Link to article: Col. Hornby's Audio Guide.
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[[>]] [[module Rate]] [[/>]] **You may have come here from:** [!-- [http://scp-wiki.wikidot.com/col-hornby-s-personnel-file Col. Hornby's Personnel File] --] [http://scp-wiki.wikidot.com/tf-alpha-440 Task Force Alpha-440 (aka "What the hell was that sound?")] + Introduction I have been working on audio editing and theatre tech in varying capacities for the past twelve years. In that time, I have acquired a fairly extensive working knowledge of what goes into creating audio dramas. This knowledge was gained through university level courses, paid employment, volunteer work, and what could perhaps best be described as the old apprenticeship system. With the hope of stimulating the creation of SCP Foundation audio dramas, I decided it would be helpful to condense and share that knowledge with the community. > [[span style="color:#880000;"]]This is not an official document, and not intended as a strict guideline for writing SCP Foundation audio dramas. These are instead (hopefully) helpful insights I have gained through years of training and experience working with audio production for music, theatre, SFX, radio, and the like. Additionally, while this guide is intended for those working predominantly on horror fiction and the examples reflect this, much of what is discussed is applicable across genre and format. **You are free to follow or ignore any of these tips!** - //Hornby//[[/span]] [[toc]] ---- + Recording Audio Dramas: The Least You Need to Know [[tabview]] [[tab The Least You Need To Know]] There's a lot to know about recording audio dramas. This section is intended to include the basics - hopefully enough to send you on your way without scaring you off. [[/tab]] [[tab Recording Vocals]] ++ Recording Vocals > “Compared to sound at [a video shoot], the technology for voice-only recording is a piece of cake.” – Jay Rose, //Producing Great Sound for Film & Video// +++* Engineering a Voice Recording You may find yourself being both the director and engineer. Even if you’re just the director, it’s worth knowing the engineering end of things. Engineers often have most experience with music recording; vocal recording is a beast of a different color. ++++* Plan the Session First Preparation for making a good recording starts long before the vocal talent crosses the threshold. # Is the recording space suitable for a voice-over? # Do you have the right kind of equipment? # Do you have the non-technical accessories which will make things go more smoothly? **First, you need to determine if the space is suitable for a voice-over recording.** The best way to do this is to walk around in the room and listen for noise and echoes. It probably goes without saying, but it’s important, so I’ll reiterate it anyway: **noise and echoes are __bad__.** Noise becomes clutter the mixing engineer has to figure out how to hide (definitely the worse option from it not being there in the first place). If noise is hard to remove, echoes are impossible. Most quiet music studios, in fact, have far too much echo for use for vocal recording. So, how do you determine if a room echoes? Make a loud sound which abruptly stops (going “UCK!” like a barking seal works quiet well) and listen to how this reflects back to you off the far wall. Use a vocal sound rather than a hand clap, since the frequencies are different. If you don’t hear much of anything, you’re probably fine. If there is an echo but it is short and matches timbre to your test sound, you may still be okay. Otherwise, find a different location. (Bear in mind that “a different location” may simply be somewhere else in the same room, since room acoustics are not generally the same in all parts of a room.) Last, do everything you can to get rid of background noise. Turn off the florescent lights and refrigerator and remove the CD from your laptop’s drive. That will hopefully stop the worst of it. **Second, gather the equipment you need.** I could go on for pages about the minutia of expensive microphones and recording equipment, but if you’re reading this, I assume you probably have little more than a laptop microphone. That’ll do. If you’re interested in doing recordings on a regular basis, I recommend the [http://www.bluemic.com/yeti/#/desc/ Blue Yeti] microphone, which is what I use. Regardless, you want the microphone as directional as possible. If your microphone has a mechanical switch allowing different envelopes (the areas picked up the most), set it to “cardioid” (so named because it’s the shape of a heart). If you’re using an internal mic in your laptop, go into the sound settings and see if there is a way to set it to as limited a directionality as possible. Not great, but superior to settings intended for conference calls. Next, grab your headphones. Over-ear are better than earbuds because they do a better job of blocking out the background sounds. These will be your ears during the recording process. **Third, gather the non-technical stuff.** These will make the recording go much smoother. * A tall stool for the voice actor. Professionals prefer either standing or leaning, since it does less to constrict the airway. Low chairs don’t help the posture. * A good script stand. Life is easier on the voice actor if they don’t have to hold the script still to keep it from rustling. (Note: print out the script – NEVER just read it off a computer. The “tap” of the arrow keys and “click” of the mouse used to scroll down the page is audible.) * Lights that won’t glare. * Water for the voice actor. Use room temperature water, rather than cold water, because cold water tightens the throat. Anything carbonated is right out! ,,//(Urp.)//,, * A pencil for marking script notes. ++++* The Recording Session As the old saying goes, the more you sweat before the battle, the less you bleed during it. So with recording – the session itself should be simple if you prepped properly. Test your recording equipment. Make sure it records properly. Nothing is worse than doing an hour’s worth of recording and discovering that nothing actually recorded. Before actually recording anything final from the actor, ask them to talk a little bit into the microphone (simply reading random bits of the script is fine). This will allow you to fine tune the placement on the mic, since every actor is a little different. **Place the mic so the actor is talking past it, rather than into it. This will help prevent plosives (“P” “T” “K” and the like) from making popping sounds.** Record 30 seconds or so of “room”. This should seem like recording silence. What you’re doing here is actually recording the little bits of background sound that will be there, giving the mixing engineer something to intercut between dialogue. While you’re recording, you only have a couple of responsibilities: * Keep track of takes and take numbers, write them down on the script, and provide a verbal slate (“take 3”). These are essential so that 1) nothing gets missed during recording, and 2) the mixing engineer can figure out what recordings are where. All of the notes you take should be forwarded with the raw audio to the mixing engineer. * Keep an ear open for problems and be ready to fix them. While the director focuses on the performance from a content angle, you should be focusing on the performance from a technical angle. If the actor’s mouth has dried out and you can hear that through the recording, stop for water. If the mic pops from plosives, reposition it. And so on. Play back a little of the recording after each take to make sure it worked properly. +++* Directing a Voice Recording The script has the following line: > **AGENT:** Holy shit – we need to get out of here right the hell now! Move move move! The job of the director is to make the actor say that like this: > **AGENT:** HOLY SHIT! We need to get out of here! Right! The! Hell! NOW! MOVE! MOVE! MOVE! Or like this: > **AGENT:** ,,Holy shit,, - we need to get out of here! Right the hell now! Move, MOVE MOVE! Same line, two completely different deliveries. The script may not include the subtle details on how a line should be delivered. That’s where the director comes in. __The only way to evaluate a voice is to listen to a recording demo__. I would describe myself as having a tenor/baritone speaking voice with an American accent which has the slightest hints of Northern English (not quite Scottish) lilts. Without a recording demo, you probably wouldn’t be able to cast me. Consider Jason Isaacs and Michael Caine. Though they both have British accents (different British accents, of course) and both have similar vocal ranges, they sound nothing alike. It’s always worth listening to a recording demo even for yourself or people you know personally. This is because some voices translate to recordings differently from how you’d expect. Giving instructions and feedback to voice actors is