Mikes - The Sound Recorder and Microphone The MicrOphone l...

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Unformatted text preview: The Sound Recorder and Microphone - The MicrOphone l j Microphone Types There are three basic types of microphones in film use. Dynami moving-coil microphones are the standard equipment used by mu performers, amateur recordists and many professionals. They are LlSl quite rugged and resistant to hand noise (see p. 196) and they requir batteries or special power supply. Many inexpensive microphones come with home recorders are dynamic mikes. Condenser microphones are used extensively for motion picture sc recording. They are often more fragile and more expensive than dynz mikes. Condenser mikes use a capacitor circuit to generate electr from sound, and they must have power supplied to them to function. ‘ may come from batteries in the microphone case, on the mike cable ( the tape recorder itself. Eiectret condenser microphones employ a manently charged electret capacitor. They can be made very cheaply often require no power supply. Sony‘s ECM series of electret conde lapel mikes are used widely. They do require batteries for the prean Flo. 7-6. Electro-Voice 635A omnidirectional dynamic microphone. (Ele Voice) 192 ' [HE HLMMAKEHB HANUBUUK her, but the mike is about the size of a large peanut and is extremely versatile. Ribbon or velocity microphones were once used extensively but they are usually large and few manufacturers still make them. They are some- times used in sound studio applications for their even response to all frequencies of sound. Directionality Every mike has a particular pickup pattern, that is, the configuration of directions in space in which it is sensitive to sound. Omnidirectional microphones respond equally to sounds coming from any direction. Car- diod mikes are most sensitive to sounds coming from the front, less sensitive to sounds coming from the side and least sensitive to those coming from behind. The name derives from the pickup pattern, which is heart-shaped when viewed from above. Hyper-cardioid microphones (sometimes called in-iine, short tube shotgun or mini shotgun) are even less sensitive to sounds coming from the side and behind. Super-cordioid microphones (or super in-iine, long lube shotgun or shotgun) are ex— tremely insensitive to any sounds not coming from directly ahead. How— ever, some hyper- and super-cardioid mikes are manufactured with a certain amount of sensitivity to sound emanating from directly behind as well. Bi-directionoi mikes have a figure-eight pickup pattern with equal sensitivity directly ahead and behind; these mikes are often used in the studio placed between two people talking to each other. Since the names for these microphone types are not entirely standardized among manufac- Super-cardioid Omnidirectional Cardioid FIG. 7-7. Representations of the directional sensitivity of omnidirectional, car- dioid. and super-cardioid microphones (not drawn to the same scale). These suggest the general pattern of the mikes’ response to sound coming from different directions. Imagine the omni mike as being at the center of a spherical area of sensitivity; the diaphragm of the cardioid mike is at about the position of the stem in a pattern that is roughly tomato-shaped. Though the lobes of sensitivity are pictured with a definite border, in fact, sensitivity diminishes gradually with distance. IFIB DOUI'IG HBCOTOBF aflC]. lVllCFUfJflOfle Omnidirectional Head Powering Module Cardioid Head Battery Head FIG. 7-8. Sennheiser K3-U modular condenser microphone system. (Set Electronic Corp.) turers (one company‘s “hyper-cardioid“ is another‘s “super-can be careful when you purchase a microphone. Manufacturers print polar diagrams—graphs that indicate where a microphone is sensitive and in which directions it favors frequencies. It is extremely important to know the pickup pattern mike you are using. For example, many people are unaware of l lobe of sensitivity in some hyperw and super-cardioid mikes, which in unnecessarily noisy recordings (see Fig. 7-9). Hyper— and super-cardioid microphones achieve their direction means of an interference tube. The tube works by making SOUI‘K coming from the sides or back of the mike strike the front and the diaphragm simultaneously so that they cancel themselves general, the longer the tube is, the more directional the mike will proper operation, it is important not to cover the holes in the to your hand or tape. Usually, the more directional a microphone more sensitive it will be to wind noise (see p. 196). Contrary to popular belief, hyper— and super—cardioid micrr 194 - THE FILMMAKER‘S HANDBOOK Back (180°) Cardioid Super-Cardioid FIG. 7~9. Polar diagrams indicating the sensitivity of omnidirectional.lcard101d, and super-cardioid microphones. Imagine each diagram as a cross, section of the mike‘s sensitivity. with the microphone lying along the vertical axts (as the 0mm mike is here). The microphone‘s diaphragm would be positioned at the center of the graph. usually are not more sensitive to sounds coming from directly‘ah‘ead than are cardioid mikes. Unlike zoom lenses, they do not “magnify sound. However, directional mikes do exclude more of the competing back— ground sound, so that they can produce a good recording at a‘greater distance from the sound source—~as recordists say. the “working dis- tance” is greater. The disadvantage of highly directional mikes Is that a filmmaker often encounters situations where it is difficult to capture im- 7 portant sounds within the narrow lobe of sensitivity. A classic case is found in recording a two-person conversation With a super—cardioid microphone: when the mike is pointed at one person, who is then on- axis, the other person will be off-axis, his voice sounding muffled and The Sound Recorder and Microphone distant. Panning a long microphone back and forth is an imperfe tion if the conversation is unpredictable. In such cases. it may b to move far enough away so that both speakers are approxima axis. Unfortunately, the best recordings are made when the micr is close to the sound source. Microphone Sound Quality Microphones vary in their frequency response. Some mikes em the bass or low frequencies, others the treble or high frequencies. The frequency response of a micrOphone or tape recorder is sh a frequency response graph that indicates which frequencies are by the equipment. Favored frequencies are those that are repi louder than others. An “ideal” frequency response curve is flat, ing that all frequencies are treated equally. Most mikes emphasi; frequency sounds more than mid~range or bass frequencies. Filn often choose mikes that favor mid to high frequencies to add cla presence (the sensation of being close to the sound source) to Some people prefer the sound coloration of mikes that emphasiz 1 0 5 IIIIIlll-IIIIIIII-IIIIIIII- IIIIIIIEIIIIIIII-Illlllll! + n+ LEVEL ((18 I CH ‘ I‘ -i - E - - = .