The Science and Engineering of Sound

Audio Signal

  • An electronic representation of the actual sound wave

Dynamic Microphone

  • In a dynamic microphone a thin diaphragm is connected to a coil of wire called a voice coil which is precisely suspended over a powerful magnet.
  • As the sound waves strike the diaphragm it cause it to vibrate, moving the voice coil through the magnetic field generated by the magnet which generates a small bit of electricity which is sent down the output leads.
  • This is the electromagnetic principle.
  • ADVANTAGE: They are simply constructed and can handle loud sources without much distortion.
  • DISADVANTAGE: They are weak when trying to capture soft distant sources because the diaphragm needs lot of sound energy to move.
  • DISADVANTAGE: dynamic microphones have a heavy diaphragm along with the additional weight of the coil of wire.
    • It therefore takes longer for the diaphragm to react to a sound wave due to the effects of inertia hence causing a less accurate recording.

Ribbon Microphone

  • Variation on the dynamic microphone.
  • Ribbon microphones are almost exclusively used in the studio, not for location audio.
  • Instead of using a coil, ribbon microphones use a small strand of very thin 2 microns thick aluminum ribbon.
  • ADVANTAGE: It is more responsive to high frequencies
  • DISADVANTAGE: It is fragile and prone to tearing

Condenser Microphone

  • There’s no coil.
  • Condensers use two charged plates, one fixed and one which can move acting like a diaphragm.
  • The two charged electric plates create what’s called a capacitor. As sound waves strike the electrically charged diaphragm, it moves in relation to the fixed plate changing its capacitance and generating a very small electric charge which is amplified inside the microphone.
  • This is the electrostatic principle.
  • ADVANTAGE: Because you’re not moving a coil, condensers can be more responsive in the high frequencies.
  • ADVANTAGE: Because you don’t have any magnets, condenser microphones can be made very small.
  • Because condensers work with electrically charged plates, that means they require some sort of outside power.
  • Some microphones have the option of an onboard battery while all condensers can utilitize something called Phantom Power.

Phantom Power

  • +48v of energy sent down the microphone cable to a condenser microphone from the audio recording or mixing board. This power enables the electrically charged diaphragm to move in response to sound waves.

Directional Response

  • Directional response is represented by something called a polar pattern.

Polar Pattern

  • Polar pattern is how well the microphone “hears“ sound from different directions.

“On Axis” and “Off Axis”

  • On axis is directly in front of the sound source.
  • Off axis is not directly in front of the sound source.

Omnidirectional Mics

  • This mic polar pattern is responsive to sound from all directions, you don’t have to be “on axis” to be picked up.
  • Lavalier and lapel mics are small condenser microphones with an omnidirectional pickup pattern that can be placed on a person.
  • Boundary mics are omnidirectional condenser mics. They are positioned flush with a surface that capture sound as it rolls off the flat surface. Boundary mics are used in stage production and conference tables.
  • ADVANTAGE: These mics are useful for picking up sound in a general area.
  • ADVANTAGE: Lavalier / lapel mics are small and can be placed just about anywhere.
  • ADVANTAGE: Boundary mics do not draw attention to themselves because they lay flat on the floor or wall.
  • DISADVANTAGE: They will pick up all the unwanted sound in the area.
  • DISADVANTAGE: Lavalier, lapel, and boundary mics won’t have the same richness of sound as a shotgun or studio condenser mic.

Directional Mics: Cardioid Pattern

  • Most basic pattern.
  • ADVANTAGE: Picks up what’s in front but not behind.
  • ADVANTAGE: It is suited for live performance as it picks up the sound on axis but won’t pick up what’s behind it, like crowd noise or feedback from a speaker.

Directional Mics: Hypercardioid and Supercardioid Patterns

  • More directional than cardioid.
  • Picks up the front and sides and rejects 150 degrees to the rear.
  • Shotgun mics are supercardioid.
  • ADVANTAGE: Great for recording location audio while trying to filter out some of the unwanted ambient sound.
  • DISADVANTAGE: Can exhibit strange phasing sound effects when used in small spaces.

Directional Mics: Figure 8 Pickup Pattern / Bi-directional

  • The polar pattern looks like a figure 8.
  • ADVANTAGE: Useful for certain musical applications or interviews with a person on each side of the mic.

A Day in My Life

Summary

For a whole 24-hour period, I was tasked with logging what I did with my time. That was the easy part; I just made sure to log what time I started and what time I stopped doing an activity that was obviously different from the last. The majority of the time spent on this project was to make the pie chart to display my time management and finding pictures, but before that I wrote and recorded a script. After some complications, I was able to put the slideshow and audio together (in iMovie instead of YouTube editor, though) and upload it. In the end, this project was really good to open my eyes to how much time I was actually spending on each activity in the day.

