Harmonica

What it is

A small free-reed instrument played with the mouth: air blown or drawn across tuned brass reeds. Also called blues harp, mouth organ or French harp. The 10-hole diatonic (Richter-tuned) is the common blues and folk instrument; the chromatic uses a slide for semitones; the tremolo harmonica has two slightly detuned reeds per note.^3,10

Range

C3 to C7⁶131 Hz – 2.09 kHz

the bottom from the 16-hole chromatic; the top from a C diatonic (commonly stated, not confirmed)

• 10-hole diatonic in C:
• 12-hole chromatic: ⁶
• 16-hole chromatic: ⁶
• 10-hole diatonic (Richter) in C: Wikipedia: a C harp starts on middle C (C4) at hole 1 blow and there is 'a three-octave distance between 1 and 10 blow', so hole 10 blow is C7 (my arithmetic). Harps in G, Ab, A, Bb or B start below middle C; Db to F# start above it.⁷

The sound

Reeds in cells vibrate when air passes through; the mouth and hands shape the sound. Hand shape sends the sound forwards, to the side, down or past the player's ear, depending on the player.³

Where the sound goes

From the cupped hands, not a fixed direction. SOS shows photographs of how different hand cupping sends the main sound up, down or to one side, so the engineer must find where it goes (even walk round the player).³

About the range

The standard diatonic gives 19 different notes across three octaves in one key; chromatics cover three or four octaves. A 12-hole chromatic's lowest note is middle C (C4) in standard solo tuning and a 16-hole starts an octave lower, at C3. A C-key 10-hole diatonic starts at C4 and tops out near C7 (estimate; commonly stated, not confirmed in a page I opened).^3,6

How loud

Sound pressure level measurements as published. Different kinds of figure (a playing level, a peak, a dose at the player's ear) can't be compared with each other, and neither can figures at different distances.

Two Japanese articles on a silenced harmonica give about 85 dB and 80-90 dB for a 10-hole harmonica played normally (distance not stated, secondary). Harmonica mics (such as the Audix Fireball) are built for high SPL; players are loudest when bending notes down.³

Recording it

Recording, acoustic (pop, jazz, folk, classical):

• A stand-mounted condenser is the natural start. Brendan Power uses "a good quality studio mic like a Neumann U87", one to two feet away "to give it some air". SOS's audio examples used a Neumann TLM 103, AKG C214 and AKG C1000S condensers 6-8 in away; at six inches the sound is full and focused, and at a foot or more it is airier with more room.
• Set the mic low, below nose level or chin, to avoid nasal breath noise; pointing it up into the hand aperture picks up more harmonica and less breathing. Move it a few inches off the air stream to clear windiness; small-diaphragm mics tolerate off-axis placement better.
• Producer Gareth Williams: for accompaniment back off or use a pencil mic plus a room mic; for a lead go close with a large-diaphragm, as on a lead vocal.
• Bartlett: a flat condenser or mini mic about 8 in away.

Recording, amplified (blues, rock): the player holds a bullet mic cupped with the harmonica into a guitar amp and the amp is miked like a guitar amp. Cupping gives a treble roll-off, a bass and low-mid boost and a honky peak near 1 kHz. Keith Parker uses a late-1960s Shure Spher-O-Dyne; Lee Sankey carries crystal, controlled-reluctance and controlled-magnetic mics and matches them to the amp. The Shure 520 "Green Bullet" (1949) fits the cupped hand, and the original high-impedance version worked with tube guitar amps; the current 520DX has a modern dynamic element voiced to sound like the original. A forum thread suggests an SM57 on the amp for more bass, an SM58 for more mids.^3,2,4,1

Mics i

1. Shure SM57 2 sourcesClose, handheld
2. Shure SM58 2 sourcesClose, handheld
3. Shure 520DX "Green Bullet" 2 sources, 1 from a mic makerHandheld

On stage

A handheld cardioid dynamic for a dirty sound, or plug it into a guitar amp and mic the amp.²

Problems to watch

Breath and nose noise; feedback with a cupped mic and amp (a tight seal reduces it); vintage mics are high impedance and need a high-Z input or DI; level jumps on note bends and on the high register; rings and jewellery clicking on the case, and a noisy chromatic slide. SOS suggests a high-pass at 150-200 Hz.³