=... I E _ E 100 400 1K 2K 5K 10K 20K FREQUENCY (Hz) .--. + 5 ----I a I!splintpylllllli-gaiumn _ Innuranium-Innin- “j lIllltllflIIIIIIll-Illlllll- _15 flflfilllllMllIlll-III 20 50 100 400 1K 2K 5 FREQUENCY (Hz) IIIll- K 10K 20K FIG. 7-10. (i) The relatively flat frequency response of a quality tape i Where the graph deviates from the 0 dB line indicates diminished respons the line). (ii) A microphone frequency response curve. This mike is more to high frequencies. The three parts of the curve at left represent in amounts of bass roll-off actuated by a built-in, three-position switch (: Filters, Chapter 8). 196 - THE FILMMAKER'S HANDBOOK frequencies. A male vocalist, for example, might want to bring out the deep bass in his voice to produce a fuller sound. When you purchase a mike, check the frequency response graph pub- lished by the manufacturer. An extremely uneven or limited response (high frequencies should not drop off significantly before about 10,000 Hz or more) is_some cause for concern. The microphones that come with recorders and cameras are very often of low quality and should be re placed. Set up an AiB test where you can switch from one mike to another and record sound from both mikes. You may find that you prefer the sound of the less expensive of two mikes. An A/B test is especially important if you need two matched microphones for multiple microphone recording (see Chapter 8). Wind Screens and Microphone Mounts The recorded sound of wind blowing across the mike does not in the least resemble the rustle of wind through trees or the moan of wind blowing by a house. What you would hear instead are pops, rumble and crackle. When recording, do not let wind strike a microphone (particu- larly highly directional mikes) without a wind screen. A wind screen blocks air from moving across a mike. ' A minimal wind screen is a hollowed-out ball or tube of acoustifoam— a foam rubber-like material that does not muffie sound. This kind of wind screen is least obtrusive and is used indoors and sometimes in light winds outside. Its main use is to block the wind produced when the mike is in motion and to minimize the popping sound caused by someone‘s breath- ing into the mike when speaking. For breezier conditions, a more substantial wind screen called a zep- pelin is used. Like its namesake, this wind screen is large and tubular; the mike is completely encased in it. In strong winds. an additional sock- like covering can be fitted around the zeppelin. Zeppelins are expensive to buy, but you can make one with mesh and foam. A good wind screen should have no noticeable effect on the sound quality in still air. When you are caught outside without an adequate wind screen, you can often use your body, the flap of your coat or a building to shelter the mike from the wind. Often, a bass roll-off filter helps minimize the rumble of wind noise (see Chapter 8). Besides wind noise, microphones are extremely sensitive to the sound of any moving object, such as hands, clothing, etc., that touches the microphone case. Hand noise, or case noise, becomes highly amplified and can easily ruin a recording with its rumny sound. The recordist should grip the microphone firmly and motionlessly, grasping the looped microphone cable in the same hand to prevent any movement of the cable where it plugs into the mike. The alternative is to use a pistol grip that The Sound Recorder and Microphone FIG. 7-] 1. A zeppelin wind screen for a shotgun mike shown with pistol i mounted on a microphone boom. has a shock mounting to isolate the mike from any hand nOiSt makes the mike slightly bulkier, however. A shock mount can i attached to the end of a fishpole (collapsible) boom, which enab recordist to stand away from the action. Studio microphone boo mounted on a pedestal to relieve the recordist of considerable from holding the boom for long periods of time. Wireless, Lavaiier and Lapel Microphones To allow the camera and subject greater freedom of movement, less, or radio, microphone can be used. With this system, a small clipped on the subject, along with a concealed radio transmitter about the size of a pack of cigarettes. A receiver mounted on the I't picks up the signal with a short antenna. This system opens up many possibilities for both fiction and dot tary filmmaking. Camera angles need never be compromised by erations of microphone placement since the mike is always close subject but out of view. In unscripted documentaries, there ar advantages to letting the subject move independently, without bei' stantly followed by a recordist wielding a long microphone. Ho although a radio mike frees both subject and crew, the use of such 198 - THE FILMMAKER'S HANDBOOK FIG. 7-12. Micron wireless microphone. Transmitter {at left], shown with lapel mike, is smaller than a cigarette pack. An additional short wire is needed as an antenna. Receiver is at right. (Micron Audio Products) makes some people uncomfortable in knowing that whatever they say, even when it is said in another room, can be heard. Some filmmakers object to the way radio mikes affect sound perspective: unlike typical sound recording, when the subject turns or walks away from the camera wearing a