similar (but not identical to) giving instructions and feedback to stage actors. Remember, the only thing that matters to the final product in a vocal recording is the sound. When you’re talking to the actors, you want to walk the line between giving lots of feedback (actors can’t read minds) and being a motormouth. The important thing is to keep your feedback meaningful. “Excellent, do more like that” isn’t helpful, but “try changing the emphasis from ‘here’ to ‘get out’” is much more likely to translate into what you were hoping for. Keep a record of all the tracks, with notes on what went well (“good energy – use this take”) and what went badly (“emphasis was wrong, avoid this take if necessary”). These notes should be forwarded to the mixing engineer. [[/tab]] [[tab General Recording Tips]] ++ General Recording Tips * Find a quiet place with as little ambient noise as possible (believe it or not, in a closet with lots of clothing works surprisingly well at deadening ambiance) and record as clearly as possible. Post-production fixes are “Band-Aids” and always inferior to clean source audio. For a visual metaphor, imagine taking a photograph which is blurry because the camera was shaking and trying to make it clear – easier said than done, and even a spectacular clean-up job won’t be as good as a nice original image. * “Clipping” cannot be cleaned up in post-production. Leave “head room” – in other words, the loudest sound in your recording should be between -6 and -12 dB. If it hits 0 dB, you’ll clip. * Unplug the refrigerator and turn off any florescent lights. If you’re using your computer to record, make sure the CD drive is empty (so it won’t spin). These give off hums that are easy to tune out when in the room, but they get picked up on recordings. * Unlike cameras, microphones cannot be made to not pick up something in the area. Even very high quality directional microphones will pick up sounds outside their intended area. Also, remember that microphones will pick up sound from behind the intended subject of the recording. Recording with the microphone pointed at someone seated in front of a window is less ideal than someone seated in front of a solid wall. * If possible, placing your microphone a little below and to the side of your mouth is a good idea - it'll help keep plosives (like "P" and "T") from causing cracking in the final product. * If you've got any pronunciation questions, don't hesitate to ask the author or director. While many people won’t prefer pot-ah-to verses pot-ay-to, having two characters talking to each other with varying pronunciations of the same thing can get annoying. This is especially true in the case of proper nouns. * If you screw up, just stop, take a moment, and start again from somewhere identifiable (identifying where you're restarting will make the sound engineer’s life a LOT easier). The easier you make it for me to piece takes together, the happier they'll be. * Lots of smaller sound clips is also better than one massive long one, at least from an editing point of view. * Listen to your recordings when you’ve finished. See if anything sounds out of place. If it’s something making background noise, can you turn it off? If it’s a place you misspoke, rerecord it. Think about what the director or sound engineer might tell you – if you can anticipate their comments and suggestions for improvement and incorporate them, it will cut down on the back-and-forth. * “Volume” in voice acting is often conveyed by tone more than actual volume. A low, slightly hushed tone can convey “quiet”, while a more energetic or agitated tone might convey “loud”, even if the volume is technically the same. Neither actual whispering nor actual yelling records as well as you might think. [[/tab]] [[/tabview]] ---- + Quick Checklists [[tabview]] [[tab Introduction]] +* Introduction to Quick Checklists These checklists are intended for use by anyone involved in the production process. Though simply general guidelines rather than hard and fast rules, checklists can make life a lot simpler by ensuring that things don't get forgotten. After all, absentmindedness happens to the best of us. **Who are you?** Well, statements about personal identification aside, you may have one role or several - we're not Hollywood, so in practice we're unlikely to actually be anywhere near as formal as the below descriptions might suggest. Additionally, while the checklists are intended to be sufficient for their respective users, it never hurts to glance at the other checklists to understand what's going on. > **__Producer__** - The person who manages the production. //He or she ensures that everything that needs to happen does within whatever time frame is set for the project. Simply put, the producer is "the boss," at least from an administrative standpoint.// > **__Scriptwriter__** - The person who writes up the script. //This individual or group of individuals is responsible for creating the story, writing up the dialogue, "stage directions" (though here, unlike in theatre, it is a sound stage rather than a physical one), ensuring that the formatting is useable by everyone, and the like. This is the role most people on the wiki will be most familiar with, as it is the one closest to simply being a text author.// > **__Director__** - The person who is in creative control of the production. //The director casts and directs the voice talent, decides yes or no on sound effects (SFX) and music, and oversees the project from a creative standpoint. (In "the real world" of production, the producer is usually the director's boss, though the director generally gets significant ability to set the direction of the project from an artistic standpoint. For our purposes, it is entirely conceivable that these may be the same individual, but this is not necessarily the case.)// > **__Voice Actor__** - Also known as the "talent", voice actors (the term is conventionally gender neutral) are the people being recorded playing the characters. > **__Recording Engineer__** - The person who handles recording the audio of the voice actor[s] and/or SFX artists. //If you're sitting recording yourself on your laptop's microphone, then you're the recording engineer, in addition to the voice actor.// > **__Mixing Engineer__** - The person who takes all the raw source audio and mixes it together into the final product. //This person is not necessarily the recording engineer, since production and post-production are separate parts of the process. The recording engineer works in production; the mixing engineer works in post. Mixing engineers tend to have to spend many hours putting tracks together - from a technical standpoint, they usually have the most work. __Making their lives easier is a good idea__.// [[/tab]] [[tab Producer Checklist]] +* Producer Checklist > **__Producer__** - The person who manages the production. //He or she ensures that everything that needs to happen does within whatever time frame is set for the project. Simply put, the producer is "the boss," at least from an administrative standpoint.// **Involved in:** Pre-production, Production, Post-production **Skills needed:** Administrative acumen, time ++* **CHECKLIST** +++* Pre-production * Has the story been outlined? * Has a writer been selected? * Has the director been selected? * Has the production crew been selected? * Has permission been received for use of unoriginal content? * Has the script been peer-reviewed? +++* Production * Have the actors been recorded? * Have the SFX been recorded and/or obtained? * Has the music been recorded and/or obtained? (Ensure the rights are cleared.) * Have the recordings been forwarded to the Mixing Engineer? * Has the Mixing Engineer received all the necessary raw parts? +++* Post-production * Is the rough mix (no music) good? * Is the tentative final mix good? * Is the final mix good (content)? * Is the final mix good (technical)? * Has the final product been posted to the main site? [[/tab]] [[tab Scriptwriter Checklist]] +* Scriptwriter Checklist > **__Scriptwriter__** - The person who writes up the script. //This individual or group of individuals is responsible for creating the story, writing up the dialogue, "stage directions" (though here, unlike in theatre, it is a sound stage rather than a physical one), ensuring that the formatting is useable by everyone, and the like. This is the role most people on the wiki will be most familiar with, as it is the one closest to simply being a text author.