Audio Engineering Fundamentals and Video Production Types

Video Production Comparisons

Differences: Institutional Video vs. Documentary

• Institutional/Industrial Video (1):
  • Duration: Shorter than documentaries.
  • Purpose: Promotional and reporting.
  • Assignment/Creation: Typically done by company members.
  • Target Market: Public linked to the business sector.
• Documentary (2):
  • Duration: Longer.
  • Purpose: To report and/or entertain.
  • Assignment/Creation: Made by the creator (independent or commissioned).
  • Target Market: Wider public audience.

Differences: Didactic Video vs. Documentary

• Didactic Video (1):
  • Duration: Shorter.
  • Purpose: To teach a specific skill.
  • Commissioning: Company or organization linked to the activity.
  • Target Market: Interested parties (e.g., students).
• Documentary (2):
  • Duration: Longer.
  • Purpose: To inform and entertain.
  • Commissioning: Commissioned by a production company.
  • Target Market: Larger audience.

Sound Technology and Production

The Sound Mixer Functions

The sound mixer performs the following operations:

1. Adjust input levels and impedances.
2. Adjust the output level (0% to 100%).
3. Make frequency corrections (Equalization).
4. Monitoring of a signal (visual or acoustic).
5. Provide phantom power for condenser microphones.
6. Locate each signal in the proper position within the "sound setting" of the stereo mix (Panning).

Operations in the Sound Mix

1. Equalization
2. Panning (Stereo Positioning)
3. Reverberation
4. Compression (Mastering)

Loudspeaker Types

• Dynamic Speaker:

  Generally cheaper and lower quality. It is based on the interaction of magnetic fields and currents. The force generated by the magnetic field perpendicular to the current flow through the coil is transmitted to a diaphragm, which is the element responsible for generating sound waves.

• Electrostatic Loudspeaker:

  Difficult and expensive to produce. The physical principle of function is straightforward: like charges repel, and different signs attract.

• Ribbon Speaker:

  Similar principle to the dynamic system. The main difference is that the driver itself, which carries the audio signal, is the diaphragm that produces the sound waves.

The Digital Signal Process

The digital signal is produced through the following processes, as appropriate:

1. Sampling
2. Quantization
3. Encoding
4. Compression

Sound Visualization and Audio Standards

Sound Visualization Techniques

Waveform Graphics

Waveform graphics present the amplitude variations of the sound wave over time. The horizontal axis represents time, and the vertical axis represents amplitude, intensity, or sound pressure.

The Spectrogram

The spectrogram represents the intrinsic structure of the sound. The horizontal axis represents frequency, and the vertical axis represents amplitude.

Visual Cues for Sound Analysis

1. Amplitude-intensity ratio.
2. Waveform relationship with timbre.
3. Discontinuities and regularities, such as excessive noise and distortion elements.
4. Noise versus stable parts (e.g., vowels versus consonants).

Dolby Audio Standards

Dolby Stereo

Dolby Stereo is a variation of the analog stereo system that allows the use of the standard stereo track of the tape, adding 4 channels together through signal encoding and matrix processes within the 2-track stereo system.

Channels included: L (Left), R (Right), C (Center), S (Surround).

Bandwidth: 100 Hz to 7 kHz.

Dolby Digital

Dolby Digital differs from Dolby Stereo (introduced in 1992). It features 6 real audio channels in optical format:

• 5 channels covering 20 Hz to 20 KHz.
• 1 channel dedicated to Low Frequency Effects (LFE), covering 3 Hz to 120 Hz.

Each track has a resolution of 16 bit and 48 KHz.