Celtic pop: verse–chorus with traditional instrumental interludes.

Mixing and mastering

Sonic goal

Lively unison of the melodic instruments (fiddle, flute, pipes, accordion) with their differences of ornament, clear but low-level rhythmic accompaniment, defined but discreet bodhrán, pub or small-hall space. References: Planxty, Bothy Band, Lúnasa (clean modern productions), Martin Hayes & Dennis Cahill (intimacy), Capercaillie (modern Celtic), Enya (atmospheric pop).

Fiddle

• Condenser mic (or ribbon for a warmer sound) at 50–80 cm above the instrument.
• EQ: high-pass at 150–200 Hz; −2 dB at 400–600 Hz if “boxy”; −1/−2 dB at 2.5–3.5 kHz if shrill; +1 dB at 8–10 kHz for air.
• Compression: 2:1, attack 15–25 ms, release 100 ms, 2–3 dB.
• Panning: L 20–40.

Flute, whistle, low whistle

• Mic at 30–60 cm, angled toward the center of the body and not at the mouthpiece (controlled breath).
• EQ: high-pass at 200–300 Hz (whistle) / 150 Hz (flute); −2 dB at 2–3 kHz if the whistle pierces; the light breath is part of the sound.
• Panning: R 20–40.

Uilleann pipes and bagpipes

• Pipes: mic on the chanter at 30–50 cm + one mic for drones and regulators (at 50–80 cm), or a stereo pair; −2/−3 dB at 2–4 kHz if harsh; drones 6–10 dB below the chanter.
• Highland bagpipe: extremely loud (over 100 dB SPL up close): mics at 2–3 m, dynamics or condensers with a pad; −3 dB at 2–3 kHz.

Accordion and concertina

• Two mics (melody side and bass side) at 30–40 cm; −2 dB at 300–500 Hz; compression 2:1.

Guitar and bouzouki (accompaniment)

• Guitar: mic at the 12th fret at 20–30 cm + a second mic or pickup; high-pass at 80 Hz, −2/−3 dB at 200 Hz, +1 dB at 4–5 kHz for the “drive” of the strumming; compression 3:1 (4–5 dB) for an even rhythm.
• Bouzouki: high-pass at 100 Hz, −2 dB at 1 kHz if metallic; panning opposite the guitar.

Bodhrán

• Mic in front of the skin at 20–30 cm (tipper attack) + possibly a mic behind for the body; EQ: lows 60–90 Hz (+2 dB, controlled), −3 dB at 250–400 Hz, attack +2 dB at 2–4 kHz.
• Compression 4:1, attack 10 ms, release 80 ms, 3–5 dB.
• Panning: center or slightly off to one side.

Voice

• Sean-nós and ballads: condenser at 25–40 cm, high-pass at 80–100 Hz, opto compression 2:1 (2–4 dB), natural room.
• Celtic pop: close voice, compression 3–4:1 + opto, long hall or plate reverb (2.5–4 s, pre-delay 40–80 ms), wide multitrack doubles and choirs (L/R 60–100), dotted-eighth-note delay.

Buses and groups

Melodic, accompaniment, percussion, vocals; a shared hall reverb (0.8–1.4 s) and a long one for the airs and pop.

Sidechain

Only in Celtic pop/electronic (kick → pad/bass, 2–3 dB).

Master

• Acoustic trad: −16/−12 LUFS integrated, true peak −1 dBTP, LRA 5–10 LU.
• Celtic rock/pop: −11/−9 LUFS.

Common mistakes

• Melodic instruments that mask each other (same 1–4 kHz band): differentiate them with panning and light EQ.
• Guitar too loud, covering the ornaments.
• Bodhrán with swollen lows and an overly present pattern.
• Quantization and pitch correction that eliminate the micro-variations of the unison.

Reference tracks for the mix

• Planxty — The Well Below the Valley (1973).
• The Bothy Band — The Kesh (The Bothy Band, 1975).
• Lúnasa — Otherworld (album, 1999).
• Capercaillie — Coisich a Rùin (1992).
• Enya — Orinoco Flow (1988).

Reference listening

• Turlough O'Carolan — Carolan's Concerto (XVIII secolo)
• The Chieftains — The Chieftains 4 (1973)
• Planxty — The Well Below the Valley (1973)
• Alan Stivell — Renaissance de la harpe celtique (1971)
• The Bothy Band — The Kesh (1975)
• Clannad — Harry's Game (1982)
• The Pogues — Fairytale of New York (1987)
• Enya — Orinoco Flow (1988)
• Capercaillie — Coisich a Rùin (1992)
• Bill Whelan — Riverdance (1994)
• James Horner — Main Title (Braveheart, 1995)
• Martin Hayes & Dennis Cahill — The Lonesome Touch (1997)