Script

There are twenty four hours in a day. 1 hour is equal to 4% of your day. I tracked my time for twenty four hours on my average school day to see how much of my time was being spent for what. Most of my time was spent at – surprise surprise – school. This was expected as I don’t really spend my time at home focused on the same thing for more than 7 hours. When I’m not at school a lot of my spending time is used for transportation.  It takes me 1 hour and 30 minutes to get to school and the same amount of time to get home. Plus an extra hour for walking to the bus stop, walking from the bus stop, walking to dance class, and the works. The time spent at those at places for my leisure I counted as part of my entertainment time, and that was recorded as about 13% of my day.. I also included games, TV, and other activities that have no effect on my skills or benefit me in strong ways. To put it more harshly, it’s free time I use to uselessly entertain myself. Activities in the day that I use to better myself and my skills I labeled as productivity. Productivity includes practicing music, practicing makeup, reading and writing, working on skills, and homework. I also use this time to manage my future free time if I have made plans with friends or family. The time I spend talking to friends and family I recorded as communication. On a normal school day I only spend about an hour to talk to friends and family through the phone or skype and rarely face to face. Finally, the last activity I try to do daily is exercise. Usually it’s about two hours as I have regular dance classes. The days I don’t have dance class I try to exercise to improve my dancing or just burn some energy so it’s easier to sleep at night. On a regular school day I have on and off sleep for about 5 hours. Maybe an hour nap here and there and then sleeping for three hours straight. My sleep schedule is very irregular so my average night of sleep is between 4 and 6 hours. Although I have been known to have a day in the month where I sleep 11 hours – probably to make up for my terrible sleeping habits. Of course there are many variables to my day because everyday is different; especially days I don’t have school. Sometimes I get more sleep and I don’t leave the house at all. Sometimes I go into town to run errands. Sometimes I use my day to focus on exercise. In fact a lot of my free days are filled mostly with entertainment, but I think that’s okay. They say everything in moderation, right? And I like to think happiness inspires productivity, and it’s important that my time is being used positively. Thanks for watching.

Storyboard

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Editing

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The Documentary

What I Learned

In this project, the time I spent I felt was well used. I managed my time of the project really well. However, I did not plan ahead for an issue with the audio to occur. With that, it was very frustrating to keep recreating the same audio/video only to have it deleted, not save, or simply not work. I decided, well over the due date, that I would just edit it in iMovie instead. Then I uploaded the video to YouTube and embedded it into my blog. Even with this complication, I still was able to learn the mechanics of YouTube editor and got even more used to Audacity and Creative Commons.

My Favorite Song

For this assignment, I was asked to pick my favorite song to pick apart. I have many different favorite songs ranging from rap all the way to musical theatre, so instead I chose a song that I recently discovered, loved, and has a very interesting sound to me. First the song starts with an intro that’s just 3 notes in progression with sound effects that sound almost like bird calls. As the intro moves farther, more and more is added, including some light chord progressions on what sounds like chimes. Then comes in a long static noise that drowns out most of the music. In my opinion, this part of the song is genius; the extreme sound of the static with harsh timbre that provides a scary feeling contrasts with the chimes that provide a light and airy feeling and this creates a calm eeriness – however much of an oxymoron that may be. The static also seems to rush the tempo (or at least try, as the beat stays the same) and gives a sense of stress.

After the static drowns out all of the music the song comes back in suddenly, and with a low electronic base sound and drum repetition. After a few measures of this (letting us get used to the sudden change I suppose), an edited male voice begins singing in a high pitched voice with many harmonies in different and lower keys. His voice also has a sense of static, as if he is standing too close to the microphone. The song is now using multitrack recording to layer the different sounds sounds and voices on top of each other, to mix and mash; the key – although minor – has elements and slight harmonies in major keys that add to the song and make it more confusing and creepy. I feel as if the song is almost trying to temp me.

This song doesn’t follow common song structures (especially with two intros and no bridge). If the Intro was called “D”, it would have a DABABB type structure. Other than that, though, it’s closest to an ABAB song structure.

It Might Get Loud

Mondial

“We start with the feeling, and everything flows from that”

Musicians featured in Sony’s “It Might Get Loud” described each guitar as their sound. The difference in the structure of the guitar can evoke senses of different feelings and different ideas the artists wishes to convey. For this reason, the guitar has been the core of most popular music for years, and it shows no signs of dying out any time soon.

Musician Jack White thinks of music and performance as a challenge. As he creates guitars and sound he wishes to take things that don’t make pretty music on their own and use it to describe the feelings he wants it to. He uses music to push himself.

In the late 1930’s, it is said that rock artists began to make blues music. This darker music with more minor keys and calmer tones displayed more sadness than rebellion from the guitar. But with all music, the artist can convey such emotion by just believing what his or her music is about, and sometimes that’s all it takes to make rock music.

 

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