// **Involved in:** Pre-production (consults on Production and Post-production) **Skills needed:** Writing skills **IMPORTANT NOTE:** Unlike in most SCP Foundation fiction, it is difficult to successfully pull of redaction in audio format. The script should include everything. If you want something redacted, then include what is redacted, but note that it is redacted so the mixing engineer can replace it. Example: > **AGENT:** We need to make sure that <REDACTED> the creatures don't get out and destroy the world. </REDACTED> Otherwise, we're all screwed. ++* **CHECKLIST** +++* Pre-production * Have you formatted the script in a manner which can be used by everyone else? (See the suggested formatting template below.) * Have you included a pronunciation guide? If something can be pronounced in more than one way, it will be; therefore, if you care, tell people how to pronounce things. (Putting the guide at the top of the script is a good plan.) * Have you listed casting information about the characters? While not every character needs this defined, and while the director is free to cast differently from indicated in the script, this is useful. This includes, but is not limited to: * Gender * Approximate age * Accent (as applicable) * Vocal range (Soprano, Alto, Tenor, Baritone, Bass) * Any additional information relevant to the sound of the character * Are the voice actor requirements feasible? In other words, is it possible to find actors capable of performing the script as written? * Have you included information about sound effects? * Have you received permission for use of SCPs, characters, and articles you did not create? * Has the script been peer reviewed for story and dialogue, at least by the Producer and Director? (If you are the Producer and Director in addition to the Scriptwriter, have you had at least two other people peer review the story?) * Has the script been peer reviewed for technical feasibility, at least by the Mixing Engineer? (If you are the Mixing Engineer in addition to the Scriptwriter, then you know your own abilities and limitations.) * Have you posted the finalized script to the collaborative project’s sandbox page? ++* Example Script Template Of course people are welcome to write audio scripts however they like, but this is a useful semi-standardized template for a format that is easy for a producer/director/sound engineer/actor to work from. **Example Script Template (Wiki code; copy & paste this into your sandbox):** ----- @<**Title:** (Work Title)>@ @<**Characters:**>@ @<* (Character A): Brief Description of Character A, including notes for voice actor casting>@ @<* (Character B): Brief Description of Character B, including notes for voice actor casting>@ @<* Etc.>@ @<**Script**>@ @<//(Description of ambiance, i.e. "Sounds of a forest at night")//>@ @<**CHARACTER A:** I say some line of dialogue here.>@ @<**CHARACTER B:** I say something else here, such as replying to Character A, or whatever.>@ @<//(Description of sounds heard, i.e. "A low howl is heard in the distance")//>@ @<**CHARACTER A:** Hey, did you hear that thing that sounded like a low howl in the distance?>@ (This continues) @<**FINAL NOTE:** An (optional) reference putting context into how the Foundation came to have this recording.>@ @<**End of script**>@ ---- **This, of course, would end up looking like this (when formatted):** ---- **Title:** (Work Title) **Characters:** * (Character A): Brief Description of Character A, including notes for voice actor casting * (Character B): Brief Description of Character B, including notes for voice actor casting * Etc. **Script** //(Description of ambiance, i.e. "Sounds of a forest at night")// **CHARACTER A:** I say some line of dialogue here. **CHARACTER B:** I say something else here, such as replying to Character A, or whatever. //(Description of sounds heard, i.e. "A low howl is heard in the distance")// **CHARACTER A:** Hey, did you hear that thing that sounded like a low howl in the distance? (This continues) **FINAL NOTE:** An (optional) reference putting context into how the Foundation came to have this recording. **End of script** ---- [[/tab]] [[tab Director Checklist]] +* Director Checklist > **__Director__** - The person who is in creative control of the production. //The director casts and directs the voice talent, decides yes or no on sound effects (SFX) and music, and oversees the project from a creative standpoint. (In "the real world" of production, the producer is usually the director's boss, though the director generally gets significant ability to set the direction of the project from an artistic standpoint. For our purposes, it is entirely conceivable that these may be the same individual, but this is not necessarily the case.)// **Involved in:** Pre-production, Production, Post-production **Skills needed:** Directing ability, people skills, administrative acumen, creative vision, patience, time ++* **CHECKLIST** +++* Pre-production * Have you found voice actors sufficient for the parts? * Have you agreed on an intended tone for the piece with the Producer and the Scriptwriter? +++* Production * Have you located a suitable (quiet) location for recording? * Are you constantly giving your actors feedback on what they are doing well and what they should change to do better? Remember, actors aren’t mind-readers. Talkative directors are helpful directors. * As it is conceivable you are recording conversations piecemeal, with actors not necessarily ever being in the same room, are you helping keep track of the tone and intensity of conversations the characters are having? Are you telling this to the actors? * Are you ensuring you get at least one good take of every line? Recording a scene need not be done continuously or in real-time; you can jump around. +++* Post-production * Have you communicated with the Mixing Engineer what your creative goals are for the project? * Have you found suitable sound effects? * Does the pacing seem right? Do the scenes move too slowly or too quickly? * Have you found suitable music which is usable under the Creative Commons License? [[span style="color:#880000;"]]Remember, copyright infringement that does not result in monetary gain is still illegal.[[/span]] If you are not using original or music with no copyright (such as classical music), then you should see either music released under Creative Commons or music “with rights” (sometimes called “cleared music”). This means purchasing the music also purchases the right to use it, not merely to listen to it. * Have you listened to the piece all the way through for content? * Have you listened to the piece all the way through for (volume) levels? * Have you listened to the piece all the way through for technical aspects? * From an artistic standpoint, are you happy with the final product? [[/tab]] [[tab Voice Actor Checklist]] +* Voice Actor Checklist > **__Voice Actor__** - Also known as the "talent", voice actors (the term is conventionally gender neutral) are the people being recorded playing the characters. **Involved in:** Production **Skills needed:** Acting ability (useful, though non-actors __can__ be voice actors), good diction, patience ++* **CHECKLIST** +++* Pre-production * Do you understand the piece? * Do you understand your character(s)? * Are you “being” the characters, rather than “acting as” the characters? If someone listening to you believes that you are the character, rather than that you are performing as the character, then you’re doing it right. Otherwise, try again. //Act realistically under unreal circumstances – Constantin Stanislavski.// * Do you understand how to pronounce everything? * Have you read through the entire script enough times to have a good command of it? If the Director has only given you a partial script (for enforced method acting), then have you read what you have several times through? +++* Production * Do you have a glass of water available? It should not be too cold, as cold water will cause your airway to contract, audibly changing the quality of your voice. * Do you understand that if you stumble while recording, you should back up to a good breaking point (beginning of a line or sentence) and start again? * Are you breathing? Normally? Don’t forget! * Are you acting as though you are in a theatre, rather than a recording booth? You need not project your voice, as the microphone is right in front of you. In some ways, acting to a microphone is a lot more like talking normally than acting in a performance hall. * Are you happy with the take(s)? [[/tab]] [[tab Recording Engineer Checklist]] +* Recording Engineer Checklist > **__Recording Engineer__** - The person who handles recording the audio of the voice actor[s] and/or SFX artists. //If you're sitting recording yourself on your laptop's microphone, then you're the recording engineer, in addition to the voice actor.