| Equivalent noise level |
| The output signal of every microphone always includes a low noise signal in addition to the useful signal. In order to illustrate the extent of the noise voltage, it is given as a fictitious sound pressure level. In an ideally noise-free microphone, a sound pressure level of this magnitude would result in an output voltage of the magnitude of the noise. Self-noise is measured and weighted either in accordance with CCIR 468-3 or – in order to assimilate the measured result with the listening impression of the human ear – in accordance with DIN/IEC 651 (so-called A-weighted). Studio condenser microphones generally have an equivalent noise level of between 20 and 30 dB (CCIR) or between 10 and 20 dB(A). |
| Equivalent noise level weighted as per CCIR 468-3 |
| The output signal of every microphone always includes a low noise signal in addition to the useful signal. In order to illustrate the extent of the noise voltage, it is given as a fictitious sound pressure level. In an ideally noise-free microphone, a sound pressure level of this magnitude would result in an output voltage of the magnitude of the noise. Self-noise is measured and weighted either in accordance with CCIR 468-3 or – in order to assimilate the measured result with the listening impression of the human ear – in accordance with DIN/IEC 651 (so-called A-weighted). Studio condenser microphones generally have an equivalent noise level of between 20 and 30 dB (CCIR) or between 10 and 20 dB(A). |
| Frequency response (microphone) |
| The frequency response of a microphone is given within the limits defined by the manufacturer. In studio condenser microphones it is generally within the range of between 20 Hz and 20 kHz. |
| Min. terminating impedance |
| Impedance at which the connected unit meets the specified technical data. If the unit is connected to a lower impedance, it will usually have a lower output voltage or a greater distortion. |
| Nominal impedance |
| See impedance. |
| Pick-up pattern |
| Also known as polar pattern, directivity. According to their acoustic design, microphones differ in their sensitivity towards sound from different directions. Pressure microphones have a sensitivity that is largely independent of direction (omni-directional pick-up pattern). Pressure gradient microphones have the pick-up patterns wide cardioid, cardioid, super-cardioid or figure-of-eight. Interference microphones can be used to achieve a further concentration of the pick-up pattern (lobar pick-up pattern). As a special case, dummy head microphones achieve the pick-up pattern of the human ear/head (dummy head stereo). |
| Power supply |
| Description of the power source used for powering a unit, for example mains, battery, rechargeable accupack, etc. |
| Sensitivity in free field, no load (1kHz) |
| Voltage measured at the unloaded output of a microphone which is exposed to a sound pressure of 1 Pa and a frequency of 1 kHz in an anechoic chamber. |
| Transducer principle |
| Two transducer principles have become established for the conversion of electric energy into mechanical energy: electrodynamic and electrostatic transducers, whereby the latter is only to be found in audiophile systems, due to their relatively high manufacturing costs. Electrodynamic transducers basically consist of a ring-shaped permanent magnet and an oscillation coil, which is fixed to the receiver diaphragm. When an audio-frequency alternating current is passed through the oscillation coil, it is caused to vibrate in accordance with the audio-frequency alternating current, thus causing the diaphragm to vibrate in the same way. |