wireless, the sound does not change. Wireless transmission is not completely reliable. Depending on the physical obstructions and c0mpeting radio transmissions in the area, wireless signals may carry up to several hundred feet or they may be blocked altogether. Newer, “diversity” radio mikes that employ two or more antenna systems or radio frequencies make the system more de- pendable. Wireless sound quality is usually not as high as that of hard- wired mikes, but some of the systems are extremely good. On some productions, a radio mike is rented by the day for particular recording situations. Lavaiier microphones are small mikes designed to be hung on a cord around the subject’s neck. Lapel mikes, sometimes also called lavaliers, are usually even smaller and are generally intended to be clipped on the subject’s clothing. Either mike may be used with a wireless transmitter or may be hard wired to the recorder with a cable running along the floor. These mikes are usually omnidirectional, although a hyper-cardiod'lapel The Sound Recorder and Microphone - mike has been developed. Because they are so close to the subject tend to minimize other sounds in the environment. Lavaliers are designed to de-emphasize the low frequencies that nate from the chest cavity and to accentuate high frequencies th. lacking. in part, because the mike is so far out of line with the sut mouth. One lavalier made by AKG has a movable collar that can rt a normal, flat frequency response for general recording. Most in lapel mikes are made with a fairly flat frequency response. Most anchorperSOns on television news wear lapel mikes clipr their clothing. For film work, mikes are often concealed beneath a weight piece of clothing. If you do this, listen closely for case caused by the cloth rubbing on the mike. Some lapel mikes are rela insensitive to case noise. FIG. 7-13. Sennheiser MKE 2 miniature electret lavalier microphone Shm necktie. A dark microphone is often easier to conceal on a subject's cl (Sennheiser Electronic Corp.) Connections Between Microphone and Recorder Not all microphones and recorders are compatible; many need \ adaptors or devices between them. Impedance is a measure of the resistance of any audio device flow of electric current. Impedance, sometimes represented by Z, i sured in ohms. The impedance of a microphone may be low or hi; same is true for the microphone input on the tape recorder. In gs 200 - THE FILMMAKER'S HANDBOOK low impedance is 600 ohms or less, and high-impedance devices measure in the thousands of ohms. lt is extremely important to use a low-imped- ance mike with a low-impedance mike input, or a high with a high. Exact matching is not necessary. Usually, microphones with XLR connectors have low impedance. The manuals for the recorder and microphone should list their impedances. In general, it is an advantage to have low-impedance equipment be- cause it allows you to use up to several hundred feet of microphone cable —which is very useful when you cannot work near the sound source— without picking up hum and interference from AC wall current and radio stations. With high-Z (impedance) equipment. 20’ may be the maximum. If your mike and recorder impedances are mismatched, it is necessary to put a matching transformer on the microphone cable. Try to put it closest to the piece of equipment with the higher impedance. Picking up hum and interference from nearby power lines, automobile engines, fluorescent lights and radio stations can be a problem even with low-impedance equipment. The best solution is to use a microphone and recorder that are connected by a balanced cable. In a balanced micro- phone cable, the two wires of a standard cable are enclosed in a sheath- like third wire that insulates them from electric interference (see Fig. 7- 14). Balanced cables can usually be recognized by the three contacts, instead of two, in the connectors at either end. Not all microphones or recorders will accept balanced cables. Whenever you get electric inter- ference, try moving the recorder or the cable to another position. Some, times wrapping the microphone cable, especially the connectors, or even the recorder, in aluminum foil helps. The electric power needed to run a condenser micrOphone may come from a battery in the mike or on the cable, or from the recorder‘s batteries (the latter is called phantom powering). Phantom power frees you from carrying an extra set of usually expensive batteries for the mike. The disadvantage is that, on some recorders, if the microphone input is set up for phantom powering, it will not accept dynamic mikes or condensers that have their own power. Other recorders have a switch that permits input from any type of microphone. Phantom powering often involves rewiring microphone cables to reverse or “flip” the phase, making them not interchangeable with normally wired cables. Most recorders have a line input for connecting the output from a phonograph amplifier or from another recorder. The line input is designed to accommodate the strong, usually high-impedance signal these ma- chines generate. Sometimes when you connect two pieces of equipment, a low (60 Hz) humming sound results if either piece is plugged into the AC wall current. If this happens, connect a ground wire between the case of one machine and the case of the other. Most phonograph turntables have such a wire connecting them to their amplifiers. The Sound Recorder and Microphone J“ Signal 2 [Ground Signal 1 Insulator \ 63 Bands Ground Insulator Signal FIG. 7-14. Audio connectors. (i) W males and female. A three-contain plug is at left, a two-contact mono plug is in the center. The three-contac can also be used for balanced cables. (ii) RCA or phono male and fen Mini-phone or simply mini male and female. This is a miniaturized versi Mi" connector (diameter is 1/3" instead of 1/4"). Sony makes a stereo versit plug, recognizable by the two black insulator bands (see i). (iv) Three-pi male and female. The sleeve on the female engages the threads on the m Tuchel is a variant ofa DIN connector. (v) Three-pin Cannon or XLR cor The male and female snap together. Both XLR and Tuchel connectors r more than three pins. The female XLR is pictured with the insulation . to show the balanced or stereo cable with the two signal wires CHCaSt sheath-like ground. (vi) Banana plugs and jacks. 