// **Involved in:** Production, Post-production **Skills needed:** Ability to use digital recording equipment (it can be helpful to know how to do basic cuts in Audacity or the like, but this is by no means necessary) ++* **CHECKLIST** +++* Production ++++* Before Actually Recording * Is the recording space suitable? * Have all sources of background noise been removed/minimized? * Has everything been set up? ++++* During Recording * Have you tested the equipment? * Have you recorded 30 seconds of “room”? * Is the microphone placed properly relative to the actor? * Are you slating takes? * Are you keeping script and take notes? +++* Post-production * Have you forwarded uncompressed, lossless (DO NOT USE MP3 FILES, USE WAV FILES) raw audio files to the Mixing Engineer? * Have you forwarded all script/take notes to the Mixing Engineer? [[/tab]] [[tab Mixing Engineer Checklist]] +* Mixing Engineer Checklist > **__Mixing Engineer__** - The person who takes all the raw source audio and mixes it together into the final product. //This person is not necessarily the recording engineer, since production and post-production are separate parts of the process. The recording engineer works in production; the mixing engineer works in post. Mixing engineers tend to have to spend many hours putting tracks together - from a technical standpoint, they usually have the most work. __Making their lives easier is a good idea__.// **Involved in:** Post-production **Skills needed:** Advanced audio editing / mixing skills, time, patience, a good ear, time, mixing software, patience, creativity, time ++* **CHECKLIST** +++* Post-production * Has all necessary raw parts been received? * Is the dialogue cut? * Is the SFX cut? * Has the rough mix (no music) been created? * Have the levels been set? * Has the rough mix been approved by the director and the producer? * Has the music been cut? * Has the music been added into the mix? * Have the levels been altered to account for the music? * Has the tentative final mix been approved by the director and producer? * Have the levels been checked again? * Has the final cut been reviewed for content? * Has the final cut been reviewed for technical aspects? * Has the end product been posted to the main site? [[/tab]] [[/tabview]] ---- + Audio Dramas: The Genre [[tabview]] [[tab Overview]] ++* Overview > ““Nothing is so frightening as what’s behind a closed door, [William F. Nolan] said. You approach the door in the old, deserted house, and you hear something scratching at it. The audience holds its breath along with the protagonist as she/he approaches the door. The protagonist throws it open, and there is a ten-foot-tall bug. The audience screams, but this particular scream has an oddly relieved sound to it. “A bug ten feet tall is pretty horrible,” the audience thinks, “but I can deal with a ten-foot-tall bug. I was afraid it might be a //hundred// feet tall.” …What’s behind the door or lurking at the top of the stairs is never as frightening as the door or staircase itself. And because of this, comes the paradox: artistic work of horror is almost always a disappointment. It is the classic no-win scenario. You can scare people with the unknown for a long, long time, but sooner or later, as in poker, you have to turn your cards up. You have to show the audience what’s behind it... > > “There is and always has been a school of horror writers (I am not among them) who believe that the way to beat this rap is to never open the door at all. **…The exciting thing about radio at its best was that it bypassed the question of whether to open the door or leave it closed. Radio, by the very nature of the medium, was exempt.** For the listeners during the years 1930 to 1950 or so, there were no visual expectations to fulfill in their set of reality.” > - //Stephen King, __Danse Macabre__//, emphasis added Audio, as King expresses, is a well suited medium for the genre of horror. The audience, deprived of the visual, is able to imagine the objects of their terror. Audio is different from video in having different conventions in its mode of storytelling, however, which can be disconcerting to audiences accustomed to the false dichotomy of text-based and visual storytelling. [[/tab]] [[tab Four Types of Scares]] ++* Four Types of Scares > “Terror on top, horror below it, and lowest of all, the gag reflex of revulsion. My own philosophy as a writer of horror fiction is to recognize these distinctions because they are sometimes useful, but to avoid any preference for one over the other on the grounds that one effect is somehow better than another. The problem with definitions is that they have a way of turning into critical tools—and this sort of criticism, which I would call criticism-by-rote, seems to me needlessly restricting and even dangerous. I recognize terror as the finest emotion… and so I will try to terrorize the reader. But if I cannot terrify him/her, I will try to horrify; and if I cannot horrify, I’ll go for the gross-out. I’m not proud.” > -//Stephen King, __Danse Macabre__// In his non-fiction book //Danse Macabre// (a fine work I highly recommend for any aspiring horror writer), Stephen King divides scares into three types: terror, horror, and revulsion. I will humbly add a fourth - shock/surprise - which does not neatly fit in any of his three categories but is present in horror fiction nonetheless. +++* Terror > “The finest emotion is terror, that emotion which is called up in the tale of The Hook and also in that hoary old classic, “The Monkey’s Paw.” We actually //see// nothing outright nasty in either story; in one we have the hook and in the other there is the paw, which, dried and mummified, can surely be no worse than those plastic dogturds on sale at any novelty shop. It’s what the mind sees that makes these stories quintessential tales of terror. It is the unpleasant speculation called to mind when the knocking on the door begins in the latter story and the grief-stricken old woman rushes to answer it. Nothing is there but the wind when she finally throws the door open… but what, the mind wonders, //might// have been there if her husband had been a little slower on the draw with that third wish?” > - //Stephen King, __Danse Macabre__// In audio format, terror is caused by absence more than presence. The absence of sound, or the absence of explanation. We know the monster is out there, but all we hear are crickets in the night. When is it going to appear? Alternatively, we hear the banging at the door. We don’t know what beastie is trying to get in, but it cannot be good. Terror also applies to the moment of dawning comprehension where the audience realizes that their preconception was wrong and the situation is worse than they originally feared. The banging on the door is not coming from a monster trying to get inside – the monster is already inside. That scene in //Aliens// where the characters are briefly confused how the monsters could be inside the room, as their motion detectors say. The moment of “oh, crap!” when they realize the aliens are above them in the air ducts – that is terror. Audio also provides an opportunity for terror many media lack: the ability to abruptly remove stimuli. If one is listening to a scene where the characters are walking through the woods at night, the background ambience would likely include crickets and/or frogs, the occasional owl, and similar. If that suddenly disappears, either by fading out or by an abrupt cut (as would occur if one hit the “pause” button), that itself can inspire terror in the audience. +++* Horror > “…Horror, that emotion of fear that underlies terror, an emotion which is slightly less fine, because it is not entirely of the mind. Horror also invites a physical reaction by showing us something which is physically wrong… As we have already pointed out, the old man in “The Monkey’s Paw” is able to wish the dreadful apparition away before his frenzied wife can get the door open. In //Tales from the Crypt//, the Thing from Beyond the Grave is still there when the door is open wide, big as life and twice as ugly.” > - //Stephen King, __Danse Macabre__// In audio format, if terror is caused by absence, horror is caused by presence. We hear the monsters – the shrieks, the screams, the snarls – and we “see” them as well (perhaps more aptly, the characters see them, and we hear the characters’ descriptions and reactions). This can be quite difficult to pull off well. A zombie might be scary, but the sound of a low moan “Ooouuuuunnnnnggghhhrrrrrrr” is unlikely to scare an adult. Since the rise of television in the 1950s, we have become accustomed to being scared by horrific sights rather than horrific sounds. Therefore, creativity is needed. //Stargate SG-1// does a good job of creating horror-inspiring sounds with its replicators. The eeeTICK eeeTICK eeeTICK sound of each mechanical spider’s legs is scary enough; multiply it thousands of times and it becomes nightmare inspiring. +++* Revulsion > “There is a third level—that of revulsion. This seems to be where the “chest-burster” from //Alien// fits… the gross-out.” > - //Stephen King, __Danse Macabre__// Again, we as a society have become accustomed to disgusting sights more than disgusting sounds. In some ways, this is a boon to audio. Drips, squelches, and other disgusting sounds can be as effective or more than gallons of fake blood in a visual medium. And, unlike the visual, the