Week One: Sound and Hearing - Posted on 2014-04-14 by Carmon Peery

I have learned so much in the two days of school and reading through the lesson in the active textbook than basic schooling. I have learned all about sound waves and how they pertain to Audio Engineering; how sound is made possible through the vibrations of a sound source displacing the air molecules around it. Knowing how sound reflects, absorbs and diffuses is very important when it comes to recording live music. Reflections are the explanation for how sound behaves when it comes into contact with objects or surfaces that impede its forward progress. Absorbing power is determined by the material used. Diffusion scatters sound depending on the desired affect! I now understand how they work and help out in the live room. I learned about waveform ADSR which stands for Attack Decay Sustain and Release. Attack is the time it takes for a sound to build up to its full amplitude. Decay is the time taken for the subsequent run down from the attack level to the designated sustained level. Sustain is the main duration of a note occurring after the attack decay until the note is released by the musician. Release is the amount of time it takes after the musician has stopped playing for a sound to return to silence. 

I also have learned a lot about hearing and the inner working of the ear. The Pinna (Latin for feather) is the outer ear. It helps localize the sound and filters out certain frequencies because of its shape. The Tympanic Membrane is the ear drum. Sound waves displace air molecules down through the external ear canal to the ear drum. A small flap of skin like material that acts like a diaphragm, receiving sound pressure waves and transmitting them to the three bones in the inner ear. The Cochlea is a snail shaped organ that contains reed-like fibers connected to hair follicles that vibrate at resonant frequency.

Psycho acoustics is the study of how sounds are perceived by the brain.I've learned that Timbre refers to the harmonic frequency content that makes up the sound of a specific instrument. Also, I have learned that Acoustic Beats occur when two sounds with slight frequency differences interact with each other and the result is an Audible Phase Interaction. Monophonic Sound Reproduction consists of listening to sound on a single speaker. Back when they used two tracks, they recorded music with only two mics and it was very hard perceive spatial elements and depth from a performance. Stereo Image is the perception of depth, space, and the ability to locate individual elements within a mix of a two-channel stereo recording. The sounds of all the instruments are equally heard and and make you feel, so to day, inside the music. It is way more powerful! 

Week one has been a success. I love the fact that it is one on one with my mentor, WHO IS AWESOME BY THE WAY! The way he teaches and explains things make it easier for me to learn and grasp onto the subject. He makes it fun! I am looking forward to get further into the program and be more hands on. Bring on week two!