Waveforms

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Term: waveform

The generic term waveform means a graphical representation of the shape and form of a signal moving in a gaseous, liquid, or solid medium. For sound, the term describes a depiction of the pattern of sound pressure variation (or amplitude) in the time domain. In colloquial speech, waveform audio is often used to mean the recorded sound itself (not the graphical representation) to distinguish it from structured audio, e.g., MIDI (Musical Instrument Digital Interface) data.

The temporal frequencies of sound waves are expressed regarding cycles (or kilocycles) per second. The simplest waveform is the sine wave since it has only one frequency associated with it. The sound waves associated with, say, music, are constantly varying.

--http://www.digitizationguidelines.gov/term.php?term=waveformsound

If you want to display waveforms in Premiere, you need to make sure that the following is selected in the timeline

showwaveforms.jpg

...and then you can make them appear on the track in two different ways:

Sound waves can have the following characteristics.

 

 

refers to the strength or power of a wave signal. The "height" of a wave when viewed as a graph. Higher amplitudes are interpreted as a higher volume, hence the name "amplifier" for a device that increases amplitude.

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The number of times the wavelength occurs in one second. Measured in kilohertz (Khz), or cycles per second. The faster the sound source vibrates, the higher the frequency.

Higher frequencies are interpreted as a higher pitch. For example, when you sing in a high-pitched voice you are forcing your vocal chords to vibrate quickly.

Audio Levels: Below find an example of a normal audio waveform in Premiere:

goodlevels.jpg

The above shows audio levels that are strong, but not clipped. (overmodulated)

clippedaudioinpremiere.png

Above find audio waveforms that are showing clipped audio on the right.

If you are looking at a track with dialogue, you want to make sure that the levels are strong (not clipped) and that the sections between the dialogue have very low amplitude indicating a good signal to noise ratio.

premieredialogue.png

If you look at the waveforms on the right (showing a subject talking), you can see a good signal with very little noise between the waveform peaks.

To get a good signal to noise ratio (where the volume on your intended audio source is high, and the ambient sound is low), you need to get an appropriate microphone as close to your subject as possible.

--http://www.kessleru.com/blogroll/2014/7/25/signal-to-noise-improving-audio-for-video-production

--http://www.kessleru.com/blogroll/2014/7/25/signal-to-noise-improving-audio-for-video-production