202 - THE FlLMMAKEFl'S HANDBOOK It is worth remembering the names of connectors used for microphone cables as they can be extremely difficult to describe. All connectors have male and female forms; the male is sometimes called the plug, the female, the jack. Sound Systems As discussed in Chapter I, synchronous motion picture sound is usu— ally recorded either directly in the camera on magnetically striped film or with a separate recorder specially equipped for film work. These tech- niques are known as single and double system, respectively; the names refer to the number of strands of material needed to reproduce sound and image. Single System The chief advantage of single system is its simplicity. One person can easily carry and operate the camera with the microphone attached, and, with automatic level control, the filmmaker is free to concentrate on the shooting. 1f little editing is to be done, this is an extremely convenient way to work. Single system recording is now used far more extensively in super 8 than in the 16mm format. In super 8, the sound quality is good but is inferior to that of a good V4" tape recorder or even some cassette re- corders. When the camera is operated at sound speed (24 fps), the sound quality is better than when it is run at the slower silent speed (18 fps). Most single system cameras have automatic gain control; some have manual override and a VU meter for setting the level (on some cameras the meter can be read through the viewfinder for adjustments while shoot- ing). Most cameras accept an ear plug, which allows you to monitor the sound as it goes to the record head. A few 16mm cameras have separate playback heads for monitoring the magnetic stripe. Although many single system cameras accept detachable mikes, and sometimes separate volume controls, that can be operated by someone other than the camera person, a good deal of single system filming in- volves microphones that are mounted on the camera or held by the cam- era operator. The mike is thus too far from the sound source and too close to the noisy camera. Many cameras have an extendible microphone boom, which helps somewhat (see Fig. 1—7). The camera should generally be positioned so that the mike stays close to the SOund source. Very noisy cameras should be fitted with a sound-dampening barney. Camera-mounted microphones usually have an omnidirectional or car- dioid pick-up pattern so that they are sensitive to sounds coming from The Sound Recorder and Microphone - FIG. 7-15. Cinema Products CP—lélA camera outfitted for single system re: ing. The amplifier and level controls for the sound system attach as a unit It camera’s right side; the magnetic sound head is plugged into a receptacle ll film path. As these cameras were once the standard of the news industry. CP—16/A cameras can often be purchased cheaply now that they have been la‘ replaced by video equipment. directions other than the one in which the camera is pointing. Far bl recordings can be made by handholding a more directional mike Chapter 8, Filming Alone). If you are making a film that you plan to edit in single system, I are advantages to shooting film stock that has been presrriped by manufacturer (rather than poststriping during editing) even if you pl; record the sound after the footage has been edited (see Chapter 12, l‘ netic and Optical Tracks). Double System Virtually all professional filmmaking is done with double system et ment. Although double system seems complicated and somewhat t bersome, the quality and flexibility of the equipment far outweigh drawbacks. With double system, a sound recordist can properly mor and control the recording level, can use multiple microphones and, s the camera and microphone need not be connected via cable, can t microphones optimally for recording. 216 - THE FILMMAKER'S HANDBOOK in place quickly. Traditional clapper boards are sometimes held upside down to indicate a tail slate (see below). Another slating device is the slate light. which is connected to the recorder. When its trigger is pushed, it flashes a small light (some flash consecutive numbers to identify takes) and it produces an audible beep. The slate light can be very handy for documentary filming, although the light is sometimes hard to see in daylight. Cameras using cable sync systems. or a special radio slate transmitter, sometimes employ bloop lights, which flash a few frames of film inside the camera while sending a beep tone to the recorder. Crystal sync rigs sometimes use time coding. With this technique, appropriately equipped cameras print out a code every second or so on the edge of the film. With some systems this code must be read by machine, while others, like the Aaton system. print legible numbers. Other systems magnetically record the code on film stocks prepared with an invisible magnetic coating in the base. A gener- ator in the recorder puts a similar code on the tape which is ultimately printed or recorded on the magnetic film. The great advantage of these systems is that they allow automatic silent slating of any number of cameras and recorders, identifying every foot of film by the date and time of shooting and, with a properly equipped editing table, providing auto- matic synchronization of the workprint and magnetic film. Slating can also be done by gently tapping the microphone once or twice or even by snapping your fingers within range of the recorder. When you make any slate. it is imperative not to turn off the camera or recorder between the slate and the shot itself . as novices sometimes do. Make sure that the slate is really visible and clear to the camera to avoid spending unnecessary time synchronizing the rushes. it's a good idea to say “slate” into the mike after a slate made by finger snapping or mike tapping to aid in finding the