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# Basics of microphone

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Assignment 1 for coursera course 'Introduction to Music Production' by Loudon Stearns

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### Basics of microphone

1. 1. -Samhita Shiledar
2. 2. A bit about myself  I’m Samhita Shiledar from India! I recently completed my Chemical engineering and working in same field now. I play piano and sing Indian Classical Music. This lesson is for week 1 of Introduction To Music Production at Coursera.org My ppt is about overview of various characteristics of microphones and few important types. Hope you guys enjoy ;)
3. 3. Microphone is an INTERNAL TRANSDUCER that converts SOUND(pressure waves in air) into ELECTRIC SIGNAL(voltage variations)
4. 4.  Way a microphone responds to different frequencies.  Some frequencies are exaggerated and others are attenuated (reduced)
5. 5. Frequency response may be less informatively stated textually like so: "30 Hz–16 kHz ±3 dB". This is interpreted as meaning a nearly flat, linear, plot between the stated frequencies, with variations in amplitude of no more than plus or minus 3 dB.
6. 6. Which frequency response curve is IDEAL?  The x axis shows frequency in Hertz, the y axis shows response in decibels  A higher value means that frequency will be exaggerated, a lower value means the frequency is attenuated.  An ideal "flat" frequency response means that the microphone is equally sensitive to all frequencies. In this case, no frequencies would be exaggerated or reduced .
7. 7.  Polar pattern indicates how sensitive it is to sounds arriving at different angles about its central axis  Some microphones pick up sound equally from all directions, others pick up sound only from one direction or a particular combination of directions.
8. 8. Captures From All Directions Uses: Capturing ambient noise; Situations where sound is coming from many directions; Situations where the mic position must remain fixed while the sound source is moving.
9. 9. Few tips Although omnidirectional mics are very useful in the right situation, picking up sound from every direction is not usually what you need. Omni sound is very general and unfocused - if you are trying to capture sound from a particular subject or area it is likely to be overwhelmed by other noise.
10. 10. Cardioid  Sound is picked up mostly from the front, but to a lesser extent the sides as well.  Uses: Emphasising sound from the direction the mic is pointed whilst leaving some latitude for mic movement and ambient noise e.g.handheld mics
11. 11. Hypercardiod  Very directional and eliminates most sound from the sides and rear.  Uses: Isolating the sound from a subject or direction when there is a lot of ambient noise; Picking up sound from a subject at a distance.
12. 12. Supercardoid Similar to a hyper-cardioid, except there is more front pickup and less rear pickup.
13. 13. While any pattern between omni and figure 8 is possible by adjusting their mix, common definitions state that a hypercardioid is produced by combining them at a 3:1 ratio, while supercardioid is produced with a 5:3 ratio
14. 14. Bidirectional  Uses a figure-of-eight pattern and picks up sound equally from two opposite directions.  Uses: One possibility would be an interview with two people facing each other (with the mic between them).
15. 15. Shotgun Microphones small lobes of sensitivity to the left, right, and rear but are significantly less sensitive to the side and rear than other directional microphones. USES:television and film sets, in stadiums, and for field recording of wildlife.
16. 16. 3.The Dynamic Range Of A Microphone
17. 17.  The difference in SPL between the noise floor and the maximum SPL. for example "120 dB", it conveys significantly less information than having the self-noise and maximum SPL figures individually.
18. 18. 4.Sensitivity
19. 19.  Indicates how well the microphone converts acoustic pressure to output voltage.  A high sensitivity microphone creates more voltage and so needs less amplification at the mixer or recording device.
