Capture of Sound · Edexcel 1.2 · A-Level Music Technology

Polar patterns: what a microphone rejects.

Drag the source round the microphone, or in close, and listen. The pattern decides what you hear. The diagram is the exam's own: read the level off it in dB.

Source

Polar diagram · Cardioid

drawn at

drag round for angle, in for distance · hover or tap a ring or an angle to read it

pattern at 250 Hz at 6 kHzopen at the sides, a null at the rear

At 250 HzThe pattern as a spec sheet prints it for a low frequency. Every ring inward is 5 dB quieter than on axis; hover a ring to read it. Switch to 6 kHz to see the same microphone at a high frequency.

Angle · ← →

30°

Distance · ↑ ↓

40 cm

Level · 250 Hz

-0.6 dB

Tone · 6 kHz

full, on axis

The shape in the room · Cardioid

The polar diagram is this shape seen from above, cut through at the height of the capsule. It is the same all the way round the microphone’s axis, so that one slice says everything. Press From above and watch it become the diagram.

Frequency response

hover or tap an axis

on-axis, 1 mnearfield, 5 cmyour source

The two printed curves are the spec sheet's, each measured in one fixed position: on axis at a metre, and nearfield, which means close in, at 5 cm. The blue one is your source, where you have put it. Bring it to either position and it lands on the printed curve.

Off axis is quieter and duller. The whole curve drops by the level the polar diagram gives, and the top end falls further as the pattern narrows with frequency. It is never bassier: that is the proximity effect, a matter of distance, not angle.

Cardioid · A = 0.5 · B = 0.5

An even split, A = 0.5 and B = 0.5: a heart shape, most sensitive in front with one deep null directly behind. Still fairly open at the sides, about 6 dB down at 90°.

Use it for. The close-mic default: a lead vocal, a guitar cabinet, anything with the room or the monitors behind it.

In the exam. Rejects the rear, not the sides. At 90° the papers accept −5 to −7 dB (2026 A2 Q3a). “Picks up from the front and sides” was the E-grade answer in 2019 Q4e; the A grade read the diagram.