source of the sound need be nothing like that for which it stands in. A sound effects guru acquaintance of mine once needed to create the sound of a man’s skin being turned inside out. He put on some rubber gloves and recorded the sound of peeling them off, inside out. When played back without the visual stimulus of the gloves being removed, it was disturbingly believable. +++* Shock/Surprise This is when something scares the audience by startling them. In an audio format, sudden sounds fall here. Jump scare chords, unexpected sound effects, and the like all fall into this category. Use these judiciously; overuse rapidly becomes irritating and drives away audiences. [[/tab]] [[tab Styles of Story]] ++* Styles of Storytelling in Audio Dramas The different styles of storytelling which appear with audio depend in no small part on the role of the microphone in the production. Is the microphone supposed to really be there, recording things? Or is it a disembodied phantom ear, through which the audience eavesdrops on characters who believe themselves to be alone. Two common conventions present in all aspects of audio storytelling are the use of narration and dialogue-as-exposition. Though incredibly common in audio, these have disappeared from most television and films, so they can be a little jarring to modern audiences. In the Will Smith version of //I Am Legend//, no character exclaims “holy crap, they just blew up the Brooklyn Bridge!” as it is unnecessary: the audience just watched it happen. In an audio version of the same scene, such an exclamation would be nearly required, as otherwise the audience merely heard “kaBOOM” with no explanation. We are so visually-oriented these days that it can take getting used to hearing description provided by either narration or dialogue-as-exposition, since it is something we don’t experience in daily life. But if it is not included in audio storytelling, the audience is all but lost. +++* Audio Book A format perhaps best described as “book on tape”, the audio book is what results when a book (or short story, or the like) is read into a microphone. Variations include those works read by a single individual (possibly doing different character voices, such as Jim Dale’s reading of the Harry Potter series) and those where the book is carved up into a pseudo-play, with different actors reading different characters and someone reading the narration (possibly but not necessarily with the addition of sound effects). In audio books, there is no attempt to imply to the audience that what they are hearing is “real” rather than a performance of an existent work of fiction. The presence of the microphone is not justified by some in-universe convention; it simply is the way the work was recorded. +++* Faux Newscast //We interrupt this program with a special news bulletin!// This style was made famous by the first half of the (in)famous 1938 “War of the Worlds” broadcast produced by Orson Welles for CBS Radio (note, however, that the far less famous second half of the broadcast does //not// fall into the faux newscast style; it is far more like an audio book or radio drama, with Orson Welles reading narration). The justification for the source of the audio is what one would hear if one were to turn on their radio set if the events occurring in the story were actually occurring. Thus, the microphone can only pick up what the reporters would be able to record. As was discovered during the Welles broadcast, people can and do believe faux newscasts if they are handled improperly, which has resulted in a variety of restrictions on broadcast hoaxes. Interviews fall into the same conventions as faux newscasts. +++* Found Footage Made famous by the independent film //Blair Witch Project//, found footage pretends to be actual material which was recorded by a viewpoint character who usually (but does not always) died, and the footage was subsequently found. Another famous example is the “helmet cam” recording from the first //Halo// game, immediately before the appearance of the Flood. Like the faux newscast, the creators of the story work to maintain the illusion that the material was really recorded and that the events depicted actually happened, so the presence of the microphone must be justified. Recordings of test logs made by researchers would generally be subject to found footage conventions. +++* Radio Drama This style appropriates many aspects of theatre. Though some productions push for realism – the audience is secretly watching (listening) through an invisible fourth wall, being voyeurs into the characters’ lives – this is far from required. Narrators are common. There is no justification required for the presence of the microphone, and the audience is expected to not question this any more than a patron of the theatre might question why they can see into the Brewster’s living room in the stage play //Arsenic and Old Lace//. [[/tab]] [[/tabview]] ---- + Science of Audio ++ Six Properties of Sound //This section is adopted from lecture notes from __Music 108: Introduction to Music Technology__, taught by John Ellinger, at Carleton College.// [[tabview]] [[tab Introduction]] +++* Six Basic Properties of Sound # Frequency # Amplitude # Timbre # Duration # Envelope # Location **__Frequency__** refers to how high or how low the note sounds (pitch). The term pitch is used to describe frequencies within the range of human hearing. **__Amplitude__** refers to how loud or soft the sound is. **__Duration__** refers to how long a sound lasts. **__Timbre__** (pronounced TAM-burr) refers to the characteristic sound or tone color of an instrument. A violin has a different timbre than a piano. **__Envelope__** refers to the shape or contour of the sound as it evolves over time. A simple envelope consists of three parts: attack, sustain, and decay. An acoustic guitar has a sharp attack, little sustain and a rapid decay. A piano has a sharp attack, medium sustain, and medium decay. Voice, wind, and string instruments can shape the individual attack, sustain, and decay portions of the sound. **__Location__** describes the sound placement relative to our listening position. Sound is perceived in three dimensional space based on the time difference it reaches our left and right eardrums. These six properties of sound are studied in the fields of music, physics, acoustics, digital signal processing (DSP), computer science, electrical engineering, psychology, and biology. [[/tab]] [[tab Terminology]] +++* Terminology ++++* MIDI MIDI (**M**usical **I**nstrument **D**igital **I**nterface) is a hardware and software specification that enables computers and synthesizers to communicate through digital electronics . The first version of the MIDI standard was published in 1983. MIDI itself does not produce any sounds, it simply tells a synthesizer to turn notes on and off. The quality of the sounds you hear are dependent on the sounds built into the synthesizer. Cheap MIDI synthesizers sound like toys. Expensive MIDI synthesizers can realistically reproduce a full orchestra, however they may cost over $10,000. The MIDI Manufacturers Association (www.midi.org) is in charge of all things MIDI. ++++* Digital Audio Digital audio is a mix of mathematics, computer science, and physics. Sound waves we hear are represented as a stream of numbers. An Analog Digital Converter (ADC) converts an analog signal (e.g., voltage fluctuations from a microphone) into numbers that are sent to a computer. The computer processes the numbers and sends them on to a Digital Analog Converter (DAC). The DAC converts the numbers back into an analog signal that drives a speaker. [[image DAWSignalChain.png]] ++++* Analog and Digital Signals An analog signal is a continuous signal. A digital signal is a discrete signal. Analog signal values are known for all moments in time. Digital signals are only known at certain specified times. [[image graphContinuous.png title="Continuous analog signal"]] [[image graphDiscrete.png title="Discrete digital signal"]] ++++* Prefixes These prefixes refer to numerical quantities. For example a 1 gigahertz computer's CPU is timed with a clock running in nanoseconds. Or, a slow digital audio recorder can record 23 samples every microsecond. ||~ Prefix ||~ Value ||~ Abbreviation || ||Tera || 1,000,000,000,000 || T || ||Giga || 1,000,000,000 || G || ||Mega || 1,000,000 || M || ||Kilo || 1,000 || K || || || || || ||Milli || 0.001 || m || ||Micro ||.000001 || μ || ||Nano ||.000000001 || n || ||Pico ||.000000000001 || p || [[/tab]] [[tab Frequency]] +++* Frequency Frequency is measured in Hertz (Hz). One Hz is one cycle per second. Human hearing lies within the range of 20Hz - 20,000Hz. Those sounds in excess of 20 KHz are known as ultrasound (medical diagnostic ultrasound imaging usually employs frequencies between 2 and 18 MHz). Those sounds with a frequency lower than 20 Hz are referred to as infrasound (there