20. 20. 5.Self-noise Or Equivalent Noise Level
21. 21.  The sound level that creates the same output voltage as the microphone does in the absence of sound.  Represents the lowest point of the microphone's dynamic range, and is particularly important should you wish to record sounds that are quiet.
22. 22. 6.Proximity Effect
23. 23.  Proximity effect is a change in the frequency response of a microphone, having a directional pickup pattern, that produces an emphasis on lower frequencies.  It is caused by the use of ports to create directional polar pickup patterns
24. 24. TYPES OF MICROPHONES
25. 25. A lightweight diaphragm, usually made of plastic film, is attached to a very small coil of wire suspended in the field of a permanent magnet. When a sound causes the diaphragm to vibrate, the whole assembly works as a miniature electricity generator, and a minute electric current is produced.
26. 26. Condenser Microphones A capacitor has two plates with a voltage between them. In the condenser mic, one of these plates is made of very light material and acts as the diaphragm. The diaphragm vibrates when struck by sound waves, changing the distance between the two plates and therefore changing the capacitance.
27. 27. Ribbon Microphones  Ribbon microphones use a thin, usually corrugated metal ribbon suspended in a magnetic field. The ribbon is electrically connected to the microphone's output, and its vibration within the magnetic field generates the electrical signal.
28. 28. PZM Microphones  Pressure Zone Microphones  A small condenser microphone is mounted face-down a short distance from the reflective boundary plate. This creates a pressure zone between the plate and the mic. The microphone detects changes in this pressure zone, rather than the conventional method of detecting changes in the surrounding air pressure (i.e. sound waves).
29. 29. COMPARISON
30. 30. CHARACTERISTI C CONDENSER DYNAMIC RIBBON PZM CAPTURES ALL FREQUENCIES SPECIFIC RANGE OF FREQUENCIES ALL FREQUENCIES SPECIFIC RANGE OF FREQUENCIES SENSITIVITY HIGH LOW HIGH HIGH PHANTOM POWER REQUIREMENT YES NO YES NO ADRESSING SIDE ADRESSED FRONT ADRESSED FRONT ADRESSED TYPICAL POLAR PATTERN OMNIDIRECTIO NAL CARDOID BIDIRECTIONAL CARDOID OR SUPERCARDOID UPPER FREQUENCY RESPONSE LIMIT 20kHz 16kHz
31. 31. CHARACTERIS TIC CONDENSER DYNAMIC RIBBON PZM USES Dynamic mics are useful when the sound source is close and reasonably loud, and where the sound is predominantly bass or mid- range. Capacitor mics work well in most situations and have sufficient sensitivity to pick up quieter or more distant sounds properly. Used while recording from Amplifier In the pressure zone microphone, sound waves are always in phase and there is no interference. COMMON APPLICATIONS In recording studios On stage, ideal for recording drums and loud amplified instruments In recording studios, favoured by classical and acoustic recordists. Conference rooms, podiums, lecterns and other installed- sound uses. SOME EXAMPLES OF MODELS Neumann U87, AKG C414, Oktava MK219 Sure SM57, Sure SM58Beta, Electrovoice RE20 Coles 4038, Beyerdynamic M130. Audio-Technica PRO44, Audio- Technica ATR4697
32. 32. FREQUEMCY RESPONSE Condenser Mic Dynamic Mic Ribbon Mic PZM Mic
33. 33. MORE MIROPHONE TYPES  Carbon microphone  Piezoelectric microphone  Fiber optic microphone  Laser microphone  Liquid microphone  MEMS microphone  Electret Microphone  Crystal microphones
34. 34. References  http://www.planetoftunes.com/record/microphones.htm  http://www.soundonsound.com/sos/1995_articles/jun95/microphones .html  http://www.soundonsound.com/sos/apr98/articles/mic_types.html  http://electronics.howstuffworks.com/gadgets/audio- music/question309.htm#page=10  https://en.wikipedia.org/wiki/Microphone#Ribbon_microphone  http://www.planetoftunes.com/record/microphones.htm  file:///F:/New%20folder/Module%202%20Microphones%20Main%20 Module%20Text%20and%20Check%20Questions%20(1).htm  http://www.fullcompass.com/brand/AT/PZM-PCC-Boundary-Surface- Microphones.html  F:New folderModule 2 Microphones Main Module Text and Check Questions (1).htm
35. 35. THANK YOU! 