compression - above the zero line

rarefaction - below the zero line

One cycle - one period of compression + one period of rarefaction

Frequency - represents pitch, measured in cycles per second. Higher the frequency, the higher the number of cycles

It is measured in Hz

Humans can hear up to 20 kHz

Amplitude - represents intensity, visually represented in a waveform by height

It is measured in dB

Sample rate - number of samples per second (e.g. 44.1 kHz)

Nyquist-Shannon sampling theorem – to accurately record/reproduce a sound, the sample rate must be at least twice the highest frequency of that sound 

You need at least 2 samples per cycle - one sample in each compression phrase, and one sample in each rarefaction phase

Foldback/aliasing is when there are less than 2 samples per cycle, and a lower frequency is created

Bit depth - number of bits of information in each sample. The more bits, the more accurate the recording and reproduction of the audio will be

 

Dynamic range – using more bits will allow you to measure greater heights. Each bit gives around 6 dB of dynamic range.

Therefore, 16-bit has a maximum dynamic range of 96 dB (16x6) while a 24-bit audio has a maximum dynamic range of 144 dB (24x6) 

Maximum dynamic range of a human being is 120-130 dB, therefore 24-bit is the best bet to record everything you want to hear and more 

In Pro Tools, if the master file is on a local drive, it’s called a session file. 

If it’s in the cloud, then it’s called a project file. 

A clip is the visual object on the timeline which represents an audio file on your drive. You can position them anywhere you want, and because you’re not operating on a file directly, no data will be lost if you fiddle around with it 

There are different versions of Pro Tools – Artist, Studio and Ultimate 

Artist allows 16 separate audio input/outputs, Studio allows 64 and Ultimate allows 256 

Can work on stereo mixes in Artist, but Studio/Ultimate is required if you want to do Surround mixing 

Option = alt 

Return = enter 

Control = start 

Command = Ctrl 

Pro Tools systems can operate in one of two ways: 

Native – the computer itself does all the processing 

DSP (Digital Signal Processor) - specific hardware is added on to offload tasks 

The more CPU and RAM you have, the better

You should use a separate hard drive, which has a good size and speed

 

You will also need an audio interface – which can connect through computer connections (USB) or Analog Audio Connections:

Monitor speakers – should give you an honest reproduction of your recordings and mixes, without the enhancements built into consumer products.
It will let you hear what your work will sound like on a wide range of playback systems 

They don’t have to be expensive – if it sounds good on cheap speakers, it’ll sound good anywhere 

Frequency response – flattest shape between 20Hz and 20kHz 

Ports – rear-ported speakers need about 1 metre behind them, so if you have a small room then choose front-ported speakers 

 Most professional mixing headphones use an open-back design, which allows sound to pass out of them 

Closed back is good if you don’t want to disturb those around you, or if you’re recording something 

Avid uses PACE anti-piracy software to manage Pro Tools licences 

When you install Pro Tools, another application called Avid Link is also installed