are some theories that some ghost sightings may be caused by infrasound sources, as the human eyeball’s resonant frequency is about 18 Hz). As we get older the upper range of our hearing diminishes. Human speech generally falls in the range from 85 Hz - 1100 Hz. Two frequencies are an octave apart if one of them is exactly twice the frequency of the other. These frequencies are each one octave higher than the one before: 100Hz, 200Hz, 400Hz, 800Hz, and 1600Hz. ++++* Frequency in Music Frequency and pitch are often thought to be synonymous. However, there is a subtle distinction between them. A pure sine wave is the only sound that consists of one and only one frequency. Most musical sounds we hear contain a mix of several harmonically related frequencies. Nonetheless, musical frequencies are referred to as pitch and are given a names like "Middle C" or "the A above Middle C". The frequency spectrum used in music is a discrete system, where only a select number of specific frequencies are used. For example, the piano uses 88 of them from 27.5 Hz to 4186 Hz. The modern system of tuning is called Equal Temperament and divides the octave 12 equal parts. The frequency ratio between any two neighboring notes is [[$ 2^{1\over 12} $]]. [[image 01Piano.GIF]] The higher the frequency, the higher the pitch. The lower the frequency, the lower the pitch. High pitches are written higher on the musical staff than low pitches. High notes on the piano are on the right, and low notes are on the left as you're facing the piano. Low frequency = low pitch [[image 02LowFreq.png title="Low Frequency (Low Pitch)"]] High frequency = high pitch [[image 03HiFreq.png title="High Frequency (High Pitch)"]] ++++* Frequency in MIDI MIDI represents frequency as a MIDI note number corresponding to notes on the piano. The 88 keys on the piano are assigned MIDI note numbers 21-108, with middle C as note number 60. You can move up or down an octave in MIDI by adding or subtracting 12 from the MIDI note number. MIDI is capable of altering the frequency of a note using using the "pitch bend" command. A MIDI Tuning Extension permits microtonal tuning for each of the 128 MIDI note numbers. However, not all synthesizers support micro tuning. ++++* Frequency in Digital Audio Physics and digital signal processing (DSP) deal with very large frequency ranges. The audio spectrum is a very small part of that range, a relatively narrow band between 20 - 20,000 Hz. The Audio band spans 20000 ([[$ 2 \times 10^4 $]]) Hz out of a total bandwidth of [[$ 10^{20} $]] Hz. Because of the extreme differences between audio waves and gamma waves, a logarithmic scale was used for the graph. [[image FrequencySpectrum.png]] The "purest" pitched tone is a sine wave. The formula for a sampled sine wave is shown below where n is a positive integer sample number, f is the frequency in Hz, SR is the sampling rate in samples per second, and θ is the phase in radians. [[math]] SineWave(n) = \sin \left( 2 \pi f {n\over SR} + \theta \right) [[/math]] Many complex tones can be generated by adding, subtracting, and multiplying sine waves. Any frequency is possible and any tuning system is possible. You could divide the octave into N parts with a frequency spacing of [[$ 2^{1\over N} $]] between notes instead of the twelve equally spaced half steps used in Equal Temperament. [[/tab]] [[tab Amplitude]] +++* Amplitude The amplitude of a sound is a measure of its power and is measured in decibels. We perceive amplitude as loud and soft. Studies in hearing show that we perceive sounds at very low and very high frequencies as being softer than sounds in the middle frequencies, even though they have the same amplitude. Amplitude in Music The musical term for amplitude is dynamics. There are nine common music notation symbols used to represent dynamics. From extremely loud to silence they are: * fortississimo - as loud as possible * fortissimo - very loud * forte - loud * mezzo forte - medium loud * mezzo piano - medium soft * piano - soft * pianissimo - very soft * pianississimo - as soft as possible * rest - silence The pianoforte is the ancestor of the modern piano and was invented in Italy around 1710 by Bartolomeo Cristofori. It was the first keyboard instrument that could play soft (piano) or loud (forte) depending on the force applied to the keys, thus its name. If it had been invented in England we might know it as the softloud. ++++* Amplitude in MIDI The MIDI term for amplitude is velocity. MIDI velocity numbers range from 0-127. Higher velocities are louder. 0 is silent. ++++* Amplitude in Digital Audio The amplitude of a sound wave determines its relative loudness. Looking at a graph of a sound wave, the amplitude is the height of the wave. These two sound waves have the same frequency but differ in amplitude. The one with the higher amplitude sounds the loudest. Low amplitude = soft sound [[image 04LoAmp.png title="Low Amplitude (Quiet)"]] High amplitude = loud sound [[image 05HiAmp.png title="High Amplitude (Loud)"]] Amplitude is measured in decibels, so named from the prefix “deci” and the base unit Bel (named after Alexander G. Bell) – this is why decibels are abbreviated dB. Decibels have no physical units, they are pure numbers that express a ratio of how much louder or softer one sound is to another. Because our ears are so sensitive to a huge range of sound, decibels use a logarithmic rather than a linear scale according to this formula. [[$ dB=20 \log_{10}\left(\frac{{Amplitude}_1}{{Amplitude}_2}\right) $]] Positive dB's represent an increase in volume (gain) and negative dB's represent a decrease (attenuation) in volume. Doubling the amplitude results in a 6 dB gain and the sound seems twice as loud. Halving the amplitude results in a 6 dB attenuation, or a -6 dB gain, and the sound seems half as loud. When the amplitude is changed by a factor of ten the decibel change is 20 dB. Every 10 decibel change represents a power of ten increase in sound intensity. For example, the intensity difference between the softest symphonic music (20 dB) and loudest symphonic music (100 dB) differs by a factor of 100,000,000 (10 to the 8th power). This table shows some relative decibel levels. Read 10^3 as . ||~ Decibels (Logarithmic Scale) ||~ Magnitude (Linear Scale) ||~ Description || || 160 || 10^16 || || || 150 || 10^15 || || || 140 || 10^14 || Jet takeoff || || 130 || 10^13 || || || 120 || 10^12 || Threshold of pain, Amplified rock band || || 110 || 10^11 || || || 100 || 10^10 || Loudest symphonic music || || 90 || 10^9 || || || 80 || 10^8 || Vacuum Cleaner || || 70 || 10^7 || || || 60 || 10^6 || Conversation || || 50 || 10^5 || || || 40 || 10^4 || || || 30 || 10^3 || || || 20 || 10^2 || Whispering, Softest symphonic music || || 10 || 10^1 || || || 0 || 10^0 || Threshold of hearing || __Digital audio often reverses the decibel scale making 0 dB the loudest sound that can be accurately produced by the hardware without distortion.__ Softer sounds are measured as negative decibels below zero. Software decibel scales often use a portion of the 0 dB to 120 dB range and may choose an arbitrary value for the 0 dB point. This dB scale is found in the Logic Pro software. The dB scale on the left goes from 0 dB down to -60 dB. The 0.0 dB setting on the volume fader on the right corresponds to -11 dB on the dB scale. [[image LogicProMeter.png]] When recording digital audio, you always want the sound to stay under well under 0 dB. Notice the flat tops on the signal on the left at the 0 dB mark. That's referred to as digital clipping and it sounds terrible. The screen shots were captured using the open source cross platform software Audacity. (http://audacity.sourceforge.net/) [[image ClippedSignal.png title="Same sound twice, but the one on the left suffers from clipping"]] [*http://scp-wiki.wdfiles.com/local--files/col-hornby-s-audio-guide/piano_A3d.mp3 Sound with clipping] [*http://scp-wiki.wdfiles.com/local--files/col-hornby-s-audio-guide/piano_A3.mp3 Sound without clipping] [[/tab]] [[tab Timbre]] +++* Timbre Timbre (pronounced **TAM**-burr) refers to the tone color of a sound. It's what makes a piano sound different from a flute or violin. The timbre of a musical instrument is determined by its physical construction and shape. Sounds with different timbres have different wave shapes. Here are the waveforms of several different instruments playing the pitch A440. Piano [[image 08Piano.GIF title="Waveform of a piano playing A440"]] Violin [[image 09Violin.GIF title="Waveform of a violin playing A440"]] Flute [[image 10Flute.GIF title="Waveform of a flute playing A440"]] Oboe [[image 11Oboe.GIF title="Waveform of an oboe playing A440"]] Trumpet [[image 12Trumpet.GIF title="Waveform of a trumpet playing A440"]] Electric Guitar [[image 13ElecGtr.GIF title="Waveform of an electric guitar playing A440"]] Bell [[image 14Bell.GIF title="Waveform of a bell playing A440"]] Snare Drum [[image 