sound later. When possible. head slates, which are done at the beginning of the shot, are used. Head slates speed the process of putting the sound and picture in sync in the editing room. Tail slates, done at the end of the shot. are often preferable for unstaged documentary filming since they are less disruptive and do not announce to the subjects that filming is about to begin. If the film runs out before the last tail slate on a roll and the camera operator says “run out,” you can use this as an approximate slate. In any situation, a gentle, quiet slate helps put actors or film sub- jects at ease. Generally, actors should not be rushed to begin the action immediately after the slate. It is more difficult, but certainly not impossible, to put shots in sync without a slate (see Chapter 12). The term slate also refers to the recording of information on film or tape. MOS takes are slated. not for synchronization, but to identify the scene number on film at the head of the take ("MOS" should be written Sound Recording on clapper board and the hinged bar should not be raised). Eac film is normally slated at the head by shooting the camera roll and date on a card or clapper board so the number will be visible Similarly, sound tapes are slated at the head with information or number or the centent. Recording Technique Basic Strategy The general objective in scund recording is W closeenogg‘hio the sound sourc duce a loud and clear sour A good track should be easily intelligible, should lack strongly/73b background sounds, unpleasant echo or distortion and should be ably faithful to the tone quality of the original sound. Once a g00t mg is in hand, you have a great deal of freedom to alter the chai the sound later as you choose. The ideal placement for many mikes is between 1 and 3 feet in the person speaking, slightly above or below the level of the n the microphone is directly in line with the mouth it may pick up sounds from the person breathing into it (see Chapter 7). If a dii mike is too close, it will bring out an unnatural bass tone quality the proximity effect; which results from the particular way low. eies interact with directional microphones. If a microphone is from the subject, background, or ambient, somid often drowm speaker’s voice. Also, the undesirable acoustic qualities of the r 7 space, like echo and boominess, become more noticeable (see b: The microphone‘s position is almost always compromised by era’s needs._lt is important, however, that the sound source b it within the pickup pattern of the microphone. Keep in mind the like light, diminishes in intensity with the square of the distance 9-4). Thus, moving twice as far from the sound source dimini sound to one quarter of its previous level. If the recording lev sound seems low. especially with respect to louder background ; you must get closer to the sound source and not try to correct the by turning the level way up. Many beginners think the recordist should try to capture all :~ .1 a general fashion, standing back from, say, a party, a conversa street scene to record all the sounds together. The result of sucl tugs is usually an indistinct blur. The recordist should instei individual sounds and get close enough to record them clear overall mélange of sounds is desired, it may be necessary to mix 218 - THE FILMMAKEFI‘S HANDBOOK several distinct tracks later. For documentary filming in noisy conditions, it is often necessary for the recordist to get closer to the subject than he may feel comfortable doing. If this should happen, the camera person must insist that the mike be brought closer; a sense of professional de- tachment helps to overcome shyness. Putting the mike very close to the sound source minimizes both am- bient sound and the natural echo or reverberation of sound reflections in the recording space. In some situations, a close mike sounds artificial. For example, if the camera is filming a distant long shot and the mike is very close, the recording will lack the proper soimd perspective. Al- though distorted sound perspective is found regularly in films, some peo- ple object to it. To correct this, the recordist could move farther back, but at the risk of sacrificing clarity. Alternately, after the sound has been recorded, a reverb unit can be easily used to give a sense of distance to the sound. Similarly. any missing ambient sounds can be easily added later by mixing in a second track. These kinds of effects are often better handled under the controlled conditions of sound editing than they are while making a live recording. You can always add background sounds, distance effects and equalization during sound editing and mixing, but nothing can make a noisy, echoing or weak recording sound pleasing and clear. Ambient Sound Ambient sounds are the background sounds that surround any record- ing space. They can come from birds, traffic, waves, refrigerators, flu- orescent lights, stereos and the like. The best way to minimize their effect, when possible, is to eliminate them entirely. Don’t shoot the birds, but do unplug refrigerators, turn off air-conditioners and close windows facing out to the street. For fiction filming, locations should be planned with ambient noise in mind. Try not to set up shooting in an airport flight path or by a busy highway. Sometimes you can get permits to block off a street temporarily while you are shooting; otherwise, plan to shoot at a quiet time of day. Audible ambient sounds should ideally remain consistent throughout a scene. Consistency is important for editing since much condensing and rearranging of the film’s chronology are done at that time. An editor needs the freedom to juxtapose any two shots without worrying if the background tone will match. The audience will tune out the gentle ambi- ence of an electrical fan, but may notice if it pops in and out in every other shot. If you begin shooting a scene with the window closed, do not open it during the scene. in situations where you can not control some background sound (a neighbor‘s auto, for example), record some of the offending sound alone in case during editing you need to cover sections Sound Recording of the scene that lack it. In some cases, an inconsistency in th» ground sound will seem logical and need not be disguised. Make every effort to turn off or lower any music that is audibln filming location. Discontinuous music is a glaring sign that the chrt of shots has been changed. Recording copyrighted music may alsr legal problems. If ambient music cannot be eliminated, or if it is the scene you are filming, plan your editing around it when you 51' You should always record about a minute of ambient sound a location.