Microphone Basics — Dynamic, Condenser, Direction
A microphone really decides what it listens to, not what it costs
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The most important sentence in microphone basics: it is not "recording sound", it is "listening". A microphone's character is decided by two things — what it listens to (directionality) and how it listens (transduction).
Two technical routes: dynamic and condenser
| Dynamic | Condenser | |
|---|---|---|
| Principle | a coil moves in a magnetic field | plate spacing changes with sound pressure |
| Sensitivity | lower | high |
| Needs phantom power | no | yes |
| High-frequency ceiling | lower | high |
| Rejects room noise | well | less well |
| Transient response | slightly slower | fast |
These are not "cheap vs expensive"; they are two trade-offs.
The second example shows the practical consequence: breath and fine dynamics in choral recording disappear on a small dynamic mic — not simply because sensitivity is lower, but because the dynamic's ceiling filters them out entirely.
Directionality: what the microphone actually decides
More important than "which type" is another dimension:
- Omnidirectional — hears all around. Good for quiet indoor instruments, and it also hears the whole room;
- Cardioid — front, rejecting the rear. The default for live voice and instruments, because it rejects noise behind;
- Figure-of-eight — front and rear, rejecting the sides. Good for picking up across a group;
- Shotgun — very narrow, a line. For distant pickup, which also makes it extremely sensitive to distance.
The third example makes the point: directionality decides which part of the room it hears. So in a studio, "which mic" is half the same question as "where is it, facing which way".
A practically more important choice: distance
Beginners think the microphone model matters most. In practice distance matters more.
- Close (10–20 cm) → direct, full, immediate, almost no room;
- Medium (40–60 cm) → natural, with a little room;
- Far (over 2 m) → room-dominated, detail lost.
The same microphone close sounds "right at your mouth"; far away it sounds "someone singing in a room". That usually outweighs swapping microphones.
The first example is the converse: on stage the level is already adequate, so a dynamic mic close to the source is the stable choice — because nothing weak needs picking up.
An easily missed directional issue
Microphones have an orientation. A polar pattern says which direction is most sensitive, but a microphone's "front" does not necessarily coincide with the direction the performer faces.
The practical consequence: the performer's facing changes the timbre. Same note, same microphone, turn the performer slightly and the timbre changes — because the angle and the reflection path to the mic changed.
Listen: what distance changes
Below is the same set of notes used in the other audiolabs on this site. Imagine two takes: one almost touching (full, no space), one several metres off (less detail, obvious room). You will notice that what changes is *space*, not pitch.
Next
- What it listens to: Timbre.
- What decides timbre: Timbre.
- The recorder's job: roles in the studio.
- Mixing: Dynamics.
Listen in the library
All tracks from midicn-lib — inline badge is the license tier (C1 commercial / C2 non-commercial / C3 study only).
Sources
- 本文为麦克风工作原理的通识性介绍；具体型号参数、测量方法与选购建议不在本文范围
- 涉及的曲目均标注来源与许可档位，可在线试听
Used for fact-checking only; all prose is original.