Same chord. Five different acoustic body shapes. Hear the bass response shift.

Pick a body shape. The same open E minor chord strums through that body's typical resonance profile — smaller bodies (parlor) put more energy into the midrange, bigger bodies (jumbo) push harder into the bass. The classical profile uses softer waveforms and slower attack to imitate the nylon-string voice.

Software synthesis with body-resonance peaking filters tuned to each body shape's typical Helmholtz frequency. A real instrument's tone depends on the specific wood, the bracing pattern, the age of the soundboard, and the room it's played in — but the bass-response differences between body sizes are reproducible enough to hear here.

Martin invented most of these shapes

Christian Frederick Martin Sr. emigrated from Germany to New York in 1833 and started building guitars in his small shop. The company moved to Nazareth, Pennsylvania, in 1839, where it has built guitars continuously for the last 187 years. The current operation is the sixth generation of the same family.

By the late 19th century Martin had created a standardised system of body sizes labelled from largest to smallest — 1, 2, 2½, 3, and 5. The "0" appeared in 1854 (initially even smaller), and then the "00," "000," and finally the "dreadnought" sizes followed as Martin progressively scaled UP, not down. The size labels are confusingly inverted: a 5 is smaller than a 1, and a 0 is bigger than both. By 1916 they had introduced the giant dreadnought, named after HMS Dreadnought, the Royal Navy battleship that revolutionised naval warfare in 1906 — Martin wanted to signal that this was the biggest, loudest guitar going.

The 1929 OM (Orchestra Model) was Martin's attempt to compete with Gibson archtops in the orchestral plectrum-guitar work of the era. It put a 14-fret neck on a 000 body and added a longer 25.4-inch scale — and accidentally became the fingerstyle standard for the rest of the 20th century. Every modern body-shape category — parlor, 000, OM, Grand Concert, dreadnought — came out of the Martin catalogue or was a direct response to it. Gibson's 1937 jumbo, Taylor's 1994 Grand Auditorium, every boutique luthier's modern shapes — all of them are positioned relative to Martin's sizes.

Why body size determines bass response

An acoustic guitar body is essentially a Helmholtz resonator — the air enclosed inside the body vibrates at a specific natural frequency determined by the volume of the cavity and the size of the soundhole. Bigger cavity, lower resonant frequency. A parlor body has a small internal volume and resonates around 280 Hz; a dreadnought is larger and resonates around 160 Hz; a jumbo is larger still and resonates around 130 Hz.

When you pluck a string, the soundboard vibrates, the enclosed air vibrates with it, and the body's resonant frequency is boosted in the resulting tone. So bigger-body guitars produce more energy in the low frequencies — more bass — and smaller-body guitars produce more energy in the midrange. This is not a matter of which sounds "better." It is a trade-off: the dreadnought has the bass that helps it sit prominently in a band mix or accompany a singer; the parlor has the midrange clarity that lets every note of an intricate fingerpicked passage be heard.

The widget above models this with a peaking filter set to each body's typical Helmholtz frequency. Switch between parlor, OM, dreadnought, and jumbo and the bass response shifts audibly — the chord is the same, but where the energy concentrates is different.

The wood choices that colour the sound

Soundboard / top. The single most acoustically important component. Almost always Sitka spruce (bright, strong, the all-purpose standard since the 1920s) or western red cedar (warmer, faster-responding, favoured for fingerstyle and classical playing). Adirondack spruce was used on most pre-war Martins and Gibsons and is still considered the premium choice for high-end vintage-style builds.

Back and sides. Shape the tonal colour. Rosewood (Indian rosewood since the 1970s, Brazilian rosewood on pre-1970 high-end builds) produces a rich complex sound with strong bass and overtones — the D-28 sound. Mahogany is woodier, more midrange-focused, and punchier — the D-18 sound, the bluegrass standard. Maple is bright and articulate with quick decay — the Gibson SJ-200 standard. Koa (Hawaiian, used since the 1910s) is warm and balanced, sits between rosewood and mahogany.

Neck, fingerboard, bridge. Necks are almost always mahogany — light, stable, comfortable. Fingerboards and bridges are ebony (denser, brighter) or rosewood (slightly warmer). These choices matter much less to overall tone than the top and back-and-sides do.

The five in the widget, in depth

The other five

Specialised shapes, doubled-string variants, and the metal-resonator family.

All 10 types at a glance

Sorted by year of introduction. Six rows lead with Martin or the Spanish tradition that Martin was modelled on.

Six players who defined what each body shape sounds like

Robert Johnson (1911–1938) — Parlor / Kalamazoo KG-14. The pre-war Delta blues musician who recorded just 29 songs in two sessions (1936, 1937) before dying at 27. Played a parlor-sized Kalamazoo (Gibson budget brand) and Gibson L-1. Every modern Delta-blues parlor revival traces back to those recordings.

Bob Dylan (b. 1941) — Martin D-28 Dreadnought. The folk-rock dreadnought sound of "The Times They Are a-Changin\'," "Blowin\' in the Wind," and effectively the entire 1960s American protest-music canon. The instrument made the dreadnought the visual symbol of the singer-songwriter for the next sixty years.

Eric Clapton (b. 1945) — Martin 000-42. His MTV Unplugged performance in 1992 made the 000 / OM body the modern singer-songwriter standard. The album sold 26 million copies and triggered a decade of acoustic-only sessions across the industry. Every fingerstyle player who started in the 1990s and 2000s owns a 000 or OM because of that performance.

Tony Rice (1951–2020) — Martin D-28 (the "Holy Grail," ex-Clarence White). The defining bluegrass flatpicker of the late 20th century. Played a 1935 Martin D-28 with a custom enlarged soundhole that previously belonged to Clarence White (The Byrds). His instrumental records on the Rounder label set the technical standard for bluegrass lead playing.

Andrés Segovia (1893–1987) — Hauser / Ramírez Classical. The Spanish classical guitarist who, almost single-handedly between 1910 and 1960, elevated the classical guitar from a folk instrument to a respected concert instrument. Played Hermann Hauser I and Manuel Ramírez instruments. Commissioned new works from major 20th-century composers (Villa-Lobos, Castelnuovo-Tedesco, Ponce, Rodrigo) that became the modern classical repertoire.

Tom Petty (1950–2017) — Rickenbacker 360/12, Gibson Dove Jumbo. The 12-string electric on "The Waiting" and "Free Fallin\'" is a Rickenbacker; the acoustic 12-string on the same songs is often layered with a Gibson Dove jumbo. The combination defined what 12-string American rock sounds like — bright shimmering chime on top of a giant strummed jumbo bed.

Continue exploring