- Even if nothing in particular is audible at the location Site has its distinct room tone, which is quite different from the St dead tape that has nothing recorded on it. Room tOne-——an ex that refers to outdoor sound as wellmis used in editing to brid ep the sound track, providing a consistent background. g Recording in Noisy Locations If strong ambient sound is overpowering the sound you want to there are a number of ways to resolve this. First, try to get the phone. as c10se to the source as possible. Using a microphont sometimes helps; you can often get closest by miking from the bottom of the frame rather than from the sides. ‘Lapel or lavalier mikes are often useful for close recording Th espeCially effective for a single subject or for situations where t‘ sons are near each other. These mikes can usuain be concealed subject. They can also be hidden, for example, in a piece of fu Placmg a lapel mike in the center of a small table is sometimes 1 way to mike unpredictable dinner table conversation. (The mike not be placed directly on the table surface or it will pick up the vi of objects being put down onto the table.) When they are used Wireless transmitter, lapel mikes can provide good-quality sr scenes With lots of subject movement and long shots where h' mikes would be impractical. ‘ Often the best solution to block out loud ambient sounds is 1 32m directional microphone and use its pickup pattern to its best e. I When youare using any microphone, never let the subject cc _~_~ tween the mike and a major noise source, like the street Stant street to mike someone on the sidewalk; do not stand with your the buddings where you will pick up the sound of your subject street .HOISe equally. With a super-cardioid microphone if you C’l the mike upward from below (or down from above) you can in street level background noise, including sound reflected off buildi: As camera neise is a constant problem on sound tracks. alway 220 - THE FILMMAKER‘S HANDBOOK pointing the microphone in the direction of the camera or its reflected sound (see Fig. 8-5). Acoustics of the Recording Space The size, shape and nature of any filming. location affects the way sound travels through it. An empty room WI.th hard, smooth walls 15 acoustically live, reflecting sound and causmg some echomg. Bathroom:j are usually acoustically live“, sound may reverberate 1n.them fora secoln or more before dying out. A room with carpets, furniture'and irregu ar walls is acoustically dead; sound is absorbed or dispersed irregularly by the surfaces. Wide-open outdoor areas are often extremely dead, becatlise they lack surfaces to reflect the sound. Listening to the way ahand c ap or whistle dies out is a good way to test the liveness of a recording space. The acoustics of a location affect the clarity of the sound track and the loudness of camera noise. It is hard to hear clearly in an overly live room (a boamy location) since high frequencies are lost-and rumbly low fre— quencies predominate. If you have tried. to talkan a tunnel, you are familiar with what it does to the intelligibility of veices. _ There are a number of ways to improve an overly reverberant location. You can use a directional mike and move closer to the sound source. A room can be deadened by closing curtains or by hanging blankets on the walls and spreading them on the floor (many recordists carry sound blank; kers for this purpose). Avoid positioning a microphone near a smoot wall where it will pick up both direct and reflected sound, Since echo may FIG. 8-5. Microphone positioning. (A) An improperly positioned directional mic; crophone is pointed directly at reflected camera nOise. (B) Microphone p-oiSitiorit;1 to reduce response to both direct and reflected camera notse. (For clarity in _e illustration. the microphones are shown further away from the subject than is optimal.) Sound Recording be increased or sound waves may cancel each other, weakening crophone‘s response. This may also occur when mikes are mount short table stand over a smooth, hard surface. Avoid placing the a corner or equidistant from two or more walls where reflected may cancel or echo. Sometimes boominess can be reduced by 1 out low frequency sounds below about 150 Hz (see below). If a space is too live, even a quiet camera‘s noise will souni When you point the mike away from the camera, you often are ai: reflected sound bouncing offa wall. When this happens, deaden thu with blankets, move closer to the subject or use the pickup patteri mike to cancel out both direct and reflected camera noise. Bass Filters Many recorders and microphones are equipped with filters that the level of low-frequency sounds. These filters are variously call: cut, bass rail-off, high pass and low-frequency attenuation. SOITlt cut off bass relatively sharply at some frequency, say 100 Hz. 0th off low frequencies more gradually, often diminishing them 12 - octave; thus the filter might reduce 150 Hz somewhat, 75 Hz qui' and 37 Hz almost entirely. Microphones and recorders often have a two- or three-positic roll-off switch. The first position (sometimes labeled music or i\ vides a relatively flat frequency response with no bass filtering. Ti position (voice or V) provides filtering below a certain frequency. 