15Snare.GIF title="Waveform of a snare drum playing A440"]] ++++* Timbre in Music Timbre in music is specified as text in the score, like Sonata for flute, oboe and piano. Timbre changes may be specified in the score as special effects like growls, harmonics, slaps, scrapes, or by attaching mutes to the instrument. ++++* Timbre in MIDI Timbre in MIDI is changed by pushing hardware buttons or sending a MIDI message called the Patch change command. ++++* Timbre in Digital Audio Different timbres have different squiggly waveform shapes. More precisely, timbre is defined by the relative strength of the individual components present in the frequency spectrum of the sound as it evolves over time. The method of obtaining a frequency spectrum is based on the mathematics of the Fourier transform. The Fourier theorem states that any periodic waveform can be reproduced as a sum of a series of sine waves at integer multiples of a fundamental frequency with well-chosen amplitudes and phases. [[$ \frac{a_0}{2} + \sum_{n=1}^\infty \, [a_n \cos(nx) + b_n \sin(nx)] $]] The pure mathematics sum would have an infinite number of terms. However, in digital audio a reasonable number works quite well. The Fast Fourier Transform (FFT) is arguably the single most important tool in the field of digital signal processing. It can convert a sampled waveform from the time domain waveform into the frequency domain and back again. By adjusting and manipulating individual components in the frequency domain it is possible to track pitch changes; create brand new sounds; create filters that modify the sound; morph one sound into another; stretch the time without changing the pitch; and change the pitch without affecting the time. Within the last 10 years, desktop computers have become fast enough to process these DSP effects in real time. Here are three spectrum views of a violin playing the note A440. The standard FFT displays the frequency spectrum. You can see three prominent peaks near 440 Hz, 880 Hz, and 1320 Hz. Those are the first three notes of the harmonic series, f, 2f, and 3f, when f equals 440 Hz. The sonogram displays the same data plotted with time on the X axis and frequency on the Y axis. The spectrogram displays the same data with the axes reversed from the sonogram. Standard FFT [[image ViolinSingleFFT.png]] Sonogram [[image ViolinSonogram.png]] Spectrogram [[image ViolinSpectrogram.png]] These screen shots were captured in the open source, cross platform sound editor Snd. (https://ccrma.stanford.edu/software/snd/) [[/tab]] [[tab Duration]] +++* Duration When we talk about duration we're talking about time. We need to know two events related to the time of a sound, when did it start and how long did it last. In music and digital audio, time usually starts at zero. How time is tracked is usually a variation on chronological time or proportional time. Here are some examples. > **Chronological Time or Clock Time** > "When I heard the first sound, I looked at my digital watch and it was 4:25:13. When I heard the second sound it was 4:25:17. The first sound had already stopped by then." > We know the starting time of both sounds but we don't know when the first sound stopped. > **Difference Time or Elapsed Time** > "When I heard the first sound, I started the digital timer on my watch. The sound ended exactly 1.52 seconds later. I heard the second sound a little later but wasn't able to reset the timer." > We know the duration of the first sound but we don't know the exact time either the first or second sound started. > **Proportional Time** > "I just happened to be taking my pulse when I heard the first sound. I was on pulse count 8. Because I was also looking at my watch, I also noticed the time was 4:25:13. I kept counting my pulse and the sound stopped after four counts. I heard the second sound start four counts later. I had just been running and my pulse rate was a fast 120 beats a minute." > We know the first sound started at time 4:25:13 and lasted for 4 pulses or 2 seconds. We know that the second sound started 2 seconds after that. ++++* Duration in Music The proportional time example is very similar to the way time is kept in music. A metronome supplies a steady source of beats separated by equal units of time. One musical note value (often a quarter note) is chosen as the beat unit that corresponds to one click of the metronome. All other note values are a proportional to that. Metronome clicks can come at a slow, medium, or fast pace. The speed of the metronome clicks is measured in beats per minute and is called the tempo. Whether the tempo is slow or fast, the rhythmic proportions between the notes remains the same. The actual duration of each note expands or contracts in proportion to the tempo. ++++* Duration in MIDI Time is not defined in the MIDI standard. The software uses the computer clock to keep track of time, often in milliseconds, sometimes in microseconds. Here's a recipe (pseudo code) to play two quarter notes at a tempo of 60. # Check the song tempo. It's 60 beats per minute so each quarter note lasts 1000 milliseconds. # Set the computer clock to 0. # Send a Note On message (NON) for the first note. # Keep checking the clock and wait until the clock reads 1000 milliseconds. # Send a Note Off message (NOF) to turn off the first note. # Send a NON message to turn on the second note. # Keep checking the clock and wait until the clock reads 2000 milliseconds. # Send a NOF message to turn off the second note. ++++* Duration in Digital Audio Duration in digital audio is a function of the sampling rate. Audio CD's are sampled at a rate of 44,100 samples per second with a bit depth of 16. Bit depth refers to the range of amplitude values. The largest number that can be expressed in sixteen bits is 216 or 65,536. To put audio sampling in perspective, let's graph of one second of sound at the CD sampling rate and bit depth. Start with a very large piece of paper and draw tick marks along X axis, placing each tick exactly one millimeter apart. You'll need 44,100 tick marks which will extend about 44.1 meters (145 feet). Next you need place tick marks spaced one millimeter apart on the Y axis to represent the 16 bit amplitude values. Let's put half the ticks above the X axis and half below. You'll need 32.768 meters (about 107 feet) above and below the X axis. Now draw a squiggly wave shape above and below the X axis, from the origin to the end of the 44100th sample while staying within the Y axis boundaries. Next carefully measure the waveform height in millimeters above or below the X axis at every millimeter sample point point along the 145 foot X axis. Write these numbers down in a single file column. You've just sampled one second of a sound wave at the CD audio rate. It probably took longer than one second; definitely not real time sampling. Digital sampling is done with specialized hardware called an Analog to Digital Converter (ADC). The ADC electronics contain a clock running at 44100 Hz. At every tick of the clock, the ADC reads the value of an electrical voltage at its input which is often a microphone. That voltage is stored as a 16 bit number. Bit depths of 24 are also used in today's audio equipment. A bit depth of 24 can use 16,777,216 different values to represent the amplitude. The counterpart to the ADC is the DAC (Digital to Analog Converter) that converts the sample numbers back into an analog signal that can be played through a speaker. Most modern computers have consumer quality ADC and DAC converters built in. Professional recording studios use external hardware ADC's and DAC's that often cost thousands of or tens of thousands of dollars. [[/tab]] [[tab Envelope]] +++* Envelope The term envelope is used to describe the shape of a sound over the life of the note. Does it start abruptly or gradually? Does it sustain uniformly? Does it die away quickly or slowly? ++++* Envelope in Music The performers touch or breath can shape the envelope of a musical sound. Another term for this is articulation. ++++* Envelope in MIDI A sound envelope in MIDI may be built in to the sound itself or it may be controlled through an Attack, Decay, Sustain, Release (ADSR) envelope. ADSR envelopes can sometimes be adjusted by tweaking knobs and buttons on the hardware or in the software. An ADSR envelope can be simulated in MIDI with volume or expression control messages. ++++* Envelope in Digital Audio The envelope of a sound is the outline of the waveform's amplitude changing over time as seen on an oscilloscope or in sound editing software. [[image envelope.png]] You can mathematically "envelope" a waveform by creating a second wave (amplitude values 0-1) that represents the envelope. The second wave must be the same duration as the first wave. When you multiply the samples of the original wave by the envelope wave, you create a third waveform conformed to the shape of the envelope. [[image ViolinEnvelope.png]] Many