1 / 9

Comprehensive Overview of Microphone Performance Specifications and Measurement Standards

This text provides an in-depth examination of key performance specifications for microphones, including directional properties, frequency response measurements, output sensitivity, source impedance, and equivalent self-noise levels. It highlights the importance of measuring conditions, such as distance, and discusses microphone designs, including low impedance standards and sensitivity ratings. Additionally, it covers distortion characteristics and dynamic range, presenting the relevant metrics required for effective microphone performance evaluation in various applications.

hedy
Télécharger la présentation

Comprehensive Overview of Microphone Performance Specifications and Measurement Standards

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Microphone Measurements, Standards, and Specifications Eargle, Ch. 7

  2. Primary Performance Specifications • Directional properties • Data in polar form, or set of on- and off-axis frequency response measurements. • Frequency response measurements • Usually at 0° axis, and 90° (plus others) • Output sensitivity • Often stated at 1 kHz, measured in free field • Output source impedance • Equivalent self-noise level • Maximum operating SPL for a stated % of THD

  3. Frequency Response • Should always state measuring distance (to access proximity effect), or assume 1 meter. • Can be shown with tolerance limits, but if so, not the measurement of a specific, actual mic • Sometimes, other distances included to show proximity effect. • Response with low-cut (high-pass) filter

  4. Polar Response • Eargle states that due to microphone symmetry, hemispherical plots are sufficient (180°). • Most manufacturers include full sphere.

  5. Mic Sensitivity • Pressure Sensitivity • Output rms in response to 1 kHz, 94 dB SPL, in free field. • Output Power Sensitivity • Measure the output when mic is loaded with an impedance equal to its own internal impedance

  6. Microphone Source Impedance • Almost all professional mic’s today are low impedance. • Typically 50 to 200 ohms • Typical input load impedance in 2k to 5k ohm range. • Output impedance rating of little consequence.

  7. Normal Mic Design Sensitivity • Reference output sensitivity matches intended use of microphone • Mic’s intended for strong sound sources will need less output sensitivity. • Distant pickups require more. • Close-in (2 - 8 mV/Pa) • Distant (7 - 20 mV/Pa)

  8. Mic Equivalent Self-Noise Level Rating • Stated in dB(A), representing the signal that would be picked up by an ideal mic in the rated acoustical sound field. • Capacitor mics: 7 - 15 dB(A) • Tube models: 17 - 23 dB(A) • Capacitor mics are 10 - 12 dB greater than EIN of good console or preamp. • Dynamic 10 - 12 dB less than capacitor.

  9. Distortion and Dynamic Range • Studio mics: 0.5% THD at 1 kHz. • Require signal levels in the 130 to 140 range. • Dynamic Range is range specified in dB between noise floor and 0.5% THD level.

More Related