1 is a third position, it rolls off bass starting at an even higher frei (see Fig. 7-10). It is extremely important to do test recordings vi filter to judge its effect. On some mikes, the “M” position is optii most recording, and the “V” position should be used only for em rumble or wind noise or when the mike is very close to someone ing. Sometimes, the third position removes so much of the low e: recordings sound very thin and hollow. Filtering, also called equalization, is done to the low frequen minimize the rumble caused by such things as traffic or machine wind or handling noise on the microphone. The lOW-frequency t nent of these sounds is disturbing to the listener and can cause modulation interference, which distorts higher-frequency sou1 low-frequency sounds are loud, the recording level must be kept avoid overrecording, and this diminishes the quality of the souni are more important (such as speech). There are two schools of thought on filtering bass: one is ti liberally in the original recording, the other is to hold off as in possible until the transfer to mag film or until the production of ti 7 magnetic or optical track. The first school argues that the low freqii will be filtered out eventually, and a better recording can be made “mwunmmmmw- ,,,....—..... .v. .A 222 - THE FILMMAKER‘S HANDBOOK is done sooner rather than later. Although this is true, the problem is that frequencies that are rolled off in the original recording may not be re- placeable later. The sound studio is a much better environment in which to judge how much bass needs to be removed. ‘ A more prudent approach is to filter bass only when excessive rumble requires it or when trying to compensate for a microphone that IS overly sensitive to low frequencies, to wind or to handling noise. Then, filter only slightly—perhaps at the second position on a three-position roll-off switch. During the transfer to mag film or in the sound mix, a quality equalizer can be used to remove what is unnecessary (see Chapter 12). if bass filtering is done, it should be kept consistent throughout a scene. Multiple Microphones There are many situations in which it is preferable to use more than one microphone. Typical examples ofthis are when recording two people who are not near each other, recording a musical group or recording a panel discussion. Many recorders have provisions for two microphone inputs, and some machines can record from microphone and line inputs simultaneously. Mikes can usually be fed into the line input with the proper preamplifier or matching transformer on the cable. Portable mi- crophone mixers, which can be rented cheaply, allow several mikes to be fed into the recorder. Try to get microphones that are well matched in \MWA 4 _ i ll 1/ . Working : l [X : Distance : i x’ : . g / ‘ u I A B A 3x working distance [3 ii} (iii FIG. 8-6. Multiple microphones. (i) Distance from woman to microphone A is only slightly longer than distance to microphone B, leading to possrble. phase cancellation. (ii) Separation between microphones is three times the distance from each mike to its sound source. Now the distance between microphone A and the woman at right is sufficient to minimize the chance of phase cancellation. Sound Recording - terms of tone quality. Sometimes a filter can be used on one mike to it sound more like another. The main problem with recording with more than one microph: the risk of diminishing the strength and quality of the sound signal. peak of a sound wave reaches one mike slightly before or after it re. another mike, phase cancellation results. In phase cancellation, tht phragm of one mike is pushed by the sound pressure while the mike’s is being pulled and the two signals cancel each other out. Thi of thumb for avoiding phase cancellation is that the microphones S: be at least three times farther from each other than the distance each mike to its sound source. Directional microphones that are a away from each other can often be placed closer together. Whenever you use multiple microphones, carefully check that strength of the sound signal is increased, and not decreased, by a mikes. Watch the level on a VU meter when you plug the second in. Sometimes two microphones are wired differently, so that even mikes are placed correctly, they cancel each other anyway. Als avoid unwanted noise, try to keep the level down on the mikes c0\ people who are not speaking; this is often difficult when recording u dictable dialogue. If the recorder can record more than one track at a time, severa sibilities are opened up by using multiple microphones. With a s recorder, you can place two mikes in different positions and cl whichever sounds best later. If different subjects have their own i and recording channels, their lines of dialogue can be separated for ing and mixing purposes. Director Robert Altman developed a Si} track recording system fed by wireless microphones on individual a with each transmitter on a different frequency. With this systen : ' actors can freely improvise, and everyone’s lines will be recorded something that is difficult or impossible to do with only one mike. u cancellation can be avoided with multiple recording tracks since th 3' tor can choose the sound from one microphone or another without ' to mix them together. The stereo Nagra has three recording track third channel is available for slating and recording information. Wit] you can shoot with several cameras simultaneously and not disru recording for slates—a real boon for filming musical performance.- same is true of equipment that employs time coding. Recording Music Below are listed some suggestions for recording a musical sound ‘ ,t 1. When you record an individual instrument, place the mikt the point where the sound is emanating (for example, the hole of a guitar or the finger holes and bell of a saxophone). . 224 - THE FILMMAKER’S HANDBOOK 2. When you record a number of instruments with one microphone, experiment with various mike placements to find the one that balances the instruments nicely. The mike should usually be somewhat above the level of the instruments, closer to the quiet ones than to the loud ones. One well placed omnidirectional mike can often achieve good results. Sometimes a second mike is added to capture a vocalist or soloist. 