sound editing software programs have functions to create sound envelopes. [[image EnvelopeAudacity.png]] [[/tab]] [[tab Location]] +++* Location Location refers to the listener's perception of where the sound originated. ++++* Location in Music The location of the sound is usually not specified in the score but is determined by the standing or seating arrangement of the performers. ++++* Location in MIDI MIDI restricts the location of sound to the two dimensional left right stereo field. The MIDI Pan control message can be used to position the sound from far left to far right or anywhere in between. If the sound is centered, equal volumes appear in the left and right speaker. If more signal is sent to the left speaker than to the right speaker, the sound will be heard coming from the left. ++++* Location in Digital Audio Sophisticated mathematical formulas can create a three dimensional sound from two dimensional stereo headphones or speakers. Waveforms can be played with multiple delayed versions of themselves to simulate the reverberation characteristics of an acoustic space. [[/tab]] [[/tabview]] ++ "Lossy" versus "Lossless" From Wikipedia: > //Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. The term lossless is in contrast to lossy data compression, which only allows an approximation of the original data to be reconstructed, in exchange for better compression rates.// The short version here is that you want lossless data compression for your raw audio files (the final product to be posted to the main site can be compressed in a lossy format, but ONLY the Mixing Engineer should worry about that, and ONLY for the final product). Lossy runs into the copy-of-a-copy-of-a-copy degradation, which is a BIG problem when you're talking about mixing and remixing tracks over and over (which we are talking about). There are a bunch of different algorithms which work for lossless compression. For most purposes, .wav files are just fine. Be aware that .mp3 is lossy (which is why it is so much smaller than .wav). So, anything you're forwarding to the Mixing Engineer should be in .wav format. ---- + Troubleshooting [[tabview]] [[tab Introduction]] +++* Troubleshooting > Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law. > Hanlon's Razor: Never attribute to malice that which is adequately explained by stupidity. Murphy's Law states that "Anything that can go wrong will." Most people take this as a sign of pessimism. However, from a strict engineering standpoint, it makes sense that when planning something one should acknowledge all possible failure points and conditions which would cause such failures, and assume that at some point or another these conditions //will// be met and failure will occur. Therefore, the planner ought to determine a method for mitigating all possible failures. //As such, Murphy's Law is not pessimism but good planning.// Things will go wrong during an audio drama production. Here are a couple of the more common technical problems, and some associated solutions. [[/tab]] [[tab Digital Clipping]] +++* Digital Clipping [[image gotcha1_clipping01.png width=”300px” title="No clipping = Good"]] [[image gotcha1_clipping10.png width=”300px” title="Clipping = Bad"]] **Problem Class:** Obnoxious - Unsalvageable **Special Containment Procedures:** Digital clipping __cannot__ be fixed after-the-fact; it **MUST** be prevented up front. When recording audio, don't overtax the microphone. When mixing, ensure that the sum of added digital amplitudes does not exceed the the ±1 limit. Simply put: make turn the gain (volume) down until clipping is no longer occurring. **Description:** Digital clipping occurs when the amplitude of a wave exceeds the maximum number allowed for a given bit depth. In digital audio amplitudes must remain in the scaled range of ±1. Each wave used eight harmonics. When the waveforms are added the amplitudes are added. Any value over or under the ±1 limit is clipped to ±1. Clipped waveforms have flat tops and flat bottoms as can be seen in Audacity. Waveforms with flat tops distort the original sound. > **Note from Sound Engineer Fie Stee:** Digital clipping is bad! Digital clipping is bad! Digital clipping is bad! Digital clipping is bad! Digital clipping is bad! [[/tab]] [[tab Unwanted Background Noise]] +++* Unwanted Background Noise **Problem Class:** Mild - Unsalvageable **Special Containment Procedures:** Background sound must be contained during initial recording, as clean removal during post-production is difficult to impossible. Accordingly, the director and recording engineer must take the following steps: # Choose a location for recording with minimal background noise. Personnel should listen silently **both** with ears and to the microphone feed through monitoring over-ear ("earmuff") headphones for at least 30 seconds to confirm a location's viability. * A clothing-filled closet works amazingly well as an impromptu recording facility. # Position the microphone away from obvious sound sources. Recording next to a window, air vent, or buzzing florescent light is inadvisable. # Be aware of the microphone's directionality. * Most laptop microphones are cardioid microphones, meaning they are mildly directional (aimed towards the person seated at the computer). * Even the most directional mics have only limited directionality. Unlike a camera, which has a frame boundary, microphones pick up sounds outside their envelope (the "bubble" of space they record best) - they just pick up these sounds less distinctly. * Be aware of sound sources behind the intended subject. Recording a voice actor whose back is to an exterior window will result in outdoor sounds in the recording, even if the window is closed. # If a background noise interrupts recording (such as a train whistle, or passing siren, or the like), stop and wait for it to pass. # Unplug the refrigerator. Most recordings made in private residences, apartments, and dorm rooms have fridge hums in the background. You __will__ notice the difference. If you need a way of remembering to plug it back in, put your keys in the fridge when you unplug it; you won't leave without replugging it! # Position the microphone as close to the subject of the recording as possible. The closer the microphone is to the subject proportional to the distance from a background sound source, the higher the proportion of the intended sound verses background noise is recorded. **Description:** Save in the most well sound-insulated professional recording studios, most places have some background noise. Sources include (but are far from limited to) air handling units, refrigerators, florescent lights, computer fans and spinning drives, people, animals, wind, and so on. For practical purposes, no recording environment is truly silent. Human hearing is an inadequate judge of what might or might not be picked up by a microphone - recording engineers **must** check the sound through monitoring over-ear ("earmuff") headphones. Background sound, like all sound, is affected by the inverse-square law. > In acoustics, the sound pressure of a spherical wavefront radiating from a point source decreases by 50% as the distance r is doubled; measured in dB, the decreases is still 6.02 dB, since dB represents an intensity ratio. The behaviour is not inverse-square, but is inverse-proportional (inverse distance law): > > [[$ p \ \propto \ \frac{1}{r} \, $]] > > The same is true for the component of particle velocity v \, that is in-phase with the instantaneous sound pressure p \,: > > [[$ v \ \propto \frac{1}{r} \ \, $]] > > In the near field is a quadrature component of the particle velocity that is 90° out of phase with the sound pressure and does not contribute to the time-averaged energy or the intensity of the sound. The sound intensity is the product of the RMS sound pressure and the in-phase component of the RMS particle velocity, both of which are inverse-proportional. Accordingly, the intensity follows an inverse-square behaviour: > > [[$ I \ = \ p v \ \propto \ \frac{1}{r^2}. \, $]] Because of this, moving the microphone closer to the subject (i.e., the voice actor) will improve the signal-to-noise ratio, in effect minimizing (though not eliminating) the background sound. > **Note from Sound Engineer Fie Stee:** If the source audio is lousy, everything I do is a band-aid. So, unless you have a magic "make the background noise go away" button (I don't), then there's only so much I can do to hide background noise. [[/tab]] [[/tabview]] ---- + Further Reading / References ++* Audio Dramas * King, Stephen. //Danse Macabre//. New York: Berkley Books, 1981. * Chapter V: //Radio and the Set of Reality// (pp. 107-128) * McKee, Robert. //Story: Substance, Structure, Style, and The Principles of Screenwriting//. New York: HarperCollins, 1997. ++* Sound Engineering * Rose, Jay. //Producing Great Sound for Film & Video//. 3rd Edition. New York: Focal Press, 2008. ----