Nota berkenaan Methods of Sound recording.pptx

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1. 3 .3 Methods of sound recording and reproduction

2. Monaural(mono) recording and reproduction Stereophoic(stereo)recording and reproduction Surround recording and reproduction

3. Monaural(mono) recording and reproduction Monaural or monophonic sound reproduction is intended to be heard as if it were a single channel of sound perceived as coming from one position

4. In mono, only one loudspeaker is necessary, but, when played through multiple loudspeakers or headphones, identical signals are fed through each of the wires into each speaker, resulting in the perception of a one-channel sound, which "images" in one sonic space between the speakers

5. Applications Mono sound is preferred in radiotelephone communications, telephone networks, and radio stations dedicated to talk shows and conversations, public address system, hearing aids.

6. Cost - Less expensive for recording and reproduction Recording - Easy to record, requires only basic equipment Key feature -Audio signals are routed through a single channel Channel - 1

7. Monaural sound has been replaced by stereo sound in most entertainment applications. However, it remains the standard for radiotelephone communications, telephone networks, and audio induction loops for use with hearing aids. A few FM radio stations, particularly talk radio shows, choose to broadcast in monaural, as a monaural signal has a slight advantage in signal strength over a stereophonic signal of the same power.

8. Stereophonic (stereo) recording and reproduction Stereo recording  is a technique involving the use of two microphones to simultaneously record one instrument.  The mono signals from each microphone are assigned to the left and right channels of a stereo track to create a sen s e o f width in the recording .

9. The stereo effect is created in this technique from the slight difference in sound between the left and right channels of the  studio monitors .  This difference in sound is observed in the following two ways: Difference in timing  – By placing the microphones at different locations, the sound from the instrument will arrive at each microphone at a slightly different time.  A difference of just a few milliseconds is enough to create a stereo effect. Difference in frequency balance  – By angling the microphone in different directions in relation to the instrument, each microphone will pick up a slightly different balance of frequencies.  The greater the angle, the more exaggerated the stereo effect will be . When one mic is heard through the left monitor, and the other mic through the right, it creates a pleasant sense of width that is absent in a mono recording.

10. The 5 Most Useful Techniques to Know Here is a list of the 5 most useful stereo recording techniques. ( A/B Stereo Recording, X/Y Stereo Recording, ORTF Stereo Recording, Blumlein Pair, Mid/Side Stereo Recording) the type of mic required, (including the  microphone polar pattern ) how to position them for recording how to mix the two signals together how it should sound once completed

11. Surround recording and reproduction Surround sound works because multiple audio channels are received through speakers that are positioned at various locations in the room. This is programmed into the source and the sound tracks are decoded when the source is played.

12. Surround sound adds realism and a new field of depth to your listening experience. This is accomplished not only because you have more speakers for output, but because the sound recording itself contains more audio channels.

13. Applications Though cinema and soundtracks represent the major uses of surround techniques, its scope of application is broader than that as surround sound permits creation of an audio-environment for all sorts of purposes. Multichannel audio techniques may be used to reproduce contents as varied as music, speech, natural or synthetic sounds for cinema, television, broadcasting, or computers.

14. Creating surround sound The first and simplest method is using a surround sound recording technique—capturing two distinct stereo images, one for the front and one for the back or by using a dedicated setup. A second approach is processing the audio with psychoacoustic sound localization methods to simulate a two-dimensional (2-D) sound field with headphones. A third approach, based on Huygens' principle, attempts reconstructing the recorded sound field wave fronts within the listening space; an "audio hologram" form. One form, wave field synthesis (WFS), produces a sound field with an even error field over the entire area.

15.  For each one, I’ll explain: the type of mic required, (including the  microphone polar pattern ) how to position them for recording how to mix the two signals together how it should sound once completed Let’s start off with the simplest and most common of the five techniques:

16. 1 . A/B Stereo Recording Mics used : Two omnidirectional mics , usually small diaphragm condensers Positioning : Point both mics toward the instrument , at a distance of a foot, and spaced two feet apart. When experimenting with this technique ,  try making adjustments to both the distance of the mics  from the instrument , as well as the distance of the mics from each other.

17. How to mix the signals :  The mono signals from each microphone are assigned to the left and right channels of a stereo track to create a sense of width in the recording. How it should sound : The stereo image is created because of the time of arrival at each microphone is slightly staggered.  The frequency balance is different as well, which will provided an added level of stereo width. The downside of A/B stereo recording is that because of the timing offset between each microphone, you will be likely to have issues with phase cancellation when combining the stereo signal to mono.

18. 2 . X/Y Stereo Recording Mics used : Two directional mics , usually small diaphragm condensers Positioning : at an angle between 90-135 degrees so that their capsules coincide at a single point.  The wider the angle, the wider the stereo image. How to Mix the Signals : (same as A/B stereo recording) How it should sound : Compared to A/B stereo recording, this technique will have  less  of a stereo effect.  The reason is that since both microphones are positioned at the same point in space, there will be no differences in timing. The entire stereo effect will be created from the differences in frequency balance.  The upside to this is there are no issues with mono phase cancellation either.

19. 3 . ORTF Stereo Recording Mics used : Two directional mics , usually small diaphragm condensers Positioning : Spread outward at an angle of about 110 degrees, with the capsules spaced 17cm apart. How to mix the signals : (same as A/B stereo recording) How it should sound : The technique is basically a combination of the previous two.  The microphones are physical spaced apart, like with A/B recording, which will yield a wider stereo image.  Then it uses directional mics , like with X/Y recording, so it should pick up less of the ambient room sound.

20. 4 . Blumlein Pair Mics used : two figure 8 (bi directional) mics Positioning : (same as X/Y technique) How to mix the signals : (same as X/Y technique) How it should sound :  Compared to the X/Y technique , the Blumlein Pair technique captures a greater portion of the room sound and adds a bit more ambience to the stereo image, thanks to the use of the figure 8 mics .

21. 5 . Mid/Side Stereo Recording Mics used : One small diaphragm condenser mic – either cardioid OR omnidirectional. One large diaphragm condenser mic – MUST BE FIGURE 8 Positioning : The figure 8 mic is placed sideways  at a 90 degree angle from instrument.  This mic will record sound on both sides and will function as the “side” in the term mid/side . The other mic is positioned on top or below the figure 8 mic, and is pointed directly toward the instrument.  It will function as the “mid” in the term mid/side.

22. How to mix the signals : This part is complicated.  Follow the steps carefully. Duplicate the “side” channel Reverse the polarity of the duplicated channel Combine the two side channels onto one stereo track Mix in the mid channel with stereo side channels to adjust the width. The greater level of the sides compared to the mid, the greater the stereo width.

23. How it should sound :  Mid side recording may be complicated, but it offers all the advantages of the other 3 techniques , without the downsides . It offers the added stereo width of the A/B technique It offers the mono compatibility of the X/Y technique And it allows you (if you want) to increase the room ambiance to something resembling the Blumlein Pair technique.