3. When you use more than one mike, be careful to avoid phase cancellation. 4. When you record amplified vocalists or instrumentalists, it is usu- ally necessary to place the mike in front of the loudspeaker, not the person. When you record a speaker at a podium, you will probably get better sound by miking the person directly. but you must get the mike very close. Often with amplified speeches or music you can get a line feed directly from the public address system (or a band’s mixing board) to your recorder. By doing this, you avoid using a microphone and you usually get good— quality sound (in the case of the band’s mixer, you get premixed sound from multiple microphones). 5. When you record music from records. do not use a microphone. Instead, connect the line output of the phonograph’s amplifier to the line input of your recorder. 6. When you record a musical performance. avoid using the auto— matic level control or adjusting the recording level a great deal during the performance. Ideally, the musicians should control the level of the sound. Sitting in on a rehearsal or following the score is a good way to prepare yourself for sections that will need level adjustment. Also, slow tape speeds may require keeping the re- cording level slightly lower than normal (see Chapter 7). 7. When you film a musical event, be sure to shoot a number of cutaways that can be used to bridge various shots or tie together two takes from different performances. Performance sound must be relatively continuous, and you will need film footage to cover much of it (unlike, say. a lecture which can be easily excerpted). Shooting with more than one camera helps ensure that you will have sufficient coverage. 8. If you plan to use music in your film, you should be familiar with music copyright laws (see Chapter 16). i Recording Sound Effects Sound ejflfects (SFX) are nonmusical, nonspeech sounds from the en- vironment. The sounds of cars, planes, crowds and dripping water are all considered effects. Effects usually have to be recorded individually. Do Sound Recording not expect to get a good recording of effects during scenes that ll dialogue. An effect may be difficult to record well either beca practicalities (positioning yourself near a jet in flight. for exam; because it does not sound the way the audience has come to expen sound _(for example, a recording of a running brook can easily soul a running shower). It is often better to try to simulate an effect (cri cellophane to produce “fire” sounds, for instance) or to purcha.K recorded effects from a sound library or mix studio (see Chapter I: Filming Alone Filmmakng is sometimes called the collaborative art, because mally requires the input of large numbers of creative and technicz sonnel. It is possible, however, for a filmmaker to shoot sync-soun: With a very small crew or even alone. A small crew or solo filrnn opens up possibilities for making movies on extremely low budget allows the filmmaker personal creative control over his work sim that of a painter or writer. In documentary work, a crew of on permit filming subject matter that would be inaccessible to a larger Much of the “personal” documentary cinema that began in the late only became feasible with the development of portable, lightweight recording equipment. The filmmaker working alone may decide to record sound in a system camera or with a lightweight double system recorder, li Nagra SN or a small cassette recorder. Larger recorders can be ust they are often unwieldy. Some people use camera-mounted micror to keep both hands free for Operating the camera and the recorde disadvantage of this method is that the microphone is always poll the same direction as the camera. Better sound can usually be rei by handholding a directional microphone, which makes operati camera and lens controls more difficult, but not impossible. A fe\ makers shoot this way regularly, using wide-angle lenses (10mm 0n cameras or about 6mm in super 8) that have great depth of fie requ1re little focus adjustment. With cameras that do not rest - shoulder, it makes sense to use a shoulder or body brace to stea _camera and relieve some of the weight from the right hand. As long as the microphone is attached to the camera, it is nec ' or the filmmaker to stay relatively close to the subject to recon 7.: sound. More fiexrbility can be had by mounting the microphone ubject. This can be done with a wireless transmitter that feeds a rt on the recorder or the camera. For example, Cinema Products in wireless receiver that mounts neatly on their single system 16mm c: Altemately, a small recorder can be placed on the subject (in pocket, for example) and operated either by the filmmaker, by the s 226 - THE FILMMAKER'S HANDBOOK or by remote control from the camera. Slates can be done by snapping your fingers in front of the lens within range of the microphone. For all single-person filming. it is helpful to have some form of auto- matic control for the recording level. Technique for Single System Filming 7" One of the’biggest drawbacks of working in single system is the 18 or 26-frame separation between sound and picture that can make editing so difficult (see Chapter 12, Single System). Unless you plan to transfer your single system footage to video or to double system, it makes sense to tailor your shooting style to the limitations of the medium. Plan your shots so that they go together with as little editing as possible. Shoot longer takes than you might otherwise, and do not divide a scene into many separate shots or angles. If you begin and end each shot when no one is speaking (or at least when nothing crucial is being said), when you splice shots together you wil! not lose important sections of the sound track. Of course, if there are scenes for which you will not use the synchronous sound, you can take more liberties with short shots and quick cuts. L. My, a. ..... min: ...
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Mikes - The Sound Recorder and